INORGANIC AND ORGANIC LEAD COMPOUNDS

INORGANIC AND ORGANIC LEAD COMPOUNDS Metallic lead and several inorganic and organic lead compounds have been considered ... Boiling-point (°C) 3 Dens...

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INORGANIC AND ORGANIC LEAD COMPOUNDS Metallic lead and several inorganic and organic lead compounds have been considered by previous working groups convened by IARC (IARC, 1972, 1973, 1976, 1980, 1987). New data have since become available, and these are included in the present monograph and have been taken into consideration in the evaluation. The agents considered in this monograph are some inorganic and organic lead compounds.

1.

Exposure Data

1.1

Chemical and physical data

1.1.1

Nomenclature, synonyms, trade names, molecular formulae, chemical and physical properties

Synonyms, trade names and molecular formulae for lead and some inorganic and organic lead compounds are presented in Table 1. The lead compounds shown are those for which data on carcinogenicity or mutagenicity are available or which are commercially most important. The list is not exhaustive. Selected chemical and physical properties of the lead compounds listed in Table 1 are presented in Table 2. Lead (atomic number, 82; relative atomic mass, 207.2) has a valence +2 or +4. The alchemists believed lead to be the oldest metal and associated it with the planet Saturn. Lead is a bluish-white metal of bright lustre, is very soft, highly malleable, ductile and a poor conductor of electricity. It is very resistant to corrosion; lead pipes bearing the insignia of Roman emperors, used as drains from the baths, are still in service (Lide, 2003). Natural lead is a mixture of four stable isotopes: 204Pb (1.4%), 206Pb (25.2%), 207Pb (21.7%) and 208Pb (51.7%) (O’Neil, 2003). Lead isotopes are the end-products of each of the three series of naturally occurring radioactive elements: 206Pb for the uranium series, 207Pb for the actinium series and 208Pb for the thorium series. Forty-three other isotopes of lead, all of which are radioactive, are recognized (Lide, 2003).

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CAS registry numbera

Molecular formula

Molecular weightb

Calcium plumbate

Pigment Brown 10

12013-69-3

Ca2PbO4

[351.4]

c

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Synonyms and trade names (Chemical Abstracts Service name in italics)

207.2c

Pb

Lead acetate

Acetic acid, lead(2+) salt; acetic acid lead salt (2:1); dibasic lead acetate; lead bis(acetate); lead diacetate; lead dibasic acetate; lead(2+) acetate; lead(II) acetate; neutral lead acetate; normal lead acetate; plumbous acetate; salt of Saturn; sugar of lead

301-04-2

Pb(C2H3O2)2

325.3

Lead acetate trihydrate

Acetic acid, lead(2+) salt, trihydrate; lead diacetate trihydrate; lead(II) acetate trihydrate; plumbous acetate trihydrate; sugar of lead

6080-56-4

Pb(C2H3O2)2·3H2O

379.3

Lead arsenate

Arsenic acid (H3AsO4), lead(2+) salt (2:3); lead(2+) orthoarsenate (Pb3(AsO4)2); Nu Rexform; trilead diarsenate

3687-31-8

Pb3(AsO4)2

899.4

Lead azide

Lead azide (Pb(N3)2); lead azide (PbN6); lead diazide; lead(2+) azide; RD 1333

13424-46-9 [85941-57-7]

Pb(N3)2

291.2

Lead bromide

Lead bromide (PbBr2); lead dibromide

10031-22-8

PbBr2

367.0

Lead carbonate

Carbonic acid, lead(2+) salt (1:1); lead carbonate (PbCO3); basic lead carbonate; dibasic lead carbonate; lead(2+) carbonate; plumbous carbonate; cerussite; white lead

598-63-0

PbCO3

267.2

Lead chloride

Lead chloride (PbCl2); lead dichloride; lead(2+) chloride; lead(II) chloride; plumbous chloride; natural cotunite

7758-95-4

PbCl2

278.1

Lead chromate

Chromic acid (H2CrO4), lead(2+) salt (1:1); lead chromate(VI); lead chromate (PbCrO4); lead chromium oxide (PbCrO4); plumbous chromate; Royal Yellow 6000; chrome yellow

7758-97-6 [8049-64-7]

PbCrO4

323.2

Lead fluoride

Lead fluoride (PbF2); lead difluoride; lead difluoride (PbF2); lead(2+) fluoride; plumbous fluoride

7783-46-2 [106496-44-0]

PbF2

245.2

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C.I. 77575; C.I. Pigment Metal 4; Lead element; Lead Flake; Lead S 2; Pb-S 100; SSO 1

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Lead, lead powder

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Table 1. Synonyms and trade names, registry numbers, molecular formulae, and molecular weights for lead and lead compounds

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Table 1 (contd)

Lead fluoroborate

Borate(1-), tetrafluoro-, lead(2+) salt (2:1); borate(1-), tetrafluoro-, lead(2+); lead fluoborate; lead tetrafluoroborate; lead boron fluoride; lead fluoroborate (Pb(BF4)2); lead(II) tetrafluoroborate

13814-96-5 [35254-34-3]

Pb(BF4)2

380.8

Lead hydrogen arsenate

Arsenic acid (H3AsO4), lead(2+) salt (1:1); lead arsenate (PbHAsO4); acid lead arsenate; arsenic acid lead salt; lead acid arsenate; lead arsenate; lead hydrogen arsenate (PbHAsO4); lead(2+) monohydrogen arsenate

7784-40-9 [14034-76-5; 37196-28-4]

PbHAsO4

347.1

Lead iodide

Lead iodide (PbI2); C.I. 77613; lead diiodide; lead(II) iodide; plumbous iodide

10101-63-0 [82669-93-0]

PbI2

461.0

Lead naphthenate

Naphthenic acids, lead salts; lead naphthenates; naphthenic acid, lead salt; Naphthex Pb; Trokyd Lead

61790-14-5

Unspecified

Lead nitrate

Nitric acid, lead(2+) salt; lead dinitrate; lead nitrate (Pb(NO3)2); lead(2+) bis(nitrate); lead(2+) nitrate; lead(II) nitrate; plumbous nitrate

10099-74-8 [18256-98-9]

Pb(NO3)2

331.2

Lead dioxide

Lead oxide (PbO2); C.I. 77580; lead brown; lead oxide brown; lead peroxide; lead superoxide; lead(IV) oxide; plumbic oxide; Thiolead A

1309-60-0 [60525-54-4]

PbO2

239.2

Lead monoxide

Lead oxide (PbO); C.I. 77577; C.I. Pigment Yellow 46; lead monooxide; lead oxide yellow; lead protoxide; lead(2+) oxide; lead(II) oxide; litharge; Litharge S; Litharge Yellow L-28; plumbous oxide; yellow lead ochre

1317-36-8 [1309-59-7; 12359-23-8]

PbO

223.2

Lead trioxide

Lead trioxide (Pb2O3); C.I. 77579; lead sesquioxide; lead sesquioxide (Pb2O3); plumbous plumbate

1314-27-8

Pb2O3

462.4

Lead phosphate

Phosphoric acid, lead(2+) salt (2:3); lead phosphate (Pb3P2O8); C.I. 77622; C.I. Pigment White 30; lead diphosphate; lead orthophosphate; lead phosphate (3:2); lead(2+) phosphate (Pb3(PO4)2); lead(II) phosphate (3:2); Perlex Paste 500; Perlex Paste 600A; Trilead phosphate; lead phosphate dibasic

7446-27-7

Pb3(PO4)2

811.5

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Molecular weightb

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Molecular formula

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CAS registry numbera

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Synonyms and trade names (Chemical Abstracts Service name in italics)

INORGANIC AND ORGANIC LEAD COMPOUNDS

Chemical name

Molecular weightb

Lead phosphite, dibasic

Dibasic lead phosphite; lead dibasic phosphite; dibasic lead metaphosphate; C.I. 77620; lead oxide phosphonate, hemihydrate

1344-40-7

2PbO·PbHPO3·1/2H2O

[743]

Lead molybdate

Lead molybdate(VI); lead molybdate oxide (PbMoO4)

10190-55-3

PbMoO4

367.1

Lead stearate

Octadecanoic acid, lead(2+) salt; 5002G; lead distearate; lead(2+) octadecanoate; lead(2+) stearate; lead(II) octadecanoate; lead(II) stearate; Listab 28ND; Pbst; SL 1000 (stabilizer); SLG; Stabinex NC18; stearic acid, lead(2+) salt

1072-35-1 [11097-78-2; 37223-82-8]

Pb(C18H35O2)2

774.1

Lead stearate, dibasic

Dibasic lead stearate; Listab 51; lead, bis(octadecanoato)dioxodi-; stearic acid, lead salt, dibasic

56189-09-4

2PbO·Pb(C17H35COO)2

1220

Lead styphnate

1,3-Benzenediol, 2,4,6-trinitro-, lead(2+) salt (1:1); 2,4-dioxa-3plumbabicyclo[3.3.1]nona-1(9),5,7-triene, 3,3-didehydro-6,8,9-trinitro-; lead, [styphnato(2-)]-; lead tricinate; lead trinitroresorcinate; Tricinat; 2,4,6-trinitroresorcinol, lead(2+) salt (1:1)

15245-44-0 [4219-19-6; 6594-85-0; 59286-40-7; 63918-97-8]

Pb(C6H3N3O8)

[452.3]

Lead subacetate

Lead, bis(acetato-êO)tetrahydroxytri-; lead acetate (Pb3(AcO)2(OH)4); lead, bis(acetato)-tetrahydroxytri-; lead, bis(acetato-O)tetra-hydroxytri-; bis(acetato)dihydroxytrilead; lead acetate hydroxide (Pb3(OAc)2(OH)4); lead acetate, basic; monobasic lead acetate

1335-32-6

Pb(CH3COO)2·2Pb(OH)2

807.7

Lead sulfate

Sulfuric acid, lead(2+) salt (1:1); Anglislite; C.I. 77630; C.I. Pigment White 3; Fast White; Freemans White Lead; HB 2000; Lead Bottoms; lead monosulfate; lead(II) sulfate (1:1); lead(2+) sulfate; lead(II) sulfate; Milk White; Mulhouse White; TS 100; TS 100 (sulfate); TS-E; sublimed white lead

7446-14-2 [37251-28-8]

PbSO4

303.3

Lead sulfide

Lead sulfide (PbS); C.I. 77640; lead monosulfide; lead sulfide (1:1); lead(2+) sulfide; lead(II) sulfide; natural lead sulfide; P 128; P 37; plumbous sulfide

1314-87-0 [51682-73-6]

PbS

239.3

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Molecular formula

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Table 1 (contd)

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Table 1 (contd) Molecular formula

Molecular weightb

Lead tetraoxide

Lead oxide (Pb3O4); Azarcon; C.I. 77578; C.I. Pigment Red 105; Entan; Gold Satinobre; Heuconin 5; lead orthoplumbate; lead oxide (3:4); lead oxide red; lead tetroxide; Mennige; Mineral Orange; Mineral red; Minium; Minium Non-Setting RL 95; Minium red; Orange Lead; Paris Red; red lead; red lead oxide; Sandix; Saturn Red; trilead tetraoxide; trilead tetroxide; plumboplumbic oxide

1314-41-6 [12684-34-3]

Pb3O4

685.6

Lead thiocyanate

Thiocyanic acid, lead(2+) salt; lead bis(thiocyanate); lead dithiocyanate; lead(2+) thiocyanate; lead(II) thiocyanate

592-87-0 [10382-36-2]

Pb(SCN)2

323.4

Tetraethyl lead

Plumbane, tetraethyl-; lead, tetraethyl-; TEL; tetraethyllead; tetraethylplumbane

78-00-2

Pb(C2H5)4

323.5

Tetramethyl lead

Plumbane, tetramethyl-; lead, tetramethyl-; tetramethyllead; tetramethylplumbane; TML

75-74-1

Pb(CH3)4

267.3

From IARC (1980); Lide (2003); National Library of Medicine (2003); O’Neil (2003); STN International (2003) a Deleted Chemical Abstracts Service numbers shown in square brackets b Values in square brackets were calculated from the molecular formula. c Atomic formula; atomic weight

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CAS registry numbera

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INORGANIC AND ORGANIC LEAD COMPOUNDS

Chemical name

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Density (g/cm3)

Solubility (per 100 g H2O)

Lead, lead powder Lead acetate

Soft silvery-gray metal; cubic White crystal

327.5 280

1749 Dec.

11.3 3.25

Lead acetate trihydrate

Colourless crystal

75 (dec)



2.55

Lead arsenate Lead azide

White crystal Colourless orthorhombic needle

1042 (dec) ~350 (expl)

– –

5.8 4.7

Lead bromide

White orthorhombic crystal

371

892

6.69

Lead carbonate

Colourless orthorhombic crystal

~315 (dec)



6.6

Lead chloride

White orthorhombic needle or powder Yellow-orange monoclinic crystals White orthorhombic crystal Stable only in aqueous solution White monoclinic crystal

501

951

5.98

844



6.12

830 – 280 (dec)

1293 –

8.44 – 5.94

410

872 (dec)

6.16

Lead molybdate

Yellow hexagonal crystal or powder Yellow tertiary crystal

Insol. in water; sol. in conc. acid 44.3 g at 20 °C; sl. sol. in ethanol 45.6 g at 15 °C; sl. sol. in ethanol Insol. in water; sol. in nitric acid 23 mg at 18 °C; v. sol. in acetic acid 975 mg at 25 °C; insol. in ethanol Insol. in water; sol. in acid and alkaline solutions 1.08 g at 25 °C; sol. in alkaline solutions; insol. in ethanol 17 µg at 20 °C; sol. in dilute acids 67 mg at 25 °C Sol. in water Insol. in water; sol. in nitric acid and alkaline solutions 76 mg at 25 °C; insol. in ethanol

∼1060



6.7

Insol. in water; sol. in nitric acid and sodium hydroxide

Lead naphthenate Lead nitrate

No data available Colourless cubic crystal

470



4.53

59.7 g at 25 °C; sl. sol. in ethanol

Lead chromate Lead fluoride Lead fluoroborate Lead hydrogen arsenate Lead iodide

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Boiling-point (°C)

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Physical form

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Table 2. Physical and chemical properties of lead and lead compounds

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Table 2 (contd) Density (g/cm3)

Solubility (per 100 g H2O)

Lead monoxide (PbO); litharge Massicot

Red tetrahedral crystal

Transforms to massicot at 489 °C 897



9.35



9.64

Lead trioxide (Pb2O3)

530 (dec)



10.05

Lead phosphate

Black monoclinic crystal or red amorphous powder White hexagonal crystal

1014



7.01

Insol. in water and ethanol; sol. in dilute nitric acid Insol. in water and ethanol; sol. in dilute nitric acid Insol. in water; sol. in alkaline solutions Insol. in water and ethanol; sol. in alkali and nitric acid

Lead phosphite, dibasic Lead stearate

Pale yellow powder White powder

~100



6.1 1.4

Lead styphnate Lead subacetate Lead sulfate

No data available White powder Orthorhombic crystal

Dec. 1087

– –

– 6.29

Lead sulfide

1113



7.60

Lead tetraoxide

Black powder or silvery cubic crystal Red tetrahedral crystals

830



8.92

Lead thiocyanate Tetraethyl lead

White to yellowish powder Liquid

– –136

– 200 (dec)

3.82 1.653 at 20 °C

Tetramethyl lead

Liquid

–30.2

110

1.995 at 20 °C

Yellow orthorhombic crystal

Insol. in water; sol. in hot ethanol 6.3 g at 0 °C; 25 g at 100 °C 4.4 mg at 25 °C; sl. sol. in alkaline solutions; insol. in acids Insol. in water; sol. in acids Insol. in water and ethanol; sol. in hot hydrochloric acid 50 mg at 20 °C Insol. in water; sol. in benzene; sl. sol. in ethanol and diethyl ether Insol. in water; sol. in benzene, ethanol and diethyl ether

45

From IARC (1980); Lide (2003); Physical and Theoretical Chemistry Laboratory (2004) Abbreviations: conc., concentrated; insol., insoluble; sl. sol., slightly soluble; sol., soluble; v. sol., very soluble; dec, decomposes; expl., explodes

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Physical form

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Chemical name

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1.1.2

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Technical products and impurities

Lead is produced in purity greater than 99.97% in many countries. Lead oxides and mixtures of lead and lead oxides are also widely available. Tables 3 and 4 show the specifications for metallic lead and some lead compounds, respectively, from selected countries.

Table 3. Specifications for metallic lead from selected countries Country

% Pb (min.)

Contaminants with limits (% max.a)

Reference

Argentina

99.97

Fe, 0.002; Sb, 0.004; Zn, 0.001; Cu, 0.002; Ag, 0.0095; Bi, 0.035; Cd, 0.001; Ni, 0.001

Industrias Deriplom SA (2003)

Australia

99.97–99.99

Ag, 0.001; As, 0.001; Bi, 0.005–0.029; Cu, 0.001; Sb, 0.001; Zn, 0.001; Cd, 0.001

Pasminco Metals (1998)

Belgium

99.9–99.95

(ppm) Bi, 90–250; Ag, 10–15; Cu, 5–10; As, 5; Sb, 3; Sn, 3; As+Sb+Sn, 8; Zn, 3–5; Fe, 3; Cd, 3–10; Ni, 2–3

Umicore Precious Metals (2002)

Bulgaria

99.97–99.99

Ag, 0.001–0.005; Cu, 0.0005–0.003; Zn, 0.0002–0.0015; Fe, 0.001; Cd, 0.0002– 0.001; Ni, 0.0005–0.001; As, 0.0005–0.002; Sb, 0.0005–0.005; Sn, 0.0005–0.001; Bi, 0.005–0.03

KCM SA (2003)

Canada

99.97–99.99

NR

Noranda (2003); Teck Cominco (2003)

Kazakhstan

99.95–99.9996

NR

Southpolymetal (2003)

Mexico

99.97–99.99

Ag, 0.0015; Cu, 0.0005; Zn, 0.0005; Fe, 0.0010; Bi, 0.0250; Sb, 0.0005; As, 0.0005; Sn, 0.0005; Ni, 0.0002; Te, 0.0001

Penoles (2003)

Republic of Korea

99.995

Ag, 0.0003; Cu, 0.0003; As, 0.0003; Sb, 0.0003; Zn, 0.0003; Fe, 0.0003; Bi, 0.0015; Sn, 0.0003

Korea Zinc Co. (2003)

USA

99.995– 99.9999

(ppm) Sb, 1; As, 1–5; Bi, 0.2–4; Cu, 1–4; Ag, < 0.1–2; Tl, 1–2; Sn, 0.3–1; Fe, < 0.1– 0.3; Ca, 0.1–0.4; Mg, 0.1–0.3

ESPI Corp. (2002)

NR, not reported a Unless otherwise specified

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Table 4. Specifications for some lead compounds from selected countries Gradea

Reference

Argentina

Lead oxide

Fe, 0.003; Sb, 0.001–0.004; Zn, 0.0005– 0.001; Cu, 0.0005–0.002; Ag, 0.001–0.0095; Bi, 0.003–0.035; Cd, 0.0008–0.001; Ni, 0.0008–0.001

5 grades of red lead (Pb3O4 + PbO2 + PbO); 3 grades of yellow litharge (PbO, 99.65– 99.96%; free Pb, 0.03–0.30%; Pb3O4, 0.0048–0.05%); 1 grade of green powder (PbO + Pb, 80%+20% or 62%+38%)

Industrias Deriplom SA (2003)

Australia

Lead oxide

Bi, 0.05–0.06; Ag, 0.001; Cu, 0.001; Sn, 0.0005–0.001; Sb, 0.0001–0.0002; As, 0.0001; Se, 0.0001; S, 0.0007; Cd, 0.0005; Ni, 0.0002–0.0003; Zn, 0.0005; Fe, 0.0002– 0.0005; Mn, 0.0003–0.0005; Te, 0.00003– 0.0001; Co, 0.0001–0.0002; Cr, 0.0002; Ba, 0.0005; V, 0.0004; Mo, 0.0003–0.0005

VRLA-refinedTM and MF-refinedTM

Pasminco Metals (2000)

USA

Lead acetate Lead bromide Lead chloride Lead fluoride Lead iodide Lead molybdate Lead monoxide Lead tetraoxide Lead sulfide

NR

5N 3N and 5N 3N and 5N 3N 3N and 5N 3N 3N and 5N 3N 3N and 5N

ESPI Corp. (2002)

VRLA, valve-regulated lead acid; MF, maintenance-free; NR, not reported a 3N, 99.9%; 5N, 99.999%

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Production

Commercial lead metal is described as being either primary or secondary. Primary lead is produced directly from mined lead ore. Secondary lead is produced from scrap lead products which have been recycled. 1.2.1

The ores and their preparation

The most important lead ore is galena (lead sulfide). Other important ores such as cerussite (lead carbonate) and anglesite (lead sulfate) may be regarded as weathered products of galena and are usually found nearer to the surface of the earth’s crust. Lead and zinc ores often occur together and, in most extraction methods, have to be separated. The most common separation technique is selective froth flotation. The ore is first processed to a fine suspension in water by grinding in ball or rod mills — preferably to a particle size of < 0.25 mm. Air is then bubbled through this pulp contained in a cell or tank and, following the addition of various chemicals and proper agitation, the required mineral particles become attached to the air bubbles and are carried to the surface to form a stable mineral-containing froth which is skimmed off. The unwanted or gangue particles are unaffected and remain in the pulp. For example, with lead–zinc sulfide ores, zinc sulfate, sodium cyanide or sodium sulfite can be used to depress the zinc sulfide, while the lead sulfide is floated off to form a concentrate. The zinc sulfide is then activated by copper sulfate and floated off as a second concentrate (Lead Development Association International, 2003a). Around 3 million tonnes of lead are mined in the world each year. Lead is found all over the world but the countries with the largest mines are Australia, China and the United States of America, which together account for more than 50% of primary production. The most common lead ore is galena (lead sulfide). Other elements frequently associated with lead include zinc and silver. In fact, lead ores constitute the main sources of silver, contributing substantially towards the world’s total silver output (Lead Development Association International, 2003b). Table 5 shows mine production of lead concentrate by country in the year 2000. Table 6 shows the trends in lead mine production by geographic region from 1960 to 2003. 1.2.2

Smelting (a)

Two-stage processes

The first stage in smelting consists of removing most of the sulfur from the lead concentrate. This is achieved by a continuous roasting process (sintering) in which the lead sulfide is largely converted to lead oxide and broken down to a size convenient for use in a blast furnace — the next stage in the process. The sinter plant gases containing sulfur are converted to sulfuric acid (Lead Development Association International, 2003a).

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Table 5. Mine production of lead concentrate in 2000a Country

Algeria Argentina Australia Bolivia Bosnia and Herzegovina Brazil Bulgaria Canada Chile China Colombia Democratic People’s Republic of Korea Ecuador Georgia Greece Honduras India Iran Ireland Italy Japan Kazakhstan

Production (tonnes) 818 14 115 739 000 9 523 200b 8 832 10 500 152 765 785c 660 000b 226 60 000b,c 200b 200b 18 235b 4 805 28 900 15 000b 57 825 2 000 8 835 40 000

Country

Mexico Morocco Myanmar Namibia Peru Poland Republic of Korea Romania Russian Federation Serbia and Montenegro South Africa Spain Sweden Tajikistan Thailand The former Yugoslav Republic of Macedonia Tunisia Turkey United Kingdom USA Viet Nam World totald

Production (tonnes) 137 975 81 208c 1 200b 11 114c 270 576 51 200c 2 724 18 750c 13 300 9 000 75 262 40 300 106 584c 800b 15 600 25 000b 6 602 17 270 1 000b 465 000 1 000b 3 180 000c

From Smith (2002) In addition to the countries listed, lead is also produced in Nigeria, but information is inadequate to estimate output. a Data available at 1 July 2003 b Estimated c Revised d Data from the USA and estimated data are rounded to no more than three significant digits, so that values may not add to total shown.

The graded sinter (lead oxide) is mixed with coke and flux, such as limestone, and fed into the top of the blast furnace, where it is smelted using an air blast (sometimes preheated) introduced near the bottom. The chemical processes that take place in the furnace at about 1200 °C result in the production of lead bullion (lead containing only metallic impurities) which is tapped off from the bottom of the furnace and either cast into ingots or collected molten in ladles for transfer to the refining process. In the Imperial Smelting Furnace process, a very similar procedure is used for the simultaneous production of zinc and lead. These traditional two-stage processes largely favour the release of hazardous dusts and fumes. They necessitate the use of extensive exhaust ventilation and result in large volumes

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Table 6. Trends in lead mine production worldwide Production (thousand tonnes) by geographical regiona

Year

1960 1965 1970 1975 1980 1985 1990 1995 2000 2003

Ab

B

C

Db

E

Fb

Total

370 366 476 435 482 412 727 382 360 218

207 250 210 165 278 261 175 186 178 123

822 984 1341 1340 1298 1197 1184 1047 1053 1043

84 99 120 140 112 155 545 715 805 770

306 361 441 395 382 474 556 424 650 666

583 724 855 1085 1030 1076 NRS NRS NRS NRS

2372 2784 3443 3560 3582 3575 3187 2753 3046 2821

From International Lead and Zinc Study Group (1990, 2004) NRS, not reported separately a Data from following countries: A, Austria, Denmark, Finland, France, Germany (the Federal Republic of Germany before reunification), Greece, Ireland, Italy, Norway, Portugal, Spain, Sweden, United Kingdom and former Yugoslavia B, Algeria, Congo, Morocco, Namibia, South Africa, Tunisia and Zambia C, Argentina, Bolivia, Brazil, Canada, Chile, Colombia, Guatemala, Honduras, Mexico, Nicaragua, Peru and USA D, Myanmar, India, Iran, Japan, Philippines, Republic of Korea, Thailand and Turkey E, Australia F, Bulgaria, China, former Czechoslovakia, Hungary, People’s Democratic Republic of Korea, Poland, Romania and the former Soviet Union; values for the latter four countries are estimates. b From 1990 onwards, data from region F are included in region A (for Belarus, Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, the Russian Federation, Slovakia and Ukraine) or region D (for all former Soviet Republics, China and People’s Democratic Republic of Korea); lead mine production for 1991 in the former Soviet Union is split as follows: Europe, 19%; Asia, 81%.

of lead-laden exhaust gases which are usually cleaned before they are discharged into the atmosphere. The collected dusts are returned to the smelting process (Lead Development Association International, 2003a). (b)

Direct smelting processes

The environmental problems and inefficient use of energy associated with the sinter/ blast furnace and Imperial Smelting Furnace processes have led to a considerable amount of research into more economical and less polluting methods for the production of lead. Most of this research has been aimed at devising processes in which lead is converted directly from the sulfide to the metal without producing lead oxide. As a result, a number

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of direct smelting processes now exist, although at varying stages of development (Lead Development Association International, 2003a). Direct smelting processes offer several significant advantages over conventional methods. The first and most obvious advantage is that sintering is no longer necessary. As a result, the creation of dust, a major occupational and environmental problem, is avoided. Moreover, the heat evolved during sintering (for the oxidation of the ore) is no longer wasted but is used in the smelting operation, thus providing a considerable saving of fuel. The volumes of gas that require filtering are largely reduced and, at the same time, the sulfur dioxide concentration of the off-gases is greater and these are therefore more suitable for the manufacture of sulfuric acid. The major difficulty in all direct smelting processes lies in obtaining both a lead bullion with an acceptably low sulfur content and a slag with a sufficiently low lead content for it to be safely and economically discarded. In several cases, further treatment of the crude bullion or the slag or both is required in a separate operation. There are several direct smelting processes which come close to meeting the desired criteria — the Russian Kivcet, the QSL (Queneau–Schuhmann– Lurgi), the Isasmelt and the Outokumpu processes are examples. The use of these newer processes will probably increase. At present, the relative importance of the different smelting methods in terms of amounts of metal produced is as follows: conventional blast furnace, 80%; Imperial Smelting Furnace process, 10%; and direct processes, 10% (Lead Development Association International, 2003a). 1.2.3

Hydrometallurgical processes

With the prospect of even tighter environmental controls, the possibilities of utilizing hydrometallurgical techniques for the treatment of primary and secondary sources of lead are being investigated. Several processes have been described in the literature, but most are still in the developmental stage and probably not yet economically viable in comparison with the pyrometallurgical (smelting) processes. The goal of the hydrometallurgical processes in most cases is to fix the sulfur as a harmless sulfate and to put the lead into a solution suitable for electrolytic recovery. Most of these processes recirculate leach solutions and produce lead of high purity. For example, the Ledchlor process can be used on primary materials; other methods such as Rameshni SO2 Reduction (RSR) and the processes developed by Engitec (CX-EW) and Ginatta (Maja et al., 1989) are more concerned with recovery of lead from secondary sources, in particular from battery scrap (Lead Development Association International, 2003a). 1.2.4

Primary lead refining

Apart from gold and silver, lead bullion contains many other metallic impurities including antimony, arsenic, copper, tin and zinc. Copper is the first of the impurities to be removed. The lead bullion is melted at about 300–600 °C and held just above its

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melting-point when solid copper rises to the surface and is skimmed off. Sulfur is stirred into the melt to facilitate the operation by producing a dry powdery dross which is more readily removed. Once copper has been removed, there are a number of processes available for the extraction of the other impurities from the bullion. These include pyrometallurgical techniques, in which elements are removed one or more at a time in several stages, and electrolytic processes that remove most of the impurities in one operation. Although electrolytic methods are used in large-scale production, pyrometallurgical techniques account for the larger portion of the world’s refined lead production (Lead Development Association International, 2003c). Table 7 shows the trends in production of refined lead by geographic region from 1960 to 2003.

Table 7. Trends in refined lead production worldwide Year

1960 1965 1970 1975 1980 1985 1990 1995 2000 2003

Production (thousand tonnes) by geographical regiona Ab

B

C

Db

E

Fb

Total

950 1046 1412 1354 1514 1613 2323 1796 1882 1606

70 124 147 124 156 159 150 141 125 144

1114 1296 1619 1661 1776 1708 1900 2102 2216 2043

164 202 301 296 397 539 924 1474 2163 2499

211 223 217 198 241 220 229 243 263 311

718 823 992 1195 1331 1416 NRS NRS NRS NRS

3227 3714 4688 4828 5415 5655 5525 5756 6650 6603

From International Lead and Zinc Study Group (1990, 2004) NRS, not reported separately a Data from the following countries: A, Austria, Belgium, Denmark, Finland, France, Germany (the Federal Republic of Germany before reunification), Greece, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom and former Yugoslavia B, Algeria, Morocco, Namibia, South Africa, Tunisia and Zambia C, Argentina, Brazil, Canada, Mexico, Peru, USA and Venezuela D, Myanmar, India, Indonesia, Japan, Malaysia, Philippines, Republic of Korea, China (Province of Taiwan), Thailand, and Turkey E, Australia and New Zealand F, Bulgaria, China, former Czechoslovakia, Germany (former Democratic Republic of), Hungary, People’s Democratic Republic of Korea, Poland, Romania and former Soviet Union; values for Bulgaria, former German Democratic Republic, Romania, former Soviet Union, China and People’s Democratic Republic of Korea are estimates. b From 1990 onwards, data from region F are included in region A (Belarus, Bulgaria, Czech Republic, Estonia, Germany (former German Democratic Republic), Hungary, Latvia, Lithuania, Poland, Romania, Russian Federation and Ukraine) or in region D (China, all other former Soviet Republics and People’s Democratic Republic of Korea); refined lead production in the former Soviet Union for 1991 is split as follows: Europe, 24%; Asia, 76%.

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53

Pyrometallurgical processes

(i) Removal of antimony, arsenic and tin After the removal of copper, the next step is to remove antimony, arsenic and tin. There are two methods available — the softening process (so-called since these elements are standard hardeners for lead) and the Harris process. In the softening process, the lead bullion is melted and agitated with an air blast, causing preferential oxidation of the impurities which are then skimmed off as a molten slag. In the Harris process, the molten bullion is stirred with a flux of molten sodium hydroxide and sodium nitrate or another suitable oxidizing agent. The oxidized impurities are suspended in the alkali flux in the form of sodium antimonate, arsenate and stannate, and any zinc is removed in the form of zinc oxide (Lead Development Association International, 2003c). (ii) Removal of silver and gold After the removal of antimony, arsenic and tin, the softened lead may still contain silver and gold, and sometimes bismuth. The removal of the precious metals by the Parkes process is based on the fact that they are more soluble in zinc than in lead. In this process, the lead is melted and mixed with zinc at 480 °C. The temperature of the melt is gradually lowered to below 419.5 °C, at which point the zinc (now containing nearly all the silver and gold) begins to solidify as a crust on the surface of the lead and can be skimmed off. An alternative procedure, the Port Pirie process, used at the Port Pirie refinery in Australia, is based on similar metallurgical principles (Lead Development Association International, 2003c). (iii) Removal of zinc The removal of the precious metals leaves zinc as the main contaminant of the lead. It is removed either by oxidation with gaseous chlorine or by vacuum distillation. The latter process involves melting the lead in a large kettle covered with a water-cooled lid under vacuum. The zinc distils from the lead under the combined influence of temperature and reduced pressure and condenses on the underside of the cold lid (Lead Development Association International, 2003c). (iv) Removal of bismuth After removal of zinc, the only remaining impurity is bismuth, although it is not always present in lead ore. It is easily removed by electrolysis and this accounts for the favouring of electrolytic methods in Canada (see below), where bismuth is a frequent impurity. When pyrometallurgical methods of refining are used, bismuth is removed by adding a calcium–magnesium alloy to the molten lead, causing a quaternary alloy of lead–calcium–magnesium–bismuth to rise to the top of the melt where it can be skimmed off (Lead Development Association International, 2003c).

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(b)

Electrolytic processes

In the Betts process, massive cast anodes of lead bullion are used in a cell containing an electrolyte of acid lead fluorosilicate and thin cathode ‘starter sheets’ of high-purity lead. The lead deposited on the cathodes still contains tin and sometimes a small amount of antimony, and these impurities must be removed by melting and selective oxidation. For many years, the Betts process was the only process to remove bismuth efficiently. A more recent electrolytic process, first used in the 1950s in Italy, employs a sulfamate electrolyte. It is claimed to be an equally efficient refining method, with the advantage that the electrolyte is easier to prepare (Lead Development Association International, 2003c). By combining the processes described above to build up a complete refining scheme, it is possible to produce lead of very high purity. Most major refiners will supply bulk quantities of lead of 99.99% purity and, for very specific purposes, it is possible to reach 99.9999% purity by additional processing (Lead Development Association International, 2003c). 1.2.5

Secondary lead production

Much of the secondary lead comes from lead batteries, with the remainder originating from other sources such as lead pipe and sheet. Lead scrap from pipes and sheet is ‘clean’ and can be melted and refined without the need for a smelting stage. With batteries, the lead can only be obtained by breaking the case open. This is commonly done using a battery breaking machine which, in addition to crushing the case, separates out the different components of the battery and collects them in hoppers. Thus, the pastes (oxide and sulfate), grids, separators and fragmented cases are all separated from one another. The battery acid is drained and neutralized, and the other components are either recycled or discarded (Lead Development Association International, 2003d). Table 8 shows trends in recovery of secondary lead by geographic region from 1970 to 1988. Three million tonnes of lead are produced from secondary sources each year, by recycling scrap lead products. At least three-quarters of all lead is used in products which are suitable for recycling and hence lead has the highest recycling rate of all the common non-ferrous metals (Lead Development Association International, 2003a). Almost 50% of the 1.6 million tonnes of lead produced in Europe each year has been recycled. In the United Kingdom, the figure is nearer 60% (Lead Development Association International, 2003d). (a)

Secondary lead smelting

The workhorse of the secondary lead production industry used to be the blast furnace. Conversion from blast to rotary-furnace technology in Europe began in the 1960s and was largely complete by the 1990s, driven by the high price of metallurgical coke and the relative difficulty of preventing the escape of dust and fume. The blast furnace was used to provide a low-grade antimonial lead, which was softened. The high-antimony slags were accumulated for a subsequent blast furnace campaign to produce a high-antimony bullion

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Table 8. Trends in recovery of secondary lead (refined lead and lead alloys produced from secondary materials) Year

1970 1975 1980 1985 1988

Recovery (thousand tonnes) by geographical regiona A

B

C

D

E

Total

619 617 742 766 800

21 29 44 44 48

532 610 798 747 921

78 115 192 258 310

37 39 39 20 23

1287 1410 1815 1835 2102

From International Lead and Zinc Study Group (1990) a Data from the following countries: A, Austria, Belgium, Denmark, Finland, France, Germany (the Federal Republic of Germany before reunification), Greece, Ireland, Italy, Netherlands, Portugal, Spain, Sweden, Switzerland, United Kingdom and former Yugoslavia B, Algeria, Morocco and South Africa C, Argentina, Brazil, Canada, Mexico, USA and Venezuela D, India, Japan and China (Province of Taiwan) E, Australia and New Zealand

for blending into lead alloys. Although a few secondary smelters today still use furnaces based on blast furnace technology, most companies now use rotary furnaces in which the charge can be tailored to give a lead of approximately the desired composition. Alternatively, a two-stage smelting procedure can be employed, which yields crude soft lead and crude antimonial lead. In the latter process, for example, battery plates are first melted and crude soft lead is tapped off after a few hours while the antimonial slag and lead oxide and sulfate are retained in the furnace. Further plates are charged and more soft lead is withdrawn until sufficient slag has accumulated for the slag reduction stage. Then, coke or anthracite fines and soda ash are added, lead and antimony oxides and lead sulfate are reduced and the cycle ends with the furnace being emptied of antimonial lead and of slag for discarding. As with primary smelting, large volumes of gas are produced, carrying substantial quantities of dust. On leaving the smelter, the gases are cooled from about 900 °C to about 100 °C using air and/or water cooling, and pass into a baghouse where the dust is collected and eventually fed back into the smelter. The gases subsequently are released into the atmosphere. In the course of processing one tonne of lead, as much as 100 tonnes of air have to be cleaned in this way (Lead Development Association International, 2003d). In the semi-continuous Isasmelt furnace process used for secondary lead production, the furnace is fed with a lead carbonate paste containing 1% sulfur. This is obtained as a result of the battery paste having gone through a desulfurizing process after battery breaking. Over the following 36 h, wet lead carbonate paste and coal as a reductant are continuously fed into the furnace. The soft lead that is produced is tapped every 3 h and

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contains 99.9% lead. After 36 h, the paste feed is stopped and the slag is reduced to produce antimonial lead alloy. As with the two-stage process described above, off-gases from the furnace are first cooled and then passed into a baghouse for fume and dust control (Lead Development Association International, 2003d). (b)

Secondary lead refining

The principal impurities that are removed in secondary lead refining are copper, tin, antimony and arsenic. Zinc, iron, nickel, bismuth, silver and other impurities may also be present. These impurities are generally removed using the same basic techniques as described above (Lead Development Association International, 2003d). 1.2.6

Lead production by compound and country

Table 9 summarizes the available information on the number of companies in various countries producing metallic lead and some lead compounds in 2002. 1.3

Use

Over the centuries the unique properties of lead have resulted in its use in many different applications. These properties are mainly its high resistance to corrosion, its softness and low melting-point, its high density and its relatively low conductivity (Lead Development Association International, 2003b). Large quantities of lead, both as the metal and as the dioxide, are used in storage batteries. Lead is also used for cable covering, plumbing and ammunition. The metal is very effective as a sound absorber and as a radiation shield around X-ray equipment and nuclear reactors. It is also used to absorb vibration. Lead, alloyed with tin, is used in making organ pipes. Lead carbonate (PbCO3), lead sulfate (PbSO4), lead chromate (PbCrO4), lead tetraoxide (Pb3O4) and other lead compounds (see Table 1 for synonyms) have been applied extensively in paints, although in recent years this use has been curtailed to reduce health hazards. Lead oxide (usually lead monoxide) is used in the production of fine ‘crystal glass’ and ‘flint glass’ with a high index of refraction for achromatic lenses. Lead nitrate and acetate are soluble salts that serve as intermediates and in specialty applications. Lead salts such as lead arsenate have been used as insecticides, but in recent years this use has been almost eliminated (Lide, 2003). In most countries, lead is predominantly used as the metal and it may be alloyed with other materials depending on the application. Lead alloys are made by the controlled addition of other elements. The term ‘unalloyed lead’ implies that no alloying elements have been added intentionally; this may mean that the lead is of high purity, but the term also covers less pure lead containing incidental impurities (Lead Development Association International, 2003e).

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Table 9. Lead production by compound and country Compound

No. of companies

Countries

Metallic lead

10 6 5 4 3 2 1

Lead acetate

10 8 7 6 5 3 2 1

Lead arsenate

3 1 2 1 1 6 2 1

Japan USA China, Mexico Belgium, Canada Brazil, Germany, Peru, Russian Federation Kazakhstan Argentina, Australia, Bolivia, Bulgaria, China (Province of Taiwan), Egypt, India, Ireland, Italy, Netherlands, Republic of Korea, Spain, Sweden, Turkey China India Mexico USA Brazil, Japan Spain Germany, Italy Australia, China (Province of Taiwan), France, Romania, Russian Federation Japan Peru Brazil Japan Germany, India, Japan, United Kingdom, USA India China, China (Province of Taiwan), Germany, USA Argentina, Australia, Italy, Japan, Mexico, Republic of Korea, Romania, Ukraine and United Kingdom India USA Australia, Belgium, China, China (Province of Taiwan), Germany, Japan, Mexico, Romania, Spain China India USA China (Province of Taiwan), Japan, Spain Germany, Italy Brazil, Republic of Korea, Netherlands, United Kingdom Argentina, Austria, Belgium, Canada, Colombia, France, Mexico, Peru, Romania, Russian Federation, Turkey, Venezuela China India, Japan, USA Argentina, Canada, France, Germany

Lead azide Lead bromide Lead carbonate

Lead chloride

5 4 1

Lead chromate (Pigment Yellow 34)

22 8 6 5 3 2 1

Lead fluoride

4 3 1

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Table 9 (contd) Compound

Lead fluoroborate

Lead iodide Lead naphthenate

Lead nitrate

Lead monoxide

Lead dioxide

Lead phosphate

Lead stearate

No. of companies 7 5 3 2 1 2 1 6 5 3 2 1 12 8 7 6 4 3 2 1 24 7 6 4 3 2 1 6 4 3 2 1 6 2 1 25 17 9 4 3 2 1

Countries

China, India USA Japan Australia, China (Province of Taiwan), France, Germany Argentina, Brazil, Russian Federation, Spain Japan, United Kingdom China, India, USA China Japan, Mexico Argentina, USA France, India, Peru, Spain Australia, Belgium, Brazil, Canada, China (Province of Taiwan), Germany, Italy, Romania, Thailand, Turkey India China USA Japan Brazil, Mexico Spain Belgium, Germany Australia, Italy, Russian Federation, Tajikistan China Japan India China (Province of Taiwan), Germany, Mexico, USA France, Spain Brazil, Italy, Peru, Republic of Korea, Russian Federation Argentina, Australia, Canada, Kazakhstan, Malaysia, Portugal, South Africa, Tajikistan, Turkey, United Kingdom India Japan USA Germany Australia, Italy, South Africa, Spain, United Kingdom China India Japan, Russian Federation China India China (Province of Taiwan) Japan Germany, Spain, Thailand Mexico, Peru, Philippines, Republic of Korea, USA Albania, Argentina, Belgium, Brazil, Indonesia, Italy, Portugal, Romania, South Africa, Turkey

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Table 9 (contd) Compound

No. of companies

Countries

Lead stearate, dibasic

15 8 5 2 1

Lead styphnate

2 1 4 3 2 1

India China China (Province of Taiwan) Japan, Philippines, Spain, Thailand, USA Belgium, Germany, Indonesia, Peru, Republic of Korea, South Africa, Turkey, United Kingdom Brazil Japan India Mexico China Australia, Brazil, China (Province of Taiwan), Romania, Spain, USA India Mexico Germany Spain China, Japan, Romania, USA India France, Japan Austria, China, Germany, USA China India, Japan China (Province of Taiwan) Mexico, Spain Brazil, France, Germany, Italy, Russian Federation, USA Argentina, Kazakhstan, Peru, Poland, Portugal, Republic of Korea, South Africa, Tajikistan, Turkey, United Kingdom USA China Germany, Italy Russian Federation Italy

Lead subacetate

Lead sulfate

Lead sulfide

Lead tetraoxide

Lead thiocyanate Lead trioxide Tetraethyl lead Tetramethyl lead

6 4 3 2 1 4 2 1 22 5 4 3 2 1 2 1 1 2 1

From Chemical Information Services (2003)

59

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Trends in the reported consumption of lead by geographical region between 1960 and 2003 are shown in Table 10. Tables 11 and 12 show the trends in total lead consumption by country and by major use category, respectively, in selected countries between 1985 and 2001. For six of the major lead-consuming countries (France, Germany, Italy, Japan, the United Kingdom, USA), detailed historical data are available from 1960 to 1990 (Tables 13–19). In this period, total consumption of lead reported by these countries rose from 2.06 to 2.94 million tonnes, an overall increase of 43% and an average annual increase of 1.2%. During those three decades, however, there were marked changes in the rates of lead consumption. These included: (1) the rapid expansion of consumption during the 1960s and early 1970s leading to peak levels in 1973 prior to the onset of the first world energy crisis; (2) the steep reduction in 1974–75 and the subsequent revival in 1977–79, with lead consumption recovering to its 1973 level; (3) the decrease in 1980–82 during the second energy crisis; and (4) the sustained growth from 1983 until 1990 in the industrialized world as a whole, supported by rapid advances in some of the newly-industrializing countries, but with much more restricted progress in the fully-industrialized countries where the rates of economic expansion and industrial activity slowed down compared with those previously achieved (International Lead and Zinc Study Group, 1992). 1.3.1

Lead–acid batteries

By far the largest single application of lead worldwide is in lead–acid batteries. The most common type of lead–acid battery consists of a heavy duty plastic box (normally polypropylene) containing grids made from a lead–antimony alloy (commonly containing 0.75–5% antimony) with minor additions of elements such as copper, arsenic, tin and selenium to improve grid properties. For the new generation of sealed, maintenance-free batteries, a range of lead–calcium–tin alloys is used. These contain up to 0.1% calcium and 0–0.5% tin. The tin-containing alloys are used in the positive grids to protect against corrosion. Grids are still manufactured in pairs on special casting machines, but production of grids in strip form by continuous casting or expansion of rolled sheet is becoming increasingly popular as it facilitates automation and minimizes the handling of plates. The spaces in the grids are filled with a paste consisting largely of lead dioxide. When immersed in sulfuric acid, these pasted grids (plates) form an electric cell that generates electricity from the chemical reactions that take place. The reactions require the presence of lead dioxide and lead metal and each cell produces a voltage of 2V. These reactions are reversible and the battery can therefore be recharged. A rechargeable cell is known as a secondary cell and provides a means of storing electricity. Lead is well suited for this application because of its specific conductivity and its resistance to corrosion. The addition of antimony or calcium gives the lead an increased hardness to resist the mechanical stresses within the battery caused, for example, by the natural vibration of road vehicles and by the chemical reactions taking place (Lead Development Association International, 2003e).

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Table 10. Trends in total industrial consumption of refined lead Year

1960 1965 1970 1975 1980 1985 1990 1995 2000 2003

Consumption (thousand tonnes) by geographical regiona Ab

B

C

Db

E

Fb

Total

1152 1306 1517 1403 1652 1614 2439 1948 2022 2030

19 33 46 76 102 98 114 112 130 154

986 1229 1488 1454 1476 1510 1648 2017 2332 2012

204 270 360 413 600 735 1193 1718 1989 2471

65 70 72 86 85 69 59 84 46 45

654 762 1019 1310 1446 1470 NRS NRS NRS NRS

3080 3670 4502 4742 5361 5496 5454 5879 6519 6712

From International Lead and Zinc Study Group (1990, 2004) NRS, not reported separately a Data from the following countries: A, Austria, Belgium, Denmark, Finland, France, Germany (the Federal Republic of Germany before reunification), Greece, Ireland, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom and former Yugoslavia B, Algeria, Egypt, Morocco, South Africa, Tunisia and Zambia C, Argentina, Brazil, Canada, Mexico, Peru, USA and Venezuela D, India, Iran, Japan, Malaysia, Philippines, Republic of Korea, China (Province of Taiwan), Thailand and Turkey E, Australia and New Zealand F, Albania, Bulgaria, China, Cuba, former Czechoslovakia, Germany (the former German Democratic Republic), Hungary, People’s Democratic Republic of Korea; Poland, Romania, former Soviet Union; values for Albania, Cuba, China, Germany (the former German Democratic Republic), Peoples’ Democratic Republic of Korea, Romania and former Soviet Union are estimates. b From 1990 onwards, data from countries in region F are included in region A (Albania, Bulgaria, Czech Republic, Hungary, Poland, the former German Democratic Republic, Poland, Romania, Estonia, Latvia, Lithuania, Belarus, Russian Federation and Ukraine) or in region D (all other former Soviet Republics, China, Cuba and People’s Democratic Republic of Korea). Lead metal consumption for 1991 in the former Soviet Union was split as follows: Europe, 86%, Asia, 14%.

The most common form of lead–acid battery is the so-called SLI battery (starting, lighting and ignition) used in road vehicles such as cars and trucks. Another form, the traction battery, is used to power vehicles such as golf carts and airport support vehicles. Other uses of lead power include larger stationary batteries for stand-by emergency power storage in hospitals and other critical facilities, and for some electricity utilities to help meet peak power demands and to maintain a stable electricity supply (Lead Development Association International, 2003e).

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Table 11. Total industrial lead consumption Country or region

Australia Austria Belgium Brazil Canada China Czech Republic Finland Francea Germanya India Italya Japan Mexico Netherlands New Zealand Republic of Korea Romania Scandinaviab South Africa South-East Asiac Spain Switzerland United Kingdoma USAa Total

Consumption (thousand tonnes) in year 1985

1990

1996

2001

49.5 58.0 66.8 79.6 104.5 NA NA 22.0 234.3 348.2 51.3 235.0 397.4 90.6 45.1 8.6 81.0 NA 55.6 48.2 125.2 125.3 10.5 303.2 1148.3 3688.2

45.9 65.5 67.7 75.0 71.7 NA NA 13.4 261.6 375.3 51.8 259.0 417.0 66.8 65.0 8.0 150.0 NA 36.3 65.9 185.0 126.7 8.7 334.0 1288.4 4038.7

67.0 58.0 50.6 110.0 93.4 470.1 25.0 3.5 273.8 331.0 85.0 268.0 329.9 141.0 57.0 7.0 289.8 22.0 49.0 63.1 413.0 144.0 10.5 309.2 1554.4 5225.3

41.0 59.0 40.3 112.0 71.8 700.0 80.0 2.0 282.5 392.6 127.0 283.0 284.7 205.0 30.0 5.0 314.7 20.0 13.0 59.1 427.0 246.0 12.6 266.5 1587.3 5662.1

From International Lead and Zinc Study Group (1992, 2003) NA, not available a Data for these countries include total metal usage in all forms, i.e. refined lead and alloys (lead content), plus re-melted lead recovered from secondary materials. Data for other countries include refined lead and alloys only. b Denmark, Norway and Sweden c China, Hong Kong Special Administrative Region, China (Province of Taiwan), Indonesia, Malaysia, Philippines and Singapore

Since 1960 the manufacture of lead–acid batteries has remained the largest single use of lead in nearly all countries, accounting for an ever-increasing percentage of total lead consumption (see Tables 12, 14 and 15) (International Lead and Zinc Study Group, 1992).

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Table 12. Trends in uses of lead in selected countriesa Use

Percentage of total usage in year

Batteries Cable sheathing Rolled and extruded productsb Shot/ammunition Alloys Pigments and other compounds Gasoline additives Miscellaneous Total

1985

1990

1996

2001

57.7 5.6 7.6 2.8 4.2 14.2 3.7 4.2 100.0

63.0 4.5 7.7 2.8 3.3 12.8 2.1 3.8 100.0

72.5 2.1 5.9 2.3 3.2 10.0 0.9 3.3 100.0

76.7 1.4 6.0 2.1 2.5 8.1 0.4 2.8 100.0

From International Lead and Zinc Study Group (1992, 2003) a Countries include: Australia, Austria, Belgium, Brazil, Canada, China (Hong Kong Special Administrative Region), China (Province of Taiwan), Denmark, Finland, France, Germany, India, Indonesia, Italy, Japan, Malaysia, Mexico, Netherlands, New Zealand, Norway, Philippines, Republic of Korea, Singapore, South Africa, Spain, Sweden, Switzerland, United Kingdom and USA. b Including lead sheet

Table 13. Trends in total lead consumption in six major consuming countries Country

France Germany Italy Japan United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

196 281 108 162 385 926 2058

240 342 259 347 364 1398 2950

233 342 280 368 336 1358 2917

262 375 259 417 334 1288 2935

From International Lead and Zinc Study Group (1992) The data include refined metal and direct use of lead in scrap form.

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Table 14. Trends in principal uses of lead in six major consuming countriesa Use

Percentage of total use in year

Batteries Cable sheathing Rolled/extruded products Shot/ammunition Alloys Pigment/compounds Gasoline additives Miscellaneous Total

1960

1979

1990

27.7 17.9 18.0 3.2 10.5 9.9 9.1 3.7 100.0

50.8 5.9 7.7 3.2 6.7 12.3 9.8 3.6 100.0

64.4 3.8 7.8 3.8 3.5 10.9 2.7 3.1 100.0

From International Lead and Zinc Study Group (1992) a France, Germany, Italy, Japan, United Kingdom and USA

Table 15. Trends in consumption of lead for batteries in six major consuming countries Country

France Germanya Italy Japan United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

45.0 73.2 25.5 30.0 76.2 320.4 570.3

90.0 132.9 68.0 163.1 106.5 698.0 1258.5

110.7 158.3 93.0 191.8 113.9 814.4 1481.2

163.5 195.2 113.2 294.6 103.7 1019.6 1889.8

From International Lead and Zinc Study Group (1992) a Excludes consumption by some independent producers of lead oxides for batteries.

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Table 16. Trends in consumption of lead for rolled/ extruded products in six major consuming countries Country

France Germany Italy Japan United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

43.7 44.3 29.1 35.9 88.0 130.1 371.1

31.0 31.1 50.3 39.6 57.7 90.2 299.9

27.2 32.7 40.8 26.7 48.9 47.7 224.0

22.4 39.1 21.5 10.9 98.6 35.8 228.3

From International Lead and Zinc Study Group (1992)

Table 17. Trend in consumption of lead for cable sheathing in six major consuming countries Country

France Germany Italy Japan United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

60.8 83.9 24.0 47.0 97.0 54.7 367.4

41.1 54.6 44.8 28.7 45.8 39.0 254.0

21.4 31.5 40.0 36.8 26.6 16.4 172.7

16.3 12.2 48.7 4.9 10.4 18.3 110.8

From International Lead and Zinc Study Group (1992)

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Table 18. Trends in consumption of lead for alloys in six major consuming countries Country

France Germany Italy Japan United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

17.3 22.7 6.0 7.1 37.0 125.3 215.4

14.8 22.8 6.0 24.2 35.0 128.8 231.6

9.3 16.5 5.7 18.3 24.5 120.0 194.3

3.2 9.0 3.5 18.7 22.0 46.4 102.8

From International Lead and Zinc Study Group (1992)

Table 19. Trends in consumption of lead for pigments and compounds in six major consuming countries Country

France Germany Italy Japan United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

11.9 38.4 10.1 17.2 35.9 89.3 202.8

34.5 69.6 45.2 64.2 38.8 98.7 351.0

33.0 76.8 60.4 62.4 34.1 90.8 357.5

29.4 100.3 40.0 64.0 28.6 56.5 318.8

From International Lead and Zinc Study Group (1992)

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Lead sheet

The use of lead sheet has increased dramatically over recent years, particularly for the building industry. Lead sheet has been produced for decades by traditional wide lead mills in which lead slabs are fed through large drum-like rollers, sometimes several times, to produce lead sheets of the desired thickness. The traditional wide lead mill is being replaced by more sophisticated rolling mills producing coils of lead 1.2–1.5 m wide. Most lead sheets in building applications are between 1.3 and 2.2 mm thick, but sheets of 2.6–3.6 mm are used for roofing prestige buildings. Thick sheet alloys are rolled for applications such as anodes for electrowinning and thin foils are used for sound attenuation. A manufacturing technique other than milling is continuous casting in which a rotating, water-cooled drum is partly immersed in a bath of molten lead. The drum picks up a solid layer of lead, which is removed over a knife edge adjacent to the drum as it rotates. The thickness is controlled by varying the speed of rotation and the temperature of the drum (Lead Development Association International, 2003e). In the building industry, most of the lead sheet (or strip) is used as flashings or weatherings to prevent water from penetrating, the remainder being used for roofing and cladding. By virtue of its resistance to chemical corrosion, lead sheet is also used for the lining of chemical treatment baths, acid plants and storage vessels. The high density of lead sheet and its ‘limpness’ make it a very effective material for reducing the transmission of sound through partitions and doors of comparatively lightweight construction. Often the lead sheet is bonded adhesively to plywood or to other building boards for convenience of handling. A particular advantage of the high density of lead is that only relatively thin layers are needed to suppress the transmission of sound (Lead Development Association International, 2003e). Lead sheet is the principal element in the product category ‘rolled and extruded products’. In many countries, the demand for rolled and extruded lead products declined in the 1960s and 1970s, due in part to a rapid decline in the use of lead pipe (see Tables 14 and 16). Nevertheless, in a number of countries (see Table 12), lead sheet remains the third largest use of lead at about 6% of the total reported consumption (International Lead and Zinc Study Group, 1992, 2003). 1.3.3

Lead pipes

Lead piping, once a substantial use in the ‘rolled and extruded products’ category, has been replaced progressively by copper tubes for the transport of domestic water and the supply of gas and by plastic tubing for disposal of wastewater. Lead pipes have not been used in new supplies of domestic water for about 30 years. However, due to their corrosion-resistant properties, they are still used for transport of corrosive chemicals at chemical plants. Also, lead pipe of appropriate composition is extruded for cutting into short-length ‘sleeves’ used in the jointing of lead-sheathed cables (see below) (International Lead and Zinc Study, 1992; Lead Development Association International, 2003e).

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Cable sheathing

Because of its corrosion resistance when in contact with a wide range of industrial and marine environments, soils and chemicals, lead was one of the first materials to be used to provide an impervious sheath on electric cables. Lead can be applied to the cable core in unlimited lengths by extrusion at temperatures that do not damage the most sensitive conductors (optical fibres) or insulating materials (paper or plastics). Lead is pliable and withstands the coiling, uncoiling, handling and bending operations involved in the manufacturing and installation of the cable. A lead sheath can be readily soldered at low temperatures when cables need to be jointed or new cables installed. With modern screwtype continuous extruders, unjointed submarine power cables as long as 100 km have been produced (Lead Development Association International, 2003e). Until 1960 sheathing of electrical cables was the largest single use of lead in many countries including France, Germany, Japan and the United Kingdom, representing 25–30% of total lead consumption in these four countries. It was used much less extensively in the USA where, during the late 1950s, lead was replaced by alternative materials, generally plastics, as the sheathing material for telephone cables. Since the mid-1960s, however, there has been a gradual decline in the use of lead for cable sheathing in most countries (Table 17). By 1990, lead consumption for cable sheathing had fallen to 4.5% of total consumption and, by 2001, to 1.4% (Table 12) (International Lead and Zinc Study Group, 1992, 2003). 1.3.5

Lead alloys (a)

Lead–antimony alloys

By far the largest use of lead–antimony alloys is in batteries. At one time, antimony contents of ∼10% were common, but the current generation of lead–acid batteries has a much lower antimony content. Alloys with 1–12% antimony are used widely in the chemical industry for pumps and valves, and in radiation shielding both for lining the walls of X-ray rooms and for bricks to house radioactive sources in the nuclear industry. The addition of antimony to lead increases the hardness of the lead, and therefore its resistance to physical damage, without greatly reducing its corrosion resistance (Lead Development Association International, 2003e). (b)

Solders

Soldering is a method of joining materials, in which a special metal (solder) is applied in the molten state to wet two solid surfaces and join them on solidification. Solders are classified according to their working temperatures. Soft solders, which have the lowest melting-points, are largely lead–tin alloys with or without antimony, while fusible alloys contain various combinations of lead, tin, bismuth, cadmium and other low melting-point metals. Depending on the application, lead–tin solders may contain from a few per cent to more than 60% tin.

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A substantial proportion of solder is used in electrical or electronic assemblies. The advances made in the electronics industry have required the development of fast and highly-automated methods of soldering. Printed circuit assemblies can be soldered by passing them across a standing wave of continuously-circulating molten solder (Lead Development Association International, 2003e). The use of lead solder in plumbing has declined with the replacement of lead piping by copper tubing and, more recently, as a result of concerns of potential leaching of lead into water supplies. Similarly, concerns of possible danger to health have restricted the use of lead solders in the canning industry, formerly an important market. (c)

Lead for radiation shielding

Lead and its alloys in metallic form, and lead compounds, are used in various forms of radiation shielding. The shielding of containers for radioactive materials is usually metallic lead (see above). Radioactive materials in laboratories and hospitals are usually handled by remote control from a position of safety behind a wall of lead bricks. X-ray machines are normally installed in rooms lined with lead sheet; lead compounds are constituents of the glass used in shielding partitions to permit safe viewing; and lead powder is incorporated into plastic and rubber sheeting materials used for protective clothing (Lead Development Association International, 2003e). (d)

Other uses of lead alloys

A variety of lead alloys are produced for a wide range of applications in various industries. In the 1990s, these alloys accounted for 130–150 000 tonnes of lead used in industrialized countries (Table 18). However, the trend in this sector had been one of steady decline during the previous three decades (Table 14), as some uses have been overtaken by technological changes or have been restricted by health and environmental regulations. The use of terne metal (a thin tin–lead alloy coating) for corrosion protection, and the addition of lead to brass and bronze to assist in free machining, and in bearing metals to reduce friction and wear in machinery, have declined slowly due to competition from alternative materials such as aluminum and plastics. The market for type metal in the printing industry has largely disappeared as hot metal printing has been replaced by new technology. In the USA, this use peaked at 30 000 tonnes in 1965 but had fallen to 1–2000 tonnes by the mid-1980s and is similarly low in other developed countries (International Lead and Zinc Study Group, 1992). 1.3.6

Lead pigments and compounds

The market for lead pigments and compounds constitutes the second largest use of lead after lead–acid batteries. The market peaked in the mid-1980s, when over 500 000 tonnes of lead were used in lead pigments and compounds, mainly by the plastics, glass and ceramics industries, and accounting for 14% of total lead consumption (Table 14). Since

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then these uses have been restricted by health and environmental concerns while still remaining the second largest use of lead (8% of total lead consumption) (Table 12). Besides the six major consuming countries (Table 19), pigments and compounds are also the second most important use of lead in other countries including Brazil, Canada, the Republic of Korea, South Africa, Spain and countries of South-East Asia (International Lead and Zinc Study Group, 1992, 2003). (a)

Lead pigments

The use of lead in paints for domestic purposes and in some commercial and industrial applications is now severely restricted or banned in view of the potential health risks caused by exposure to weathered or flaking paint. However, lead tetraoxide (Pb3O4) still retains some of its traditional importance for rust-inhibiting priming paints applied directly to iron and steel in view of its anti-corrosion properties, but faces growing competition from zinc-rich paints containing zinc dust and zinc chromate. The use of lead carbonate (white lead) in decorative paints has been phased out. Calcium plumbate-based paints are effective on galvanized steel. Lead chromate (yellow) and lead molybdate (red orange) are still used in plastics and to a lesser extent in paints. Lead chromate is used extensively as the yellow pigment in road markings and signs, which are now commonplace in most European countries and in North America (Lead Development Association International, 2003e). (b)

Lead stabilizers for polyvinyl chloride (PVC)

Lead compounds are used in both rigid and plasticized PVC to extend the temperature range at which PVC can be processed without degradation. In the building industry, the widespread adoption of PVC materials for corrosion-resistant piping and guttering in industrial facilities, for potable water piping (lead content, < 1%), and for windows and door frames provides a major market for lead sulfate and lead carbonate as stabilizers to prevent degrading of PVC during processing and when exposed to ultraviolet light. However, concerns over potential health hazards are limiting the use of lead in PVC water piping in some countries. Dibasic lead phosphite also has the property of protecting materials from degradation by ultraviolet light. Normal and dibasic lead stearates are incorporated as lubricants. All these compounds are white pigments that cannot be used when clear or translucent articles are required (International Lead and Zinc Study Group, 1992; Lead Development Association International, 2003e). The levels of lead in 16 different PVC pipes used for water supplies in Bangladesh were found to be in the range of 1.1–6.5 mg/g (Hadi et al., 1996). (c)

Lead in glass

Decorative lead crystal glass was developed in England in the seventeenth century. Normally added in the form of lead monoxide (PbO) at 24–36%, lead adds lustre, density and brilliance to the glass. Its attractiveness is further enhanced by decorative patterns that

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can be cut on the surface and by the characteristic ring associated with lead crystal. There is now a substantial market for a cheaper form of ‘semi-crystal’ containing 14–24% lead oxide, and such glasses are usually moulded with the decorative pattern rather than being hand-cut later. Lead is also used in optical glass (e.g. telescopes, binoculars), ophthalmic glass (e.g. spectacles), electrical glass (e.g. lamp tubing, cathode ray tubes) and radiation protection glass (e.g. for windows in remote-handling boxes, television tubes) (Lead Development Association International, 2003e). (d)

Lead for ceramics

Lead is used in a wide range of glaze formulations for items such as tableware (earthenware and china), wall and floor tiles, porcelain and sanitary-ware and electrical transistors and transducers. The lead compounds used are mainly lead monoxide (litharge, PbO), lead tetraoxide and lead silicates. The properties offered by lead compounds are low melting-points and wide softening ranges, low surface tension, good electrical properties and a hard-wearing and impervious finish. Lead compounds are also used in the formulation of enamels used on metals and glass. Another important application for lead compounds is in a range of ceramics (other than the glazes) used in the electronics industry. Typical of these are piezoelectric materials such as the lead zirconate/lead titanate range of compositions known generally as PZI. These materials have a wide range of applications, such as spark generators, sensors, electrical filters, gramophone pick-ups and sound generators (International Lead and Zinc Study Group, 1992; Lead Development Association International, 2003e). 1.3.7

Gasoline additives

Tetraethyl and tetramethyl lead have been used as anti-knock additives in gasoline, at concentrations up to 0.84 g/L, as an economic method of raising the ‘octane rating’ to provide the grade of gasoline needed for the efficient operation of internal combustion engines of high compression ratio (Thomas et al., 1999). However, increasing recognition of the potential health effects from exposure to lead has led to the reformulation of gasoline and the removal of lead additives. In addition, lead in gasoline is incompatible with the catalytic converters used in modern cars to control nitrogen oxides, hydrocarbons and other ‘smog’-producing agents. The use of lead in gasoline in the USA has been phased out gradually since the mid-1970s, and moves to phase it out in the European Community began in the early 1980s. Since 1977 in the USA and 1991 in Europe, all new cars are required to run on unleaded gasoline. By the end of 1999, forty countries or regions had banned the use of lead in gasoline (Table 20), although it is still permitted in some of these countries for certain off-road and marine vehicles and for general aviation aircraft (Smith, 2002). Numerous other countries are planning the phase-out of lead in gasoline in the near future. About 79% of all gasoline sold in the world in the late 1990s was unleaded (International Lead Management Center, 1999). The market for tetraethyl and tetramethyl lead has declined considerably (Table 21) and will continue to do so (Lead Development

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Table 20. Countries or regions that had phased out the use of lead in gasolinea by the end of 1999 Argentina Austria Bahamas Bangladesh Belize Bermuda Bolivia Brazil Canada Colombia Costa Rica Denmark Dominican Republic El Salvador

Finland Germany Guam Guatemala Haiti Honduras Hong Kong SAR Hungary Iceland Japan Luxembourg Malaysia Mexico

Netherlands New Zealand Nicaragua Norway Portugal Puerto Rico Republic of Korea Singapore Slovakia Sweden Thailand USA US Virgin Islands

From International Lead Management Center (1999) a See Section 1.3.7 for permitted uses of leaded gasoline.

Table 21. Trends in consumption of lead for gasoline additives in five major consuming countries Country

France Germany Italy United Kingdom USA Total

Consumption (thousand tonnes) in year 1960

1973

1979

1990

6.1 NA 4.8 27.1 148.6 186.6

13.5 9.4 11.8 54.4 248.9 338.0

15.1 10.8 13.0 58.9 186.9 284.7

9.8 NA 3.7 45.1 20.7 79.3

From International Lead and Zinc Study Group (1992) NA, not available

Association International, 2003e). In 2001, less than 0.5% of lead consumption was for gasoline additives (Table 12) (International Lead and Zinc Study Group, 2003). 1.3.8

Miscellaneous uses

About 150 000 tonnes of lead are employed each year in a variety of other uses, of which about 100 000 tonnes are consumed in the production of lead shot and ammunition in the major consuming countries (excluding Japan where this use is not reported

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separately). Globally, this use has remained relatively stable since the 1960s, at around 3–4% of total lead consumption (Tables 12 and 14). Lead cames have long been a feature of stained-glass windows in churches and cathedrals. They consist of H-shaped sections of lead which hold together the individual pieces of glass. They are now being used more widely in modern homes both in the traditional way and in the form of self-adhesive strips stuck on to a larger piece of glass to simulate an integral came. Lead weights for fishing have been largely phased out but lead stampings, pressings and castings are widely used for many weighting applications, for example curtain weights, wheel balance weights, weights for analytical instruments and yacht keels. Lead wool is made by scratching fine strands from the surface of a lead disc. It is used for the caulking of joints in large pipes like gas mains and in some specialty batteries. Lead-clad steel is a composite material manufactured by cold rolling lead sheet onto sheet steel that has been pretreated with a terne plate. A strong metallurgical bond is formed between the lead and the steel, which provides a material that combines the physical and chemical properties of lead with the mechanical properties of steel. Although primarily aimed at the sound-insulation market, lead-clad steel has also found use in radiation shielding and in the cladding of buildings. Lead powder is incorporated into a plasticizer to form sheets of lead-loaded plastic. This material is used to make radiation-protective clothing and aprons for the medical, scientific and nuclear industries (see Section 1.4.5.c). It also has sound-insulating properties. Lead powder is also used as the basis for some corrosion-resistant paints (see Section 1.4.6). Smaller amounts of lead are used in galvanizing, annealing and plating (International Lead and Zinc Study Group, 1992; Lead Development Association International, 2003e). 1.4

Occurrence

1.4.1

Environmental occurrence

Lead was one of the first metals used by man; there is evidence that it has been used for approximately 6000 years (Hunter, 1978). As a result, although both natural and anthropogenic processes are responsible for the distribution of lead throughout the environment, anthropogenic releases of lead are predominant. Industrial releases to soil from nonferrous smelters, battery plants, chemical plants, and disturbance of older structures containing lead-based paints are major contributors to total lead releases. Lead is transferred continuously between air, water, and soil by natural chemical and physical processes such as weathering, run-off, precipitation, dry deposition of dust, and stream/river flow; however, soil and sediments appear to be important sinks for lead. Lead is extremely persistent in both water and soil. Direct application of lead-contaminated sludge as fertilizers, and residues of lead arsenate used in agriculture, can also lead to the contamination of soil, sediments, surface water and ground water. In countries where leaded gasoline is still used,

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the major air emission of lead is from mobile and stationary sources of combustion. Besides environmental exposures, exposure to lead may arise from sources such as foods or beverages stored, cooked or served in lead-containing containers, food growing on contaminated soils, and traditional remedies, cosmetics and other lead-containing products. The ubiquity of lead in the environment has resulted in present-day body burdens that are estimated to be 1000 times those found in humans uncontaminated by anthropogenic lead uses (Patterson et al., 1991), but exposures have decreased substantially over the past 10–30 years in countries where control measures have been implemented. The estimated contributions of the common sources and routes of lead exposure to total lead intake vary from country to country and over time. In 1990, the estimated daily intake of lead from consumption of food, water and beverages in the USA ranged from 2 to 9 µg/day for various age groups and was approximately 4 µg/day for children 2 years of age and younger (ATSDR, 1999). For many young children, the most important source of lead exposure is through ingestion of paint chips and leaded dusts and soils released from ageing painted surfaces or during renovation and remodeling (CDC, 1997a; Lanphear et al., 1998). Compared with nonsmokers, smokers have an additional lead intake of approximately 6 µg/day, based on an estimated exposure of 14 µg/day and absorption of 30–50% of the inhaled lead into the bloodstream (IARC, 2004a). Lead is absorbed into the body via inhalation and ingestion and, to a limited extent, through the skin. The uptake of inhaled or ingested lead is dependent on the type of lead compound involved, particle size, site of contact within the body, acidity of the body fluid at that site, and physiological status of the individual (see Section 4.1). (a)

Natural occurrence

Lead occurs naturally in the earth’s crust in trace quantities at a concentration of approximately 8–20 mg/kg (Rudnick & Fountain, 1995; Taylor & McLennan, 1995). Metallic lead occurs in nature, but it is rare. The most important lead ore is galena (PbS). Anglesite (PbSO4), cerussite (PbCO3) and minium (Pb3O4) are other common lead minerals. Small amounts of lead reach the surface environment through natural weathering processes and volcanic emissions, thus giving a baseline environmental exposure. However, the abundant and widespread presence of lead in our current environment is largely a result of anthropogenic activity. (b)

Air and dust

Lead is released into the air by natural processes such as volcanic activity, forest fires, weathering of the earth’s crust and radioactive decay from radon (WHO, 1995). However, these natural contributions are of relatively minor consequence. The vast majority of lead in the atmosphere results from human activity. Globally, the main source of lead in air has been exhaust from motor vehicles using leaded gasoline (see also Section 1.4.1( f )). Release of lead also occurs during lead smelting and refining, the manufacture of goods, and the incineration of municipal and medical wastes (ATSDR, 1999). Almost all lead in air is bound to fine particles of less than 1 µm diameter, although some may be solubilized

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in acid aerosol droplets. The size of these particles varies with the source and with the age of the particle from the time of emission (US EPA, 1986a; WHO, 1995). Concentrations of lead in ambient air range from 76 × 10–6 µg/m3 in remote areas such as Antarctica (Maenhaut et al., 1979), to 0.2 µg/m3 in rural areas in Chile (Frenz et al., 1997) and to > 120 µg/m3 near stationary sources such as smelters (Nambi et al., 1997). Tables 22–27 show examples of lead concentrations in air and dust worldwide by geographic region. A few studies are detailed below according to the main source of airborne lead. Trends in emissions of lead in air in the USA have continued to fall since the late 1970s from both point sources (from 2.9 µg/m3 in 1979 to 0.4 µg/m3 in 1988) and urban sites (from 0.8 µg/m3 in 1979 to 0.1 µg/m3 in 1988). The large decrease in emissions from point sources resulted from the use of emission controls in industrial processes as well as automotive controls; the decrease in emissions from urban sites was primarily the result of the decreased use of leaded gasoline (ATSDR, 1999). Between 1976 and 1995, overall ambient air concentrations of lead in the USA declined by 97% (US EPA, 1996a). Lead concentrations in urban and suburban air in the USA (maximum quarterly mean concentrations) decreased between 1986 and 1995 from 0.18 µg/m3 to 0.04 µg/m3; rural air concentrations of lead during the same period were typically 3- to 5-fold lower (US EPA, 1996a). In remote sites, air lead concentrations as low as 0.001 µg/m3 have been reported (Eldred & Cahill, 1994). Urban air lead concentrations are typically between 0.15 and 0.5 µg/m3 in most European cities (WHO, 2000a). In Bulgaria, the Czech Republic, Hungary, Poland, Romania, Slovakia and Slovenia, exposure to lead is primarily through airborne lead. It is estimated that in congested urban areas 90% of this is due to leaded gasoline. In 1998, there was a wide range in use of unleaded gasoline for automobiles, from 100% in Slovakia to 5–7% in Bulgaria and Romania. Table 22 illustrates improvements in air quality during the 1990s through a concerted effort by the countries to phase out the use of leaded gasoline (Regional Environmental Center for Central and Eastern Europe, 1998). Lead concentration in the thoracic fraction of atmospheric particulate matter (PM10) — that part of the inspirable fraction that penetrates into the respiratory tract below the larynx — in the ambient air of Delhi, India, in 1998, was reported to range from 0.1 to 2 µg/m3 (Table 26). Principal component analysis identified three major sources, namely vehicle emissions, industrial emissions and soil resuspension (Balachandran et al., 2000). Samples collected from high-exposure areas of Mumbai, India, had higher lead concentrations than those collected in other high-exposure areas of the world including Beijing (China), Stockholm (Sweden) and Zagreb (Serbia and Montenegro) (Parikh et al., 1999). A recent report of the Central Pollution Control Board (2001–2002) found concentrations of lead in air in Mumbai, India, to be on the decline. In fact, the introduction of unleaded petrol reduced lead concentrations in ambient air by about half in seven sites throughout India (Central Pollution Control Board, 1998–99). In Semarang, Indonesia, mean urban airborne lead concentrations were found to be 0.35 µg/m3 in a highway zone, 0.95 µg/m3 in a residential zone (mainly due to solid-waste

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Table 22. Lead concentrations in ambient air in central and eastern Europe Country

Location

Mean concentration (µg/m3)a by year 1990

1991

1992

1993

1994

1995

0.3 0.5 0.6 1.2

0.3 0.4 0.5 1.2

0.3 0.4 0.4 1.2

0.3 0.2 0.3 0.9

0.2 0.2 0.2 0.9

0.2 0.4 0.3 0.7

1996

Bulgaria

Sofia Pernik Plovdiv Kardjali

Czech Republicb

Prague Pribram Usti n. Labem Brno Ostrava

0.06 0.08 0.06 0.07 0.05

0.04 0.06 0.04 0.08 0.08

0.01 0.02 0.03 0.05 0.05

Hungary

Budapest Pecs Miskolc Debrecen

0.20 0.42

0.22 0.44

0.56

0.30

0.22 0.25 0.18 0.27

0.19 0.21 0.12 0.28 0.58 1.00 0.16 0.55

Poland

c

0.73 2.69 0.64

0.90 0.85 0.55 1.16

1.16 0.76 0.45 1.48

0.68 0.44 0.49 0.87

0.68 0.44 0.49 0.87

0.78 0.81 0.62 1.85

Copsa Mica Bucuresti Bala Mare Medias Zlatna

30.30 60.58 5.45 10.15 22.72

21.30 60.58 8.20 21.80 27.10

16.07 70.65 97.50 7.20 10.00

42.20

18.91

15.07 4.18 14.00

16.12 9.99 9.44

12.70 7.63 13.34 14.70 11.46

Slovakia

Bratislava B. Bystrica Ruzomberok Richnava

0.11 0.11 0.14 0.50

0.09 0.09 0.05 0.53

0.11 0.08 0.06 0.46

0.10 0.05 0.03 0.14

0.05 0.03 0.04 0.14

0.06 0.03 0.02 0.21

Slovenia

Trbovlje Zagorje Hrastnik

0.90 1.50 0.25

0.70 0.70 0.45

0.30 0.30 0.10

Romania

Katowice Chorzuw Pszczyna Lodz

From Regional Environmental Center for Central and Eastern Europe (1998) Italicized text denotes short-term maximal concentration. b Annual geometric means c Maximum average daily concentration

a

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Table 23. Lead concentration in outdoor air in Latin America and the Caribbean Country

Location

Year of study

Period covered

Concentration (µg/m3) mean or range of means

Reference

Bolivia

La Paz

NR

NR

1.1

Romieu et al. (1997)

Brazil

S. Paulo Osasco S. Caetano do Sul

1985 1985 1985

Annual average Annual average Annual average

0.39 0.16 0.31

Romieu et al. (1997)

Santo Amaro, Bahia, near smelter at 526 m at 955 m

1989

4-day

S. Francisco Conde, Bahia (downwind of oil refinery)

July 1994a Jan. 1995

5-day

0.029 0.0051

Lamarao de Passé, Bahia (downwind of petrochemical complex)

July 1994 Jan. 1995

5-day

0.0162 0.0054

Itacimirim/Praia do Forte, Bahia (Atlantic air masses)

July 1994 Jan. 1995

5-day

0.0015 0.00025

San Felipe

1996

NR

0.19

Frenz et al. (1997)

NS

1990

Annual average

1.1

Romieu et al. (1997)

Colombia

Bogota

1990

3-month average

3.0

Romieu et al. (1997)

Guatemala

Tegucigalpa NS

NR 1994

NR Annual average

0.18 0.17

Romieu et al. (1997)

Honduras

NS NS

1994 1994

Annual average 3-month average

1.11 1.83

Romieu et al. (1997)

1988 1990 1994 1988 1990 1994 1995

3-month average

0.34–0.24 1.08–1.47 0.24–0.37 1.95 1.23 0.28 0.54

Romieu et al. (1997)

Chile

Mexico

Mexico City

Tavares (1990) 2.8 0.13

Annual average

24-h average

Tavares (1996a)

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Table 23 (contd) Country

Peru

Venezuela

Location

NS

Caracas

Year of study

Period covered

Concentration (µg/m3) mean or range of means

Reference

1980 1985 1990 1994 1980 1985 1990 1994

3-month average

1.8 1.9 2.2 2.1 1.7 1.5 1.6 1.7

Romieu et al. (1997)

1982 1986 1990 1994

Annual average

4.5 2.6 1.9 1.6

Romieu et al. (1997)

Annual average

NR, not reported; NS, not stated a July is in wet season whereas January is during the dry season.

Table 24. Lead concentration in indoor dust in Latin America and the Caribbean Country

Location

Year(s) of study

Source of contamination

Mexico

Cd. Juarez, Chihuahua

1974

Lead smelter < 1.6 km 1.6–4 km

Villa de la Paz

NR

Mining

955 (range, 220–5190)

Yáñez et al. (2003)

Mexico City

1983

Multiple urban

587 ± 303

Bruaux & Svartengren (1985)

Caracas (daycare centre)

1997–98

Urban

999–1707

Fernández et al. (2003)

Venezuela

NR, not reported; SD, standard deviation

Concentration (µg/g) mean ± SD or range of means

1322 ± 930 220

Reference

Ordóñez et al. (2003)

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Table 25. Lead concentrations in outdoor air and dust in Africa Country

Location

Year(s) of study

Source of contamination

Concentration (µg/m3)a mean or range of means (range)

Reference

Egypt

Cairo

1983–84

Town centre Residential/industrial Residential district Suburban district Commercial

3.0 1.3 1.4 0.6 2.2

Ali et al. (1986)

Cairo

NR

Industrial district

2

Hindy et al. (1987); Nriagu (1992)

Lagos

1981

Urban setting

770–1820 µg/gb,c

Ajayi & Kamson (1983)

1991

Urban traffic

51–1180 µg/gb

Ogunsola et al. (1994a)

Cape Town

NR

High traffic Low traffic High traffic Low traffic

1.5 (1.3–2.1) 0.8 (0.4–0.9) 2900–3620b 410–2580b

von Schirnding et al. (1991a)

KwaZulu/ Natal

1995

Industrial/highway Commercial Park/beach Residential Rural

1.84 0.86 0.56 0.44 < 0.03

Nriagu et al. (1996a)

8 cities

1993–95

Urban setting

0.36–1.1

Nriagu et al. (1996b)

Kasanda

1973–74

NR

10 (5–145)

Nriagu (1992)

Nigeria

South Africa

Zambia

Adapted from Nriagu (1992) NR, not reported a Unless specified otherwise b Lead concentrations in dust c Median values

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Table 26. Lead concentrations in outdoor air and dust in Asia Country

Location

Year(s) of study

Concentration (ng/m3) mean or range of means (range)

Reference

China

Beijing and Shanghai

1984–97

60–980

Zhang, Z.-W. et al. (1998)b

Provincial capitals Other regions Beijing Taiyuan Winter Summer

30–13 700 8–2800 21–318

China (Province of Taiwan)

Tainan

180

[Environment Protection Administration ROC (1991)]

India

Delhi

1998

100–2000

Delhi

2000 2001

590 550

Balachandran et al. (2000) Central Pollution Control Board (2001– 2002) Chatterjee & Banerjee (1999) Khandekar et al. (1984) Raghunath et al. (1997) Nambi et al. (1997)

Indonesia

Japan

490–1125 115–504

Kolkata (road dust)c

536 µg/g

Mumbai Mumbai Mumbai Industrial Rural Mumbai High-exposure area Low-exposure area Mumbai Urban Industrial Nagpur 7 cities Whole country

82–605 (31–1040) 30–440 500–120 000 110

Parikh et al. (1999) 432.4 (131–864) 268.2 (147–476) 1984–96

1996 1980 1994

Semarang Urban Industrial Tokyo and Kyoto

Parikh et al. (1999) Yang & Ma (1997)

Tripathi et al. (2001) 100–1120 1180–4120 42–65 60–310 11 000

Patel et al. (2001) Sadasivan et al. (1987) Gupta & Dogra (2002) Browne et al. (1999)

350–990 8410 1996–97

15–81

Environment Agency, Japan (1997)

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Table 26 (contd) Country

Location

Korea

Pusan Seoul Seoul Pusan

Malaysia

Year(s) of study

Concentration (ng/m3) mean or range of means (range)

Reference

1984–93 1986–94

902–1596 100–1500d 22–1070

1990

1310 (210–2870)

[Moon & Lee (1992)] Lee et al. (1994) Reviewed by Moon & Ikeda (1996) Cho et al. (1992)

Kuala Lumpur

30–462

Kuala Lumpur (urban) Kemaman (semiurban) Setiu (rural)

95 27 15

Pakistanc

Karachi

7.9–101.8 µg/g

Rahbar et al. (2002)

Philippines

Whole country

1993

600–1300

Environmental Management Bureau (1996)

Manila

1994 1994 1995

300–500 300–1200d 200–800d

Saudi Arabia

Thailand

Riyadh High traffic Residential

3200 720

Bangkok

210–390

[Hisham & Pertanika (1995)] Hashim et al. (2000)

Al-Saleh (1998)

Updated from Ikeda et al. (2000a) a Unless specified otherwise b Review of 15 reports published primarily in China between 1984 and 1997 c Lead concentration in dust d Values read from graphs References in square brackets could not be retrieved as original papers.

[Pollution Control Department (1996)]

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Monthly average concentration (ng/m3)

AMa ASDa Min Max GMa GSDa

54.9 28.0 16 110

May 56.3 23.6 < 10 100

June

July

Aug.

Sept.

Oct.

Nov.

51.1 24.3

40.3 21.1

34.9 13.9

44.2 24.9

52.4 28.0

62.2 31.5

< 10 84

< 10 81

< 10 59

11 85

12 99

16 120

Dec. 73.5 34.2 20 130

Jan. 56.5 26.6 14 100

Feb.

March

Averageb

49.5 23.0

55.3 21.3

51.3 23.1

15 77

19 87

13 81 45.0 1.78

From Environment Agency, Japan (1997) AM, arithmetic mean; ASD, arithmetic standard deviation; min, minimum; max, maximum; GM, geometric mean; GSD, geometric standard deviation a Values calculated by the Working Group; values < 10 were not included in the calculations. b Mean, standard deviation, min. and max. of local annual arithmetic means among the 16 stations

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burning) and 0.99 µg/m3 in a commercial zone. Airborne lead concentrations of 8.41 µg/m3 were recorded in an industrial area; values of this magnitude had not been reported previously in Indonesia (Browne et al., 1999). After leaded gasoline, lead mining and the smelting and refining of both primary and secondary lead are the next highest sources of lead emissions that can cause contamination of the nearby environment. The nature and extent of contamination depend on many factors, including the level of production, the effectiveness of emission controls, climate, topography and other local factors. Concentrations are usually highest within 3 km of the point source (US EPA, 1989, cited by WHO, 1995). For example, near a smelter in Santo Amaro, Bahia, Brazil, 4-day average values in 1989 of 2.8 ± 1.0 µg/m3 (range, 1.8–3.9 µg/m3) were reported 526 m from the smelter chimney in one direction and 0.13 ± 0.06 µg/m3 (range, 0.08–0.22 µg/m3) 955 m in the opposite direction (see Table 23; Tavares, 1990). A report from China found that lead concentrations in ambient air, plants and soil increased proportionally with proximity to a large primary smelter; air lead concentrations were 1.3 µg/m3 at 1000 m from the source and 60 µg/m3 at 50 m from the source (Wang, 1984). Some earlier studies have shown air pollution and soil contamination as far as 10 km from lead smelters (Djuric et al., 1971; Landrigan et al., 1975a). A survey conducted in the vicinity of three lead industries in Maharashtra, India, showed the highest measured concentration of lead in air of 120 µg/m3 in a residential area 200 m from one of the industries (see Table 26; Nambi et al., 1997). High concentrations of lead in household dust in the vicinity of lead smelters or mining activity, or from vehicles using leaded gasoline, have been reported (see Tables 24, 25 and 26). Lead concentrations in dust inside houses located in the vicinity of a lead smelter at Cd. Juarez, Chihuahua, Mexico, increased from 220 µg/g at 4 km to 1322 µg/g at less than 1.6 km from the smelter (Ordóñez et al., 2003). An international study coordinated by WHO found a mean lead concentration (± standard deviation) in indoor dust in Mexico City of 587 ± 303 µg/g, compared with 440 ± 263 µg/g and 281 ± 500 µg/g in Sweden and Belgium, respectively (Bruaux & Svartengren, 1985). In 1997–98 lead concentrations of floor dust in day-care centres in Caracas, Venezuela, ranged from 999 to 1707 µg/g (Fernández et al., 2003). Data on lead in air in South America are scarce, and refer only to total lead in suspended particles. One study of lead concentrations in incoming Atlantic air masses reaching the north-eastern Brazilian coast in 1994–95 showed concentrations of 1.5 ng/m3 during the rainy season (April–August) and of 0.25 ng/m3 during the dry season (September– March) (see Table 23; Tavares, 1996a). Biomass burning, which takes place during the dry season both for forest clearance and for agricultural purposes, can be an important source of lead in rural environments with otherwise low concentrations. Measurements in the Amazon forest during the wet season (September–March) showed lead concentrations of 0.33–0.61 ng/m3 in particles smaller than 2.5 µm and 0.26–0.50 ng/m3 in particles 2.5–10 µm in size; corresponding values during the dry season (June–September) were 0.73 ng/m3 and 0.46 ng/m3, respectively (Artaxo et al., 1990).

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Coal contains small amounts of lead, and fly ash from coal combustion and refuse incineration can leach substantial amounts of lead into ambient air (Wadge & Hutton, 1987). In an urban area of Taiwan, China, where the winter is cold, lead concentrations in air were reported to be about three times higher in winter (0.49–1.13 µg/m3) than in summer (0.12–0.50 µg/m3), due to use of lead-containing coal for heating (Yang & Ma, 1997). Surveys of lead in air in seven cities in India indicated concentrations ranging from 0.06 ± 0.02 µg/m3 in Coimbatore to 0.31 ± 0.10 µg/m3 in Kanpur (Sadasivan et al., 1987). In addition to automobile exhaust, increased fuel burning in the winter and open burning of refuse were identified as sources of lead contamination (Table 26). In contrast, lead air concentrations in Japan in 1996–97 averaged 50 ng/m3 and little seasonal variation was observed (Table 27). Lead concentrations in indoor air are affected by the presence of smokers, air conditioning and lead-painted surfaces. Two studies conducted in the Netherlands and the United Kingdom showed that air lead concentrations inside dwellings where there is no major internal lead source were highly correlated with those outside and averaged approximately 60% of those in the external air immediately outside the house (Diemel et al., 1981; Davies et al., 1987). (c)

Water

Lead enters groundwater from natural weathering of rocks and soil, indirectly from atmospheric fallout and directly from industrial sources. Lead can enter freshwater bodies from municipal sewage, from harbour activities and from lead storage sites and production plants, particularly mining and smelting. In local aquatic environments, pollution can also result from leaching of lead from lead shot, shotgun cartridges and fishing weights (WHO, 1995). The concentration of lead in surface water is highly variable depending upon the sources of pollution, the lead content of sediments and the characteristics of the system (pH, temperature). An additional and distinct hazard to the water supply is the use of lead piping or lead solder in plumbing systems. Water with low pH and low concentrations of dissolved salts (referred to as aggressive or corrosive water) can leach substantial quantities of lead from pipes, solder and fixtures (ASTDR, 1999). Lead-lined reservoirs, cisterns and water tanks can be a major source of lead contamination of drinking-water. Lead concentrations in surface water, groundwater and tap-water in different geographical regions of the world are presented in Tables 28–31. A few examples are detailed below, according to the type of water analysed. Seawater generally contains low levels of lead. It was estimated that lead concentrations in the ocean were 0.0005 µg/L in the pre-industrial era and around 0.005 µg/L in the late 1970s (US EPA, 1982). Concentrations of lead in surface water and groundwater throughout the USA typically range between 5 and 30 µg/L and between 1 and 100 µg/L, respectively, although concentrations as high as 890 µg/L have been measured (US EPA, 1986a). The mean concentration of lead measured at nearly 40 000 surface-water stations throughout the

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Argentina

La Plata river, Buenos Aires Port Fishing Club Pilcomayo river (at Potosi) Tarapaya river Cachi Mayu Ribeira do Iguape river Sao Paulo State Antofagasta (household) Drinking-water Tap-water

Bolivia

Brazil Chile Mexico Uruguay

Year of study

1989 1989 1999 1999 1999 1994 1994 1998 1983 1992

NR, not reported; max., maximum concentration (µg/L)

Source of contamination

Industry, sewage, harbour activities Mine tailings Mine tailings No specific source NR NR Lead storage site No specific source Lead pipes

Concentration (µg/L) mean (range)

28.1 (2.4–58.6) 11.3 (9.9–16.4) 1399 (911–2111) 2291 (1101–3980) 1.0 ( 0.6–1.7) < 20–70 2.8 Max. 170 2 ± 1 (1–3) 15 (0.2–230)

Reference

Verrengia Guerrero & Kesten (1994) Smolders et al. (2003)

Romieu et al. (1997) Sepúlveda et al. (2000) Bruaux & Svartengren (1985) Schütz et al. (1997)

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Table 29. Lead concentrations in fresh water, seawater and sediment in the Canary Islands, Egypt and Nigeria Country

Location

Type of water/ sediment

Concentration mean or range of means (range)

Reference

Canary Islands (Spain) Egypt

Santa Cruz

Seawater

Díaz et al. (1990)

Lake Nubia Alexandria

Nigeria

Agunpa river

Sediment Seawater Sediment River water Sediment River water Sediment

1.4–11.3 µg/L (0.42–116.9) 79 µg/g 0.05–0.7 µg/L 2–49 µg/g 1.3–46 µg/L 62–75 µg/g 0.2–17 µg/L 25–58 µg/g

Ona river

Lasheen (1987)a Abdel-Moati & Atta (1991) Mombeshora et al. (1983)

Adapted from Nriagu (1992) a Original paper was not available.

USA was 3.9 µg/L (Eckel & Jacob, 1988). Lead concentrations in surface water are typically higher in urban areas than in rural areas (US EPA, 1982). Lead concentrations in the La Plata river at two sites in Buenos Aires, Argentina, ranged from 2.4 to 58.6 µg/L at the port area and from 9.9 to 16.4 µg/L at the Fishing Club (Table 28; Verrengia Guerrero & Kesten, 1994). The Ribeira do Iguape river, in South Brazil, receiving urban and industrial effluents, showed lead concentrations between < 20 and 70 µg/L in 1994 (Romieu et al., 1997). Intensive mining and tailing releases to the Pilcomayo and Tarapaya rivers resulted in mean lead concentrations in the water of 1399 and 2291 µg/L, respectively, against 1.0 µg/L in Cachi Mayu, which had not been contaminated by specific lead sources (Smolders et al., 2003). Lead contamination of groundwater around the Hussain Sagar lake, Hyderabad, India, indicated that the source of pollution was the contaminated lake. Lead was detected at concentrations in the range of 1–28 µg/L in groundwater and 38.4–62.5 µg/L in the lake (Table 30). The concentrations were appreciably higher than those for uncontaminated fresh waters which are generally below 1 µg/L (Srikanth et al., 1993). During a 2-year study of the Nainital lake, India, the average lead contamination levels in water and sediment were 600 µg/mL and 50.0 µg/g, respectively (Ali et al., 1999). The lead content in various bodies of water in India ranged from 35 to 70 µg/L in the Eastern Ghats (Rai et al., 1996), from 350 to 720 µg/L in various lakes in Lucknow, and from 510 to 1510 µg/L in Unnao (Chandra et al., 1993). In the Gomti river, lead concentrations of 13–26 µg/L were reported (Singh, 1996) and in the Ganga river from 0.98 to 6.5 µg/L (Israili, 1991). The waters of Vasai Creek (Maharashtra, India) had concentrations of 10.5–29.5 µg/L, which was the result of contamination from 18 major industries that

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Table 30. Lead concentrations in water and sediment in Asia Concentration (µg/L)a mean or range of means (range)

Reference

Comments

India

Pilani Lucknow

88 (21–354) 33 (0–67) 35 (8–58) 6 (0–16) 20 (0–40) 24 (0–80) 12 ± 3

Kaphalia et al. (1981)

pH of water, 7.5–9.1

Cambay Kanpur villages Company Mumbai

Tube well Tap-water River Tank Tube well Tube well Drinking-water

Various cities along Ganga river

River Sediment

0.98–6.5 1.2–16.0 µg/g

5 cities along Yamuna river

River (10 samples)

0.76–8.51

Koraput (Orissa) Unnao (Uttar Pradesh)

Water stations

15 ± 1 510 ± 50 (summer) 1510 ± 150 (winter)

Various sites along Gomti river

River unfiltered filtered Lake Ground water 200–1000 m from lake 1000–2000 m from lake

Hussain Sagar lake, Hyderabad

Khandekar et al. (1984) Israili (1991)

Israili & Khurshid (1991) Chandra et al. (1993)

Singh (1996) 13–25 9–21 38.4–62.5

Highest concentration in water and sediment at Garsh Mukteshwara

Srikanth et al. (1993)

Highest concentrations at Mohan Meakin, Sultampur and Pipraghat

7–28 1–9

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Country

87

Eastern Ghats (Koraput Orrisa)

Drinking-water facilities adequate primitive absent Lake water Sediment River/sea

Nainital Vasai Creek, Maharashtra Mumbai High exposure area Low exposure area Nagpur Lucknow Darbhanga District, NorthBihar

Drinking-water

Reference

Rai et al. (1996) 54 ± 5 35 ± 5 70 ± 37 150–480 50.0 µg/g 10.5–29.5

Tap-water Well Lake and ponds 9 ponds Sediment

2.8 ± 0.8 4.5 ± 1.7 2.82 3.30 350–720 [147–1056] [72.21–240.95 µg/g]

Ali et al. (1999) Lokhande & Kelkar (1999) Parikh et al. (1999)

Patel et al. (2001) Rai & Sinha (2001) Rai et al. (2002)

Indonesia

Central Kalimantan

6 rivers 3 channels 3 lakes 1 fish pond

0.41–5.23 0.1–1.28 0.28–11.48 0.51

Kurasaki et al. (2000)

Malaysia

Klang river

1992b 1993 1994 1995 1996

28 21 18.6 25.9 8

APEC (1997)

Pakistan

Karachi

Drinking-water from household

3.1–4.3

Rahbar et al. (2002)

a b

Unless specified otherwise Year of sample collection

Comments

Data for 1996–97; highest values for water and sediment in same pond Motor boats are an important mode of transport.

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Table 30 (contd)

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Table 31. Lead concentration in drinking-water, Japan, 2001 Number [%] of samples with lead concentration (µg/L) Total

<5

5–< 10

10–< 15

≥ 15

Source water

5178

5110 [98.69]

53 [1.02]

5 [0.10]

10 [0.19]

Treated watera

5647

5536 [98.03]

84 [1.49]

14 [0.25]

13 [0.23]

From Ministry of Health, Labour and Welfare, Japan (2001) a Concentrations measured at drinking-water treatment plants Note: A drinking-water standard of < 10 µg/L lead was established in Japan as of 1 April, 2004 (Ministry of Health, Labour and Welfare, Japan, 2003).

collectively released about seven tonnes of lead per year into the creek (Lokhande & Kelkar, 1999). Among six locations along four rivers in central Kalimantan, Indonesia, the highest lead concentrations were found in the Kahayan river (5.23 and 2.09 µg/L at two sampling sites), followed by Murung river (1.71 µg/L). Of various channel, lake and pond waters (7 locations), lake Tundai was found to be by far the most contaminated with lead (11.48 µg/L), followed by channel Dablabup (1.28 µg/L) (Kurasaki et al., 2000). Surveys in Canada and the USA showed that drinking-water supplies leaving treatment plants contain 2–8 µg/L lead (US EPA, 1986a; Dabeka et al., 1987). EPA estimated that less than 1% of the public water systems in the USA have water entering the distribution system with lead concentrations above 5 µg/L. However, most lead contamination comes from corrosion by-products of lead pipes and lead-soldered joints (US EPA, 1991). A survey of 1245 drinking-water samples taken from various districts in the USA showed that average lead concentrations in water in copper, galvanized and plastic pipes were 9, 4.2 and 4.5 µg/L, respectively. These data show that even plumbing that did not use lead solder (e.g. plastic pipes) contained significant amounts of lead, primarily from the brass faucet fixtures which are used in almost all plumbing. The brass fixtures may account for approximately one-third of the lead in the first-draw water (Lee et al., 1989). Following an increased volcanic activity that resulted in the release of acid aerosols, Wiebe et al. (1991) analysed over 2000 water samples in Hawaii, USA, and found lead concentrations in drinking-water collected in catchment systems ranging from < 20 to 7000 µg/L. The use of lead pipes in Uruguay resulted in tap-water concentrations of lead ranging between 0.2 and 230 µg/L (Schütz et al., 1997). In 1983, lead concentrations in drinkingwater from an underground source in Mexico City, Mexico, ranged between 1 and 3 µg/L, in spite of the past intensive use of lead in petrol (Bruaux & Svartengren, 1985). Storage

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of minerals near urban areas in Antofagasta, Chile, resulted in concentrations of lead in household water of up to 170 µg/L in 1998 (Sepúlveda et al., 2000). Water samples collected from tube wells, tanks and taps in India showed lead concentrations that varied between 0 and 354 µg/L (Kaphalia et al., 1981). The lead concentration in drinking-water in Karachi, Pakistan, was found to be in the range of 3.08–4.32 µg/L as an arithmetic mean for each of five monitored areas (Rahbar et al., 2002). Throughout Japan, more than 98% of the drinking-water samples had concentrations below 5 µg/L (Table 31; Ministry of Health, Labour & Welfare, 2001). Gulson et al. (1997a) measured lead in household water throughout the day in an unoccupied test house in Australia. Lead concentrations in water ranged from 119 µg/L for the initial (first-draw) sample to 35–52 µg/L for hourly samples (125 mL) to 1.7 µg/L for a fully flushed sample. (d)

Sediments

Lead reaching surface waters is readily bound to suspended solids and sediments, and sediments from both freshwater and marine environments have been studied for their lead content. Sediments contain considerably higher concentrations of lead than corresponding surface waters, and provide a unique record of the history of global lead fluxes (WHO, 1995). Concentrations of lead in sediments in Africa, Asia and Latin America are summarized in Tables 29, 30 and 32, respectively. Average concentrations of lead in river sediments in the USA have been reported to be about 23 mg/kg (Fitchko & Hutchinson, 1975; US EPA, 1982). In coastal sediments a mean value of 87 mg/kg was measured (range, 1–912 mg/kg) (Nriagu, 1978; US EPA, 1982). Surface sediment concentrations of lead in Puget Sound, near Seattle, were found to range from 15 to 53 mg/kg (Bloom & Crecelius, 1987). An analysis of sediments taken from 10 lakes in Pennsylvania indicated that the lead does not principally originate from parent materials in the watershed (from the native rocks as a result of acid deposition), but rather from transport of anthropogenic lead through the atmosphere onto the soil surface and subsequent run-off of soil particulates into the lake (Case et al., 1989). The main reported sources of lead entering surface-water bodies in Latin America have been metallurgy, smelter and mining effluents, oil refineries and port activities. In Brazil, the All Saints bay showed values of 119 mg/kg in sediments at the river mouth downstream from a smelter; 176 mg/kg at the river mouth downstream from an oil refinery; and 618 mg/kg in the vicinity of metallurgical industries and an industrial port, compared with 35.7 mg/kg in an area with no specific source of lead, away from industries (Tavares, 1996a,b). Mine tailings in Bolivia were responsible for an increase in lead concentrations from 7.4 mg/kg in Cachi mayu, where no specific source of lead contamination exists, to average values of 603 mg/kg (range, 292–991 mg/kg) and 902 mg/kg (range, 761–1236 mg/kg), in sediments from the Pilcomayo river at Potosi and from the Tarapaya river,

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Table 32. Lead in sediments in Latin America and the Caribbean Country

Location

Year(s) of study

Source of contamination

Concentration (µg/g) mean (range)

Reference

Brazil

All Saints bay, São Brás All Saints bay, Mataripe river mouth All Saints bay, Aratu Port All Saints bay, Cabuçu Ribeira do Iguape river Jacareí, São Paulo

1994

Downstream from lead smelter Oil refinery

119

Tavares (1996b)

618

1994

Metallurgies, industrial port No specific source

1994

NR

(3–240)

1994

NR

(10–9100)

Pilcomayo river, Potosi Tarapaya river

1997–98

Mine tailings

Smolders et al. (2003)

1997–98

Mine tailings

Cachi mayu

1997–98

No specific source

603 (292–991) 902 (761–1236) 7.4 (3.3–9.9)

Honduras

Yojoa lake

NR

NR

371

Romieu et al. (1997)

Mexico

Gulf of Mexico coast

1983–87

NR

(0.29–90.15)

Albert & Badilloa (1991)

Uruguay

Montevideo

NR

NR

(20–160)

Romieu et al. (1997)

Bolivia

1994

1994

176

35.7 Romieu et al. (1997)

NR, not reported a Review of 7 studies at 8 sites

respectively (Smolders et al., 2003). Mean concentrations of lead in sediments from the Gulf of Mexico were found to range from 0.29 to 90.15 mg/kg (Albert & Badillo, 1991). (e)

Soil

Most of the lead released into the environment from emissions or as industrial waste is deposited in soil. Lead-containing wastes result from the processing of ores, the production of iron and steel, the various end-products and uses of lead, and the removal and remediation of lead paint (ATSDR, 1999). Lead in soil may be relatively insoluble (as a sulfate, carbonate or oxide), soluble, adsorbed onto clays, adsorbed and coprecipitated with sesquioxides, adsorbed onto colloidal organic matter or complexed with organic moieties present in soil (WHO, 1995). The soil pH, the content of humic and fulvic acids

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and the amount of organic matter influence the content and mobility of lead in soils. Since acidic conditions favour the solubilization and leaching of lead from the solid phase, acidic soils tend to have lower lead concentrations when analysed as dry soil. Acid rain promotes the release of lead into groundwater. Humic and fulvic acids can also mobilize lead, and certain complex organic molecules can act as chelators of lead (WHO, 1995). Table 33 shows some sources and amounts of lead released in soils worldwide. Tables 34, 35 and 36 summarize data on lead concentration in soils in Latin America, Africa and Asia, respectively. Background concentrations of lead in soil measured across the USA in the 1970s were estimated to be in the range of < 10–70 mg/kg (Boerngen & Shacklette, 1981). Soil samples taken at distances of 50–100 m from highways, outside the range of immediate impact from traffic emissions, usually show concentrations of lead below 40 mg/kg (WHO, 1995). Studies carried out in Maryland and Minnesota indicate that within large lightindustrial urban settings such as Baltimore, soil lead concentrations are generally highest in inner-city areas, especially where high traffic flows have long prevailed (Mielke et al., 1983, 1989); the amount of lead in the soil is correlated with the size of the city, which in turn is related to traffic density (Mielke et al., 1989; Mielke, 1991). It has been suggested that the higher lead concentrations in soil samples taken around houses in the inner city are the result of greater atmospheric lead content from the burning of leaded gasoline in cars and the washdown by rain of building surfaces to which the small lead particles adhere (Mielke et al., 1989).

Table 33. Discharge of lead in soil worldwide Source of lead

Amount released (tonnes/year)

Agricultural and food wastes Animal wastes, manure Logging and other wood wastes Urban refuse Municipal sewage sludge Miscellaneous organic wastes, including excreta Solid wastes, metal manufacturing Coal fly ash, bottom fly ash Fertilizer Peat (agricultural and fuel use) Wastage of commercial products Atmospheric fallout Mine tailings Smelter slags and wastes Total yearly discharge on land

1500–27 000 3200–20 000 6600–8200 18 000–62 000 2800–9700 20–1600 4100–11 000 45 000–242 000 420–2300 450–2600 195 000–390 000 202 000–263 000 130 000–390 000 195 000–390 000 803 090–1 818 800

From Nriagu and Pacyna (1988) Many of these discharges remain localized due to the nature of the particulate matter.

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Table 34. Lead concentrations in soils in Latin America and the Caribbean

Argentina

Buenos Aires

Chile

Ecuador

Source of contamination

Concentration (mg/kg) mean ± SD (range)

Reference

1975

NR

6–12

Romieu et al. (1997)

1980

900 m from smelter, 12 m high chimney

Tavares (1990)

1985

90 m high chimney

Jacareí, São Paolo

1994

NR

10 601 ± 14 611 (32–107 268) 4415 ± 4.4b 4812 ± 8523 (236–83 532) 2529 ± 2.9b (51–338)

Antofagasta

1998

Storage of minerals

(81–3159)

Sepúlveda et al. (2000)

1998

Upwind from storage site

(51–321)

NR

Glazing of ceramics At 1 m At 5 m At 10 m At 1 km At 2 km At 6 km Control area

29 213 ± 9458a 172 ± 26 81 ± 13 55 ± 2 19 ± 1 1.4 ± 0.1 (2.3–21)

a

Santo Amaro, Bahia

Andean village La Victoria

Mambija, San Carlos and Esmeraldas

Romieu et al. (1997)

Counter et al. (2000)

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Source of contamination

Concentration (mg/kg) mean ± SD (range)

Reference

Mexico

N and NE Mexico city irrigation districts Mexico city airport Mexico city centre Mexico city Viaducto Piedad Mexico city Estadio Azteca

1980–81

Traffic fallout

5.3 ± 1.5

Albert & Badillo (1991)

1979 1979 1979

Traffic fallout Traffic fallout Traffic fallout

(739–890) (6–107) (43–578)

1979

Traffic fallout

(2.1–2.7)

Caracas, Day-care centres

1997–98

Traffic (high flow)

Particle size, 44–62.5 µm: 113–375 Particle size, < 44 µm: 190–465 Particle size, 44–62.5 µm: 106 ± 3 Particle size, < 44 µm: 142 ± 3

Venezuela

Traffic (low flow)

NR, not reported; SD, standard deviation a Leachable lead b Geometric mean and standard deviation

Fernández et al. (2003)

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Table 34 (contd)

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Table 35. Lead concentrations in soil in Saudi Arabia and Africa Country

Location

Source of contamination

Concentration (mg/kg) mean or range of means (range)

Reference

Saudi Arabia

NR

Kenya

Nairobi

Zambia

Kasanda Kabwe Lusaka

Heavy traffic Residential City traffic Industrial area 2 km from lead smelter 5 km from lead smelter No specific

95.3 34.5 137–2196 148–4088 100–> 2400 (9862–2580) 16 (11–40)

Al-Saleh (1998) Onyari et al. (1991) Nriagu (1992) Nwankwo & Elinder (1979)

NR, not reported

Lead-based paint can also be a major source of lead in soil. In the state of Maine, USA, 37% of soil samples taken within 1–2 feet (30–60 cm) of the foundation of a building more than 30 years of age had lead concentrations > 1000 mg/kg (Krueger & Duguay, 1989). In a study of the association between the concentrations of lead in soil and in blood samples taken from children in urban and rural areas in Louisiana, USA, blood lead concentrations in children appeared to be closely associated with soil lead concentration (Mielke et al., 1997a). Three prospective studies were conducted in Boston, Baltimore and Cincinnati, USA, to determine whether abatement of lead in soil could reduce blood lead concentrations of children. No significant evidence was found that lead reduction had any direct impact on children’s blood lead concentrations in either Baltimore or Cincinnati (US EPA, 1996b). In the Boston study, however, a median soil lead reduction from 2075 mg/kg to 50 mg/kg resulted in a mean decline of 2.47 µg/dL blood lead concentration 10 months after soil remediation (Weitzman et al., 1993; Aschengrau et al., 1994). A number of factors appear to be important in determining the influence of soil abatement on blood lead concentrations in children, including the site-specific exposure scenario, the extent of the remediation, and the magnitude of additional sources of lead exposure. Children with pica — a serious eating disorder characterized by repetitive consumption of nonfood items — may be at increased risk for adverse effects through ingestion of large amounts of soil contaminated with lead. It has been estimated that an average child may ingest on average between 20 and 50 mg of soil per day through normal hand-tomouth activity, whereas a child with pica may ingest up to 5000 mg of soil per day (LaGoy, 1987). This source can contribute an additional lead intake of 5 µg/day for a toddler engaging in normal hand-to-mouth activity, and significantly more for a child demonstrating pica behaviour (ATSDR, 1999). Davis et al. (1992, 1994), using electron microprobe analysis of soil and waste rock from the mining district of Butte, Montana, USA, showed that the lead bioavailability of

Residential area of greater Kolkata Coimbatore

Coimbatore

Mongolia Philippines

Thailand

Manila

Grazing-land site

Reference

Soil (mg/kg)

Plant (mg/kg)

Smelter 50 m 500 m

170 28

29.1 1.7

Lead industries Control Lead factory

200–3454 8.6 200–46 700

145–1048 (grass) 1.42 214 ± 17 (leaf)

Sewage

Surface: 13.3–22.2 Subsurface: 10.26–19.3

Nambi et al. (1997) Chatterjee & Banerjee (1999) Duraisamy et al. (2003)

Fertilization with superphosphate and zinc sulfate

1992: 24–47.2 2000: 32.4–63.2

Kamaraj et al. (2003)

Urban Residential

92 44

Burmaa et al. (2002)

Playground contaminated control

34.5–281.5 15

Sharma & Reutergardh (2000)

Highway

5.25–14.59

Comments

Wang (1984)

0.76–6.62 (grass)

Parkpian et al. (2003)

Soil contaminated at least up to 0.5 km The highest values were found in Nov.– Dec. and the lowest in March. Fertilizer used during entire period

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Table 36. Lead concentrations in soil and plants in Asia

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these samples is constrained by alteration and encapsulation of the lead-bearing minerals (galena, anglesite, cerussite and plumbojarosite), which would limit the available leadbearing surface area. The inherent chemical properties of soil-lead adsorption sites may reduce the bioavailability of soil lead compared with that of soluble lead salts and lead compounds ingested without soil and may explain the low blood lead concentrations observed in children in this mining community. Davies (1983) calculated that uncontaminated soils in the United Kingdom have a (geometric) mean lead concentration of 42 mg/kg, with a maximum of 106 mg/kg. A study conducted in Wales, United Kingdom, in an area where lead mining began 2000 years ago and ended in the middle of the 20th century, reported concentrations of lead in garden soils 14 times higher than in uncontaminated areas (Davies et al., 1985). In Port Pirie, Australia, a community with one of the world’s largest and oldest primary lead smelters, lead concentrations in soils were found to be grossly elevated, ranging up to over 2000 mg/kg (McMichael et al., 1985). The frequency of elevated lead concentrations in the blood of pregnant women and young children in this community was also increased above that found in other communities in Australia (Wilson et al., 1986; McMichael et al., 1988). The main reported sources of lead in soil in Latin America have been from smelter activities, storage of minerals, glazing of ceramics, and leaded gasoline (Table 34). In Santo Amaro, Brazil, in 1980, lead concentrations as high as 107 268 mg/kg in soil have been found in orchards and homes around a smelter (arithmetic mean value for the area within 900 m from the smelter, 10 601 mg/kg), as a result of the use of dross as paving material around houses. At that time, the smelter had a 12-m high chimney. Five years later, after a 90-m high chimney was built, these values dropped to mean values of 4812 mg/kg (Tavares, 1990). In Antofagasta, in the north of Chile, storage of minerals resulted in lead concentrations up to 3159 mg/kg in soil around the site compared with values of 51–321 mg/kg upwind from the site (Sepúlveda et al., 2000). Analysis of soil around ceramic glazing facilities in an Andean Equadorian village showed a significant fall in lead soil concentration with distance from the baking kilns; concentrations were 29 213 mg/kg at 1 m, 55 mg/kg at 1 km and 1.4 mg/kg at 6 km from the kilns (Counter et al., 2000). In 1979, when tetraethyl lead was still added to gasoline, soil lead concentrations in Mexico City, Mexico, were determined near avenues in different parts of the city. Higher concentrations of lead were found in the north and north-west of the city, with the highest values found at the airport, ranging from 739 to 890 mg/kg. The centre of the city showed values between 6 and 107 mg/kg (Albert & Badillo, 1991). In 1980–81, agricultural soils north and north-east of the city, irrigated either directly from wastewaters or with clean water, were analysed for lead; there was no influence of irrigation on soil lead concentrations (Albert & Badillo, 1991). Soil lead concentrations in day-care centres near areas of high traffic flow in Caracas, Venezuela, ranged between 113 and 465 mg/kg, with higher values in soil particles < 44 µm (Fernández et al., 2003). In Argentina, a study of phosphate fertilizers imported from different parts of the world showed lead concentrations

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between 5.1 and 30.7 mg/kg, which could potentially increase lead concentrations in soils undergoing continuous fertilization (Giuffré de López Camelo et al., 1997). A number of studies have reported soil lead concentrations in the proximity of smelters and mining areas. A report from China found that lead concentrations in ambient air, plants and soil increased proportionally with proximity to a primary smelter: lead concentration in soil was 28.0 mg/kg at 500 m and 170 mg/kg at 50 m distance from the smelter (Wang, 1984). Concentrations of lead in soil have been found elevated in many locations in Asia (Table 36), such as in the vicinity of a lead refinery in Kolkata, India (Chatterjee & Banerjee, 1999), in sewage-affected soils (Duraisamy et al., 2003), or on a playground in Manila, Philippines (Sharma & Reutergardh, 2000). (f)

Lead in gasoline

Globally, by far the largest source of lead emissions into air has been exhaust from motor vehicles using organic lead as an anti-knock agent in gasoline (see Section 1.3.7). In motor-vehicle exhaust from leaded gasoline, > 90% of the lead emission is inorganic lead (e.g. lead bromochloride) and < 10% is alkyl lead vapour. Furthermore, alkyl lead compounds decompose in the atmosphere to lead oxides through a combination of photolysis and oxidation reactions, over a period ranging from a few hours to a few days (ATSDR, 1999). Vehicle emissions increase lead concentrations in the surrounding air, and lead compounds adhere to dust particles that settle and increase the lead content of dusts and soils, thus constituting a major source of exposure of the general population. By comparing ratios of stable lead isotopes in remote areas with those characteristic of lead from industrial sources in various regions, investigators have shown that the lead found in pristine areas such as Greenland and Antarctica originated from motor vehicle exhaust from North America (Rosman et al., 1994a) and South America (Rosman et al., 1994b), respectively. Nriagu and Pacyna (1988) estimated that in 1983 mobile sources worldwide contributed 248 000 tonnes of lead to the atmosphere. This compares with total estimated emissions to the atmosphere from all sources of 288 700–376 000 tonnes. By 1997, global emissions from leaded gasoline had been reduced to 40 000 tonnes and are still declining, as permissible lead contents of gasoline have been lowered and unleaded gasoline has replaced, or is replacing, leaded fuel in many countries (see Table 20). However, in a number of countries, leaded gasoline is still in use (see Section 1.3.7). Table 37 shows lead concentrations in gasoline over time in a number of countries worldwide. In Japan, the use of lead in gasoline had been phased out since 1974 and reached almost zero in 1983 (Friberg & Vahter, 1983). The Central Pollution Control Board in India (1998–1999) reported a 50% reduction of lead concentration in air as unleaded gasoline came into use. Leaded gasoline has been banned in India with effect from February 2000. In Pakistan, the addition of lead to gasoline was reduced in 1998–99 from 0.42 to 0.34 g/L in regular gasoline and from 0.84 to 0.42 g/L in high-octane gasoline. In 2001, a directive

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Table 37. Lead concentrations in gasoline, air and blood in adults and children worldwide Location

Population

Year(s) of study

Reference

Lead concentration in Gasoline (g/L)

Aira (µg/m3)

Blooda (µg/dL)

0.45 0.40 0.15

1.05 0.66 0.49

17.0b 14.7b 9.0b

Ducoffre et al. (1990)

Canada

Ontario

3–6 years

1984 1988 1990 1992

0.30 0.09 0.04 0.00

NR NR NR NR

11.9c (11.3–12.6)d 5.1c (4.8–5.4)d 3.6c (3.3–3.9)d 3.5c (3.1–3.8)d

Loranger & Zayed (1994); Langlois et al. (1996)

Finland

Helsinki

Children

Athens

Adults

0.35 0.14 0.00 0.80 0.40 0.22 0.15 0.14

0.33 0.095 0.007 3.2 1.76 0.91 0.7 0.43

4.8 (2.1–8.3) 3.0 (2.1–4.1) 2.6 (1.7–3.7) NR 16.0 11.8 8 5.5

Pönkä et al. (1993); Pönkä (1998)

Greece

1983 1988 1996 1979 1982 1984 1988 1993

Italy

Turin

≥ 18 years

Rural

≥ 20 years

0.6 0.6 0.4 0.3 0.11 0.00

4.7 3.1 2.8 1.4 0.53 NR

Mexico

Mexico City

0.5–3 years

1988 1989 1990 1991 1992 1993

0.2 0.2 0.18 0.08 0.07 0.06

NR NR NR NR NR NR

NR 21 15.1 (± 3.9)e NR 6.4 (± 1.7)e 4.9c (± 0.15)e (men) 3.2c (± 0.15)e (women) 12.2 14.6 9.8 8.6 9 7

Facchetti (1989); Bono et al. (1995)

Japan

1974 1980 1985 1989 1993 1977–80

Watanabe et al. (1985) Octel Ltd (1982, 1988, 1990); Driscoll et al. (1992); Mexico City Commission for Prevention and Control of Pollution (1993); Rothenberg et al. (1998)

Chartsias et al. (1986); Kapaki et al. (1998)

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99

NR

INORGANIC AND ORGANIC LEAD COMPOUNDS

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Country

Country

Location

Population

Reference

Lead concentration in Gasoline (g/L)

Aira (µg/m3)

Blooda (µg/dL)

NR

0.00

< 0.004g

3.4c

Piomelli et al. (1980)

New Zealand

Christchurch

Adults and children

Cape Town

Adults

Spain

Barcelona Tarragona

20–60 years 19–63 years 16–65 years

Trelleborg

3–19 years

0.84 0.84 0.84 0.45 0.2 0.84 0.40 0.60 0.15 0.40 0.13 0.40 0.15 0.00

NR NR NR NR NR NR NR 1.03 0.24 (0.18–0.3) 2.0 (0.97–3.26) 0.23 (0.02–0.43) NA NA NA

15.2 11.8 8.1 7.3 4.9 9.7 (3.0–16.0) 7.2 (0.62–14.1) 18.6 (6.8–38.9) 8.8 (0.9–31.8) 12.0c (± 1.8)e 6.3c (± 1.8)e 5.6c (2.7–10.4) 4.2c (1.9–8.1) 2.3c (1.0–6.7)

Hinton et al. (1986); Walmsley et al. (1988, 1995)

South Africa

1978–81 1982–83 1984–85 1989 1994 1984 1990 1984 1994 1990 1995 1979 1983 1993

Stockholm

Adults

Landskrona

3–19 years

1980 1983 1978 1982 1984 1988 1994

0.40 0.15 0.40 0.15 0.15 0.00 0.00

1.20 0.50 0.12–0.42 0.17 NA NA NA

7.7 (± 3.3)e 5.4 (± 3.3)e 6.0c (1.8–25.0) 4.8c (1.5–10.0) 4.2c (1.4–12.9) 3.3c (1.5–7.1) 2.5c (1.2–12.3)

Vaud, Fribourg

25–74 years

1984–85 1988–89 1992–93

0.15 0.10 0.05

NR NR NR

10.3c (8.0–17.2)f 7.3c (5.6–12.7)f 5.9c (4.4–10.2)f

Sweden

Switzerland

Maresky & Grobler (1993) Rodamilans et al. (1996) Schuhmacher et al. (1996a) [Stockholm Municipal Environment and Health Administration (1983)]; Strömberg et al. (1995) Elinder et al. (1986) Skerfving et al. (1986); Schütz et al. (1989); Strömberg et al. (1995)

Wietlisbach et al. (1995)

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Table 37 (contd)

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Location

Population

Year(s) of study

Reference

Lead concentration in Aira (µg/m3)

Blooda (µg/dL)

1979 1981 1984 1985 1986 1995

0.42 0.38 0.38 0.38 0.14 0.055

NR NR NR 0.48 0.24 NR

12.9c 11.4c 8.0–10.9c 9.5c 8.4c 3.1c

Quinn (1985); Quinn & Delves, 1987, 1988, 1989; Delves et al. (1996)

USA

Countrywide

1–74 years

1976 1977 1978 1979 1980 1988–91

0.465 0.394 0.349 0.306 0.30 0.00

0.97

0.71 0.49 0.07 (0.05–0.12)d

15.9 14.0 14.6 12.1 9.5 2.8c (2.7–3.0)d

Annest et al. (1983); [US EPA (1985; 1992)]; Brody et al. (1994); Pirkle et al. (1994)

1986 1989 1991

0.62 0.45 0.39

1.9 1.3 1.3

17.4 15.2 15.6

Cedeño et al. (1990); Romero (1996)

Caracas

≥ 15 years

101

From Thomas et al. (1999) with minor modifications NR, not reported References in square brackets could not be retrieved as original papers. a Arithmetic mean (range), unless stated otherwise b Median value c Geometric mean d 95% confidence interval e Standard deviation f 90% confidence interval g Detection limit

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Venezuela

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by the Government of Pakistan established a permissible limit of 0.02 g/L; most of the petrol produced in Pakistan is now lead-free (Paul et al., 2003). By 1995, six countries in Latin America and the Caribbean (Antigua and Barbuda, Bermuda, Bolivia, Brazil, Columbia, and Guatemala) had removed all lead from gasoline (Pan American Health Organization, 1997). Brazil introduced the national alcohol programme [hydrated alcohol used as fuel in a mixture with gasoline] in 1975, leading to 100% of cars running on unleaded fuel by the beginning of the 1980s. This resulted in a decrease of annual atmospheric lead concentrations from an average of 1.11 µg/m3 in 1980 to 0.27 µg/m3 in 1990 in São Paulo. Similarly, by 1994, 80% of the cars in Guatemala and 46% in Mexico ran on unleaded gasoline, reducing the annual average concentration of lead in air to 0.17 and 0.28 µg/m3, respectively. In Mexico City, the concentration was 1.95 µg/m3 in 1988 and had decreased by 86% in 1994. Between 1982 and 1990, the city of Caracas, Venezuela, showed a decrease in the annual average atmospheric lead concentrations from 4.5 µg/m3 to 1.9 µg/m3 (57.8% decrease). However, this is still higher than the value of 1.5 µg/m3 recommended by WHO and established as an air quality standard by US EPA. According to a survey carried out by the Pan American Center for Human Ecology and Health in Mexico in 1994, lead concentrations in gasoline in participating Latin American and Caribbean countries ranged from 1.32 g/L in Suriname to 0.03 g/L in Uruguay (Romieu & Lacasana, 1996; Romieu et al., 1997). Data on lead in gasoline, lead in air and blood lead concentrations of the local population in a number of countries worldwide are summarized in Table 37. An analysis of 17 published studies from five continents (Thomas et al., 1999) found a strong linear correlation between blood lead concentrations in the population and the consumptionweighted average concentration of lead in gasoline, with a median correlation coefficient of 0.94. As the use of lead in gasoline was phased out, blood lead concentrations across study locations converged to a median of 3.1 ± 2.3 µg/dL, and air lead concentrations were reduced to ≤ 0.2 µg/m3. (g)

Lead in paint

In the past, the use of lead pigments in paints was widespread, but it is now restricted in many countries. Dusting, flaking or peeling of paint from surfaces are major sources of lead contamination of surface dust and soil near houses, and contribute to the amount of lead in household dust. Exposure occurs not only through the direct ingestion of flaking and chalking paint but also through the inhalation of dust and soil contaminated with paint. Renovation and remodelling activities that disturb lead-based paints in homes can produce significant amounts of lead dust which can be inhaled or ingested. Removal of lead-based paint from surfaces by burning (gas torch or hot air gun), scraping or sanding can result, at least temporarily, in high levels of exposure for residents in these homes (ATSDR, 1999). Lead from paint can constitute the major source of lead exposure, in particular for young children, and can even make a significant contribution to blood lead concentrations in children living in areas that are highly contaminated with lead, e.g. around one of the largest lead mines in the world (Gulson et al., 1994). Consumption of

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a single chip of paint with a lead concentration of 1–5 mg/cm2 would provide greater short-term exposure than any other source of lead (US EPA, 1986a). An estimated 40–50% of occupied housing in the USA in 1986 was thought to have lead-based paint on exposed surfaces (Chisolm, 1986). Intervention programmes to reduce exposures to lead in house dust have been reported (Lanphear et al., 2000a; Galke et al., 2001; Leighton et al., 2003). In a study by Schmitt et al. (1988) in the USA, soil samples taken from around the foundations of homes with wooden exteriors were found to have the highest lead concentrations (mean, 522 mg/kg) while concentrations around homes composed of brick were significantly lower (mean, 158 mg/kg). Lead concentrations up to 20 136 mg/kg were found in soil samples taken near house foundations adjacent to private dwellings with exterior lead-based paint. A state-wide study in Minnesota, USA, found that exterior leadbased paint was the major source of contamination in severely contaminated soils located near the foundations of private residences, while lead aerosols accounted for virtually all of the contamination of soils at some distance from the houses. Contamination due to lead-based paint was found to be highly concentrated over a limited area, while lead aerosols were less concentrated but more widespread (Minnesota Pollution Control Agency, 1987). (See also Section 1.4.1(e)). Many countries have restricted the use of lead in paint. Leroyer et al. (2001) mention that lead in paint was banned in France in 1948. A lead concentration greater than 0.06% is not permitted in indoor paints sold in the USA (US DHUD, 1987). However, the lead content of paint remains unregulated in some countries (Nriagu et al., 1996b). Ten per cent of lead metal used in India was reported to be used in the manufacture of paint, and wherever such paint is used there will be the potential for human exposure to lead (van Alphen, 1999). Results of a study of lead content of paint used in India are shown in Table 38. Of the 24 samples analysed, 17 had lead concentrations ≥ 0.5%, 13 had concentrations ≥ 1% and five had concentrations ≥ 10%. The lead in these paints was predominantly in the form of lead chromates (van Alphen, 1999). (h)

Food

A major source of lead for non-occupationally exposed adults is food and drink. The amount of lead intake from food is dependent on the concentration of lead in soil, air, water and other sources. Lead present in soils is taken up by food crops. Roots usually contain more lead than stems and leaves, while seeds and fruits have the lowest concentrations. In contrast, particulate lead present in air may adhere tenaciously to leafy vegetables. Leaves collected in or near urban areas have been shown to contain substantially elevated concentrations of lead. The use of leaded gasoline or the proximity of industries producing ambient emissions of lead can greatly influence lead concentrations in foodstuff. Therefore, caution is required with regard to concentrations of foodborne lead when extrapolating between regions and countries (WHO, 1995). Typical lead concentrations in foodstuffs from some 30 countries are given in Table 39 (Galal-Gorchev, 1991a). Concentrations of lead in a variety of foodstuffs in the

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Table 38. Lead content in some paints used in India Paint coloura

Lead concentration (mg/kg)

Ultra white White primer White Brown red White Phiroza Oxford blue Phorozi Brown red Brilliant white Signal red Bus green New bus green Deep green Post office red Mint green Singal red Tractor orange Golden yellow

<1 <1 <1 1 2 3 3–6 5 5 6 16 32 40 50 60–62 61 78 114–130 168–202

Adapted from van Alphen (1999) a Paint samples from six companies in Bangalore and Chennai, India

USA, Canada, Latin America and the Caribbean, Africa, South Asia and Japan are shown in Tables 40–45, respectively. Lead concentrations of specific food items available in various countries are given in Tables 46–49. Studies from various countries on dietary lead intake by children and adults are listed in Tables 50–51. The section below presents a variety of specific sources of lead contamination in food. (i) Contamination of livestock Elevated concentrations of lead in the blood of cattle grazing near a lead smelter have been reported, although no inferences regarding lead in beef were made. Mean lead concentrations were highest in animals grazing near the smelter and decreased with increasing distance. Ingestion of soil along with the forage was thought to be the major source of lead (Neuman & Dollhopf, 1992). Evidence has been shown for transfer of lead to milk and edible tissue in cattle poisoned by licking the remains of storage batteries which had been burned and left in a pasture (Oskarsson et al., 1992). Concentrations of lead in muscle of eight acutely-sick cows that were slaughtered ranged from 0.14 to 0.50 mg/kg (wet weight basis). Normal lead concentrations in bovine meat from Sweden are < 0.005 mg/kg. Eight cows showing

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Table 39. Representative concentrations of lead in foodsa Food category

Typical lead concentration (µg/kg)

Cereals Roots and tubers Fruit Vegetables Meat Vegetable oils and fats Fish Pulses Eggs Nuts and oilseeds Shellfish Offal Spices and herbs Drinking-water Canned beverages (lead-soldered cans) Canned food (lead-soldered cans)

60 50 50 50 50 20 100 40 20 40 200 200 300 20 200 200

From Galal-Gorchev (1991a) a Data collected from 30 countries in the Global Environmental Monitoring System/Food network

Table 40. Concentrations of lead in various foods in the USA Food category

Concentration (µg/kg) range of mean

Dairy products Meat, fish and poultry Grain and cereal products Vegetables Fruit and fruit juices Oils, fats and shortenings Sugar and sweets, desserts Canned food Beverages

3–83 2–83 2–84 5–74 5–53 2–28 6–73 16–649 2–41

From US Environmental Protection Agency (1986a) Appendix 7D

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Table 41. Concentrations of lead in various foods in Canada Food category

Concentration (µg/kg) median (range)

Cereals, bread and toast (as prepared) Water consumed directly Coffee, tea, beer, liquor, sodas, etc. (as prepared) Fruit juices, fruits (canned and fresh) Dairy products and eggs Starch vegetables, e.g. potatoes, rice Other vegetables, vegetable juices and soups Meat, fish, poultry, meat-based soups Miscellaneous (pies, puddings, nuts, snack foods) Cheese (other than cottage cheese)

32.4 (11.5–78.3) 2.0 (0.25–71.2) 8.8 (< 0.05–28.9) 7.9 (1.5–109) 3.3 (1.21–81.9) 16.9 (5.5–83.7) 31.7 (0.62–254) 31.3 (11–121) 33.1 (13.6–1381) 33.8 (27.7–6775)

From Dabeka et al. (1987)

no acute symptoms of poisoning were followed for 18 weeks. The mean lead concentration in milk 2 weeks after exposure was 0.08 ± 0.04 mg/kg; the highest concentration was 0.22 mg/kg. There was an initial rapid decrease in lead concentrations in milk during the first 6 weeks after exposure, after which the concentrations remained constant or increased slightly. Lead concentration in most milk samples was < 0.03 mg/kg 6 weeks after exposure. Two cows calved at 35 and 38 weeks post-exposure. The lead concentration in the blood of the cows at the time of delivery was high, which suggests mobilization of lead during the later stages of gestation and delivery. Lead concentrations in colostrum were increased compared to those in mature milk samples taken 18 weeks after exposure (i.e. during pregnancy), but decreased rapidly after delivery in mature milk to near the limit of detection. Lead poisoning was observed in cattle and buffalo grazing near a primary lead–zinc smelter in India. Affected animals had a history of clinical signs characterized by head pressing, violent movement, blindness and salivation, and had high lead concentrations in blood (143 ± 1 µg/dL) and milk (0.75 ± 0.19 mg/L). Animals from the same pasture but without any history of clinical signs suggestive of lead poisoning had lower blood lead concentrations than the affected animals, but nonetheless higher than those reported for cattle in rural and urban areas of India (Dwivedi et al., 2001). Analysis of animal feed and meat from cattle, horse (an important food animal) and sheep in a metal-processing region (Oskemen) of eastern Kazakhstan revealed high lead concentrations in many feed and meat samples (horse > cattle > sheep). The highest concentrations of lead were found in the liver and kidney, and lower concentrations in muscle and lung. A lead concentration of 2.2 mg/kg was found in horse liver (Farmer & Farmer, 2000). Recreational and subsistence hunters consume a wide range of species including birds and mammals, some of which represent significant exposure to toxic agents, including

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Table 42. Lead concentrations in foods in Latin America and the Caribbean Concentration mean ± SD or range of means (range)

Year(s) of study

Reference

Argentina

Buenos Aires

Cultivated vegetables (leaves) White wine Red wine Vegetables

Traffic

2 mg/kg

1975

Romieu et al. (1997)

NR NR Smelter

55 ± 36 µg/L 85 ± 55 µg/L (0.01–215 mg/kg)a

NR

Roses et al. (1997)

1980

Tavares (1991)

1994

Tavares (1996b)

Cow’s milk

Oil refinery Downstream smelter No specific source Smelter

(12.0–57.9 mg/kg)a (1.36–22.5 mg/kg)a 5.30 mg/kga 0.05 (0.01–0.20 mg/L) 0.03–12 mg/kg

1994

Okada et al. (1997)

Mixed Brazil

Chile

Ecuador

Santo Amaro, Bahia All Saints Bay Mataripe (N) Såo Bras (NW) Baiacu (SW) Paraiba valley, S. Paulo Ribeira do Iguape

Mussels

NR

1994

Romieu et al. (1997)

Vegetables Potato skin

Rural areas, vulcanos

0.6–39.2 µg/kgb 94 µg/kgb

NR

Queirolo et al. (2000)

Temucho Bay Andean village: La Victoria

Vegetables

NR Glazing of ceramic

20 mg/kg

NR NR

Romieu et al. (1997) Counter et al. (2000)

NR 1972

Romieu et al. (1997) Albert & Badillo (1991)c

6.3 ± 2.0 mg/kg 119 ± 1.2 mg/kg 61.7 mg/kg (9.86–118.68 mg/kg) 23.9 mg/kg 0.75 mg/kg

Cherries Tomatoes Corn Wheat grain Kernels of wheat

Honduras Mexico

Lago Yojoa Vera Cruz, Campeche and Tabasco

Fish 4 crustaceae and 7 freshwater fish

NR Industrial region

0.30 mg/kg 0.03–5.62 mg/kg

107

Fish

Antofagasta (preAndean region)

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Concentration mean ± SD or range of means (range)

Year(s) of study

Gulf of Mexico

Oyster

NR

ND–3.0 mg/kg

1976–87

Coatzacoalcos river Laguna de Terminos

Fish Oyster

NR March–May June–October Dec–Feb

0.1–2.84 mg/kg 2.4 (0.7–4.1)a mg/kg 5.5 (5.1–5.9)a mg/kg 9.5 (8.5–10.5)a mg/kg

1983 1985–86

N and NE Mexico districts

Alfalfa Beans

NR NR

(0.4–2.5 mg/kg) (0.3–3.5 mg/kg)

1980–81

Commercially available Commercially available

Milk in different forms Canned products (fish, fruits and vegetables)

NR

5–88 µg/L

1982

NR

(ND–2.35 mg/kg)

1988

Commercially available

Canned fruits

NR

0.6–1.6 mg/kg

NR

Tamayo et al. (1984)

Trinidad and Tobago

Imported

Iodized salt

NR

6.4 mg/kg

NR

Romieu et al. (1997)

Uruguay Venezuela

Seashore States of Guarico and Portuguesa

Bivalve shell fish Rice (commercially available)

NR NR

6–32 mg/kg 0.024–0.21 mg/kg

1992 NR

Romieu et al. (1997) Buscema et al. (1997)

SD, standard deviation; NR, not reported; ND, not detectable a Dry weight b Fresh weight c Review including mainly reports and literature not easily accessible

Reference

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Table 42 (contd)

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Table 43. Lead concentrations in food in Africa (Nigeria) Food item

Lead concentration (mg/kg)

Condensed or powdered milk Beef Plantains Melon seeds Water and bitter leaf Gari flour Yam tubers

0.25–0.83 1.3 0.2 0.43 0.25–0.3 0.11 0.35

From Ukhun et al. (1990)

Table 44. Lead concentrations in foods in some Asian countries Country

Place/location

Food item

Concentration (mg/kg)a mean or range of means (range)

Reference

India

Nine localities of Greater Mumbai (high to negligible vehicle traffic)

Cereals Pulses Leafy vegetables Other vegetables Meat Fruit Milk Five brands of beer

0.23–0.56 0.54–0.88 0.47–1.12 0.042–0.16 0.40–0.46 0.032–0.044 0.16 10.4–15.7 µg/L (8.0–18.0) 0.189–0.332 (0.128–0.371) 0.21–1.47 µg/L

Khandekar et al. (1984)

Commercially available Commercially available Rajasthan Nagpur

Kazakhstan

Pakistan

4 districts around a metal production center Karachi

Rice and other cereal products Milk from cattle and buffalo Milk Infant formula Dairy Human Muscle, liver, kidney, lung Cooked food

4.13 µg/L 4.75 µg/L 2.73 µg/L 0.49–1.03 (horse) 0.86–2.22 (cattle) 0.06–1.16 (sheep) 1.25–3.90

South Asia

14 regions of south Asia

181 rice samples

0.0048–0.090 (ND–0.269)

Thailand

Grazing land site near highway

Milk

14 µg/L

ND, not detectable a Unless specified otherwise b Dry weight

b

Srikanth et al. (1995a) Srikanth et al. (1995b) Dwivedi et al. (2001) Patel et al. (2001)

Farmer & Farmer (2000) Rahbar et al. (2002) Watanabe et al. (1989) Parkpian et al. (2003)

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Table 45. Estimated lead concentrations in foods and dietary lead intake in Japan, 2001 Food category

(µg/day) Rice Other cereals and potatoes Sugar and confectionary Fat and oil Pulses and pulse products Fruits Green yellow vegetables Other vegetables and algae Beverages Fish and shellfish Meats and eggs Milk and dairy products Prepared foods Drinking-water Total

Food intakea (g/day)

Lead intake (%)

6.63 3.42 0.55 0.25 1.06 1.64 1.23 2.09 2.39 1.62 1.25 0.73 0.34 0.11

[28.4] [14.7] [2.4] [1.1] [4.5] [7.0] [5.3] [9.0] [10.3] [6.9] [5.4] [3.1] [1.5] [0.5]

23.31

[100.0]

356.3 162.6 90.7 11.3 57.2 132 93.6 175.7 509.3 94.0 113.1 170.0

Estimated lead concentrationb (µg/kg) [18.6] [21.0] [6.1] [22.1] [18.5] [12.4] [13.1] [11.9] [4.7] [17.2] [11.1] [4.3]

2042

From National Institute of Health Sciences, Japan (2000) a From Ministry of Health, Labour and Welfare, Japan (2002) b Lead intake divided by food intake

Table 46. Lead concentrations in cow’s milk and infant formula Product

Canadaa 1986 median (range) (µg/kg)

Fluid milk Evaporated milk Can Cardboard container Infant formula Ready to use, lead-solder can Ready to use, lead-free can Powder formula Powdered milkd

1.19 (0.01–2.5)

5

71.9 (27–106) –

88 9 13

30.1 (1.1–122) 1.6 (1.5–2) 6.6 (3.7–19) –

Mexicob 1982 average (µg/kg)

USAc late 1980s average (µg/kg)

10

10 1 21

Table adapted from WHO (1995) a From Dabeka & McKenzie (1987) b From Olguín et al. (1982) cited by WHO (1995) c From Bolger et al. (1991) d The concentration of lead in milk consumed by the infant will be highly dependent on the concentration of lead in water used to dilute the powdered milk.

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Table 47. Distribution of lead concentrations in table wines produced worldwidea Range of lead concentrations (µg/L)

Number of samples (n = 432)

Percentage of total samples analysed

0–10 11–25 26–50 51–100 101–250 251–500 501–673

36 62 105 144 64 12 9

8.3 14.4 24.3 33.3 14.8 2.8 2.1

From US Department of the Treasury (1991) a Wines produced in 28 different countries and commercially available in the USA

Table 48. Lead concentrations in rice consumed in various countries Country/area

China China (Province of Taiwan) Colombia Indonesia Italy Japan Malaysia Philippines Republic of Korea Saudi Arabiaa Thailand USA

Lead content (µg/kg fresh weight) N

GM

GSD

215 104 22 24 15 788 97 26 172 27 13 29

22.17 10.84 8.09 39.07 6.97 5.06 9.31 37.60 7.95 [57.5]b 8.75 7.42

2.31 3.18 2.80 2.26 3.28 2.64 2.61 2.71 1.79 [2.34]b 2.28 2.11

From Zhang et al. (1996), Al-Saleh & Shinwari (2001) GM, geometric mean; GSD, geometric standard deviation; N, no. of samples a Samples of rice imported from Australia (n = 2), Egypt (n = 2), India (n = 17), Thailand (n = 4) and USA (n = 2) b Estimated from arithmetic mean and ± arithmetic SD of 134.8 ± 285.9 mg/kg by the moment method

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Table 49. Lead concentrations in a variety of food items Location

Source

Lead concentration

Reference

Canada

Apple juice stored in glazed earthenware

65/117 samples > 7 mg/L 19/147 samples 500–1000 mg/L

Klein et al. (1970)

Ontario, Canada

Water boiled in leadsoldered electric kettle

0.75–1.2 mg/L

Ng & Martin (1977)

New York, USA

Alcoholic beverages stored in crystal containers

0.01–21.5 mg/L

Graziano & Blum (1991)

South Carolina, USA

Mourning dove

Feathers, 465.7–2011.6 µg/kg dry wt Muscle, 81.7–142.9 µg/kg wet wt Liver, 188.3–806.1 µg/kg wet wt

Burger et al. (1997)

Kuwait

Seafood (fish, shrimp)

0.06–0.16 mg/kg wet wt

Bu-Olayan & Al-Yakoob (1998)

Iowa, USA

Mexican candy wrappers

810–16 000 mg/kg

Fuortes & Bauer (2000)

lead. Wild game may be contaminated through the environment or from lead bullets ingested by or embedded in the animal (Burger et al., 1997, 1998). (ii) Contamination from food preparation, storage and tableware Lead present in food storage and serving vessels such as lead-soldered cans, ceramic dishes, cooking vessels, crystal glassware, and labels on food wrap and/or dishes can contaminate food. Acidic foods tend to leach more lead, but certain foods such as corn and beans are associated with greater release of lead than would be predicted from their acidity alone. Also, oxygen appears to accelerate the release of lead from food containers (WHO, 1995). If food is stored in ceramic or pottery-ware that is lead-glazed and fired in a low-temperature kiln, lead can migrate from the glaze into the food. The glazing process uses a flux, a material that, at high temperatures, reacts with and helps dissolve the components of the glaze. Lead oxide is commonly used as flux. Factors determining whether, and to what extent, lead will migrate include the temperature and extent of firing of the pottery during the manufacturing process, the temperature and duration of food storage, the age of the pottery and the acidity of the food. It is extremely difficult to quantify the extent of such exposures in view of variations in manufacturing processes and quality control practised in the country of origin; however, exposure can be quite significant, particularly to infants (WHO, 1995). Gersberg et al. (1997) estimated that dietary exposure to lead from beans prepared in Mexican ceramic pottery may account for the major fraction of the blood lead in children whose families use such ceramic-ware.

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Table 50. Estimated dietary lead intake in adults and children Country

Population studied

Daily intake (µg/day)a

Reference

Thailand Turkey United Kingdom

Men and women Men and women Men and women Women Women Women Women Men and women Men and women Men and women Men and women Women Women Women Men and women Women Women Men and women Women Women Men and women Men and women

USA

Men and women

230 M 96c D 43c D 46 D 24.6 19.5 15 D 66 M 54–61 6.4–76.9 140 31 D 9.3 7.0 213 M 11.3 21.5 27 M 26 D 15.1 70 110 M 71 D 83 M

Fouassin & Fondu (1980) Buchet et al. (1983) Dabeka et al. (1987) Vahter et al. (1991a) Ikeda et al. (2000a) Ikeda et al. (2000a) Vahter et al. (1991a) Varo & Koivistoinen (1983) Kampe (1983) Parikh et al. (1999) [IAEA (1987)] Vahter et al. (1991a) Ikeda et al. (2000a) Ikeda et al. (2000a) Pickston et al. (1985) Ikeda et al. (2000a) Ikeda et al. (2000a) Slorach et al. (1983) Vahter et al. (1991a,b) Ikeda et al. (2000a) [IAEA (1987)] Sherlock et al. (1983) Sherlock et al. (1983) Gartrell et al. (1985a)

15.2–23.3 14.4–19.1 225 259 316 1–2 breast milk or formula 16–17 infant formula 34 M 43 M

Raghunath et al. (1997) Raghunath et al. (1999) Olejnik et al. (1985)

Adults Belgiumb Belgiumb Canada China China (Province of Taiwan) Croatia Finland Germany India Italy Japan Malaysia New Zealand Philippines Republic of Korea Sweden

Children India

UK

6–10 years 6–10 years 0–1 year 1–3 years 7–18 years Infant

USA

< 6 months

Poland

Infant Toddler

Adapted from WHO (1995); Ikeda et al. (2000a) References in square brackets could not be retrieved as original papers. a M, market basket survey; D, duplicate diet study b Populations studied from the same region c Median value

Kovar et al. (1984) Ryu et al. (1983) Gartrell et al. (1985b)

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Table 51. Estimated respiratory and dietary intakes of lead in various cities in Asia Country, city

Route

Lead in air (ng/m3)

Intakea (µg/day)

Uptakeb (µg/day)

Total (µg/day)

Dietary/ total (%)

China, Beijing + Shanghai

Respiratory Dietary

60–540

2.70 23.1

1.35 1.16

2.50

46

Japan, Tokyo + Kyoto

Respiratory Dietary

70–81

1.13 9.0

0.57 0.68

1.24

54

Malaysia, Kuala Lumpur

Respiratory Dietary

30–462

3.69 7.0

1.85 0.53

2.37

22

Philippines, Manila

Respiratory Dietary

648

9.72 11.1

4.86 0.63

5.69

15

Thailand, Bangkok

Respiratory Dietary

210–390

4.29 15.1

2.15 1.13

3.28

34

From Ikeda et al. (2000a,b); data are on adult women and were based on studies in 1990s. a Respiration volume was assumed to be 15 m3/day. b Uptake rates are assumed to be 50% in the lungs and 5–10% in the gastrointestinal tract.

Several studies have shown contamination of foods and beverages from lead used in the manufacture or repair of metal vessels. Coating the inner surface of brass utensils with a mixture of lead and tin, described as ‘tinning’, is widely practised by artisans in India. The tin–lead alloy contains 55–70% lead. Water boiled with tamarind in a tinned brass vessel for 5 min was found to contain 400–500 µg/L lead (Vatsala & Ramakrishna, 1985). Zhu et al. (1984) described 344 cases of chronic lead poisoning in Jiansu Province, China, in people who had drunk rainwater boiled in tin kettles. After boiling, the water contained 0.79–5.34 mg/L lead. Lead concentrations have also been shown to increase when water is boiled in kettles that contain lead in their heating elements. A study in India showed that although lead leaching from pressure cookers occurs during cooking, especially from the rubber gasket and safety valve, it is only a minor source of lead in cooked food (Raghunath & Nambi, 1998). Lead-contaminated water may also contribute to foodborne lead where large volumes of water are used in food preparation and cooking, e.g. in foods prepared in boiling water. Experiments have shown that vegetables and rice cooked in water containing lead may absorb up to 80% of the lead in the water (Little et al., 1981). Trace metals, including lead, have been detected in human breast milk, thus breastfeeding could deliver lead to an infant. The reader is referred to Section 4.1.1(a)(v) for information on lead mobilisation in bones and transfer to breast milk during pregnancy and lactation. In a study in Australia, the mean lead concentration (± standard deviation) in breast milk from 21 lactating mothers was 0.73 ± 0.70 µg/kg (Gulson et al., 1998a). Analysis of 210 human milk samples taken across Canada showed a mean lead concentration

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of 1.04 µg/kg (range, < 0.05–15.8 µg/kg) (Dabeka et al., 1988). The median lead concentration in breast milk from 41 volunteers in Sweden was 2 µg/kg (range, 0.5–9.0 µg/kg) (Larsson et al., 1981), whereas the mean value for breast milk 5 days postpartum from urban residents in Germany in 1983 was 13.3 µg/L (Sternowsky & Wessolowski, 1985). The concentration in 3-day postpartum milk samples from 114 women in Malaysia averaged 47.8 µg/L (Ong et al., 1985). Concentrations of lead in human milk vary considerably depending on the mother’s exposure and occupation. Lead concentrations in the milk of a mother who had worked in a battery factory until 7 weeks before delivery decreased gradually from 19–63 to 4–14 µg/L in samples taken soon after delivery and those taken up to 32 weeks later, respectively (Ryu et al., 1978). Lead concentrations in breast milk of 96 mothers in three districts (urban, mining area and rural) of Hubei, China averaged 76, 101 and 90 µg/L (geometric mean; n = 21, 11 and 32, respectively). The concentrations were very similar in colostrum and mature milk, and correlated well with blood lead concentrations (Wang et al., 2000). Gulson et al. (1998a) measured lead isotope ratios (207Pb/206Pb and 206Pb/204Pb) in mothers’ breast milk and in infants’ blood and established that, for the first 60–90 days postpartum, the contribution from breast milk to blood lead in the infants varied from 36% to 80%. Maternal bone and diet appeared to be the major sources of lead in breast milk. Lead has also been reported in home-prepared reconstituted infant formula (breastmilk substitute). Lead concentrations in cows’ milk and infant formula analysed in Canada, Mexico and the USA are shown in Table 46. Two of forty samples of infant formula collected in a study in the Boston area of the USA had lead concentrations > 15 µg/L. In both cases, the reconstituted formula had been prepared using cold tapwater run for 5–30 sec, drawn from the plumbing of houses > 20 years old. It was concluded that three preparation practices for infant formula should be avoided: (1) excessive water boiling, (2) use of lead-containing vessels and (3) use of morning (first-draw) water (Baum & Shannon, 1997). Canning foods in lead-soldered cans may increase concentrations of lead in foods 8–10-fold. In 1974, for example, the lead concentration in evaporated milk in leadsoldered cans was 0.12 µg/g; in 1986, after these cans had been phased out, the concentration dropped to 0.006 µg/g (Capar & Rigsby, 1989). The lead content in canned foods in the USA dropped from an overall mean of 0.31 µg/g in 1980 to 0.04 µg/g in 1988 (National Food Processors Association, 1992). The production and use of three-piece lead-soldered cans ceased in 1991 in the USA. However, older lead-soldered cans may still be present in some households (ATSDR, 1999). Dabeka and McKenzie (1987, 1988) found that the intake of lead by 0–1 year-old infants fed infant formula, evaporated milk and concentrated liquid formula stored in lead-soldered cans exceeded the provisional tolerable weekly intake (PTWI) of 25 µg/kg body weight (bw) lead set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1993 (FAO/WHO, 1993). This value does not include lead in water used to prepare infant formula. Mean intakes far

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in excess of the PTWI were obtained in studies carried out in areas with high lead content in tap-water (Galal-Gorchev, 1991b). Lozeena, a bright orange powder from Iraq used to colour rice and meat, can contain 7.8–8.9% lead (CDC, 1998). Lead may leach from lead crystal decanters into the liquids they contain. Three samples of port wine with an initial concentration of 89 µg/L lead were found to have lead concentrations of 5331, 3061 and 2162 µg/L after storage for four months in crystal decanters containing 32%, 32% and 24% lead monoxide, respectively (Graziano & Blum, 1991). Lead was also found to elute from lead crystal wine glasses within minutes. Mean lead concentrations in wine contained in 12 glasses increased from 33 µg/L initially to 68, 81, 92 and 99 µg/L after 1, 2, 3 and 4 h, respectively (Graziano & Blum, 1991). [See comments on this article in de Leacy, 1991; Zuckerman, 1991]. (iii) Alcoholic beverages In addition to contamination from lead crystal glass, contamination of alcoholic beverages with lead may occur in several ways. For example, from lead solder used to repair casks or kegs and tap lines, from lead capsules used as seals on wine bottles, or from residues of lead arsenate pesticides in soils. Alcoholic beverages tend to be acidic and there is the possibility for large amounts of lead to dissolve during preparation, storage or serving (WHO, 1995). Wai et al. (1979) showed that wine can react with the lead capsule to form lead carbonate, which may dissolve in the wine during storage and pouring. In one study, lead concentrations in wine on the Swedish market ranged between 16 and 170 µg/L (Jorhem et al., 1988). The analysis of 432 table wines originating from many countries and sold in the USA is summarized in Table 47. In a study of the lead content of Argentinian wines, red wine was found to have 50% higher lead concentrations than white wine, average values being 85 and 55 µg/L, respectively (Roses et al., 1997). Sherlock et al. (1986) found that in the UK the majority of canned and bottled beer (90 and 86% respectively) contained less than 10 µg/L lead. Draught beers typically contained higher lead concentrations, with 45% having concentrations > 10 µg/L, 16% having concentrations > 20 µg/L and 4% having concentrations > 100 µg/L. The higher lead concentrations in draught beers are thought to be due to the draught-dispensing equipment which may contain brass or gunmetal, both of which contain low but significant amounts of lead. The analysis of lead concentration in five different beer brands in India showed that all brands had a mean lead concentration > 10 µg/L, with an overall mean of 13.2 µg/L. Assuming the lead concentration in beer to be 13 µg/L, the uptake of lead from beer to be 20% and consumption by three types of consumer to be 1, 5 or 10 L/week, this would result in a lead uptake of 2.6, 13 and 25 µg/week, respectively (Srikanth et al., 1995a). Illicit ‘moonshine’ whiskey made in stills composed of lead-soldered parts (e.g. truck radiators) may contain high concentrations of lead. Lead was detected in 7/12 samples of Georgia (USA) moonshine whiskey, with a maximum concentration of 5300 µg/L (Gerhardt

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et al., 1980). In a more recent study, regular consumers of moonshine whiskey (15/49 subjects) had blood lead concentrations > 50 µg/dL (Morgan et al., 2001). In general, alcoholic beverages do not appear to be a significant source of lead intake for the average person. (iv) Fish and seafood The uptake and accumulation of lead by aquatic organisms from water and sediment are influenced by various environmental factors such as temperature, salinity and pH, as well as humic and alginic acid content of the sediment. In contaminated aquatic systems, only a minor fraction of lead is dissolved in the water. Lead in fish is accumulated mostly in gill, liver, kidney and bone. In contrast to inorganic lead compounds, tetraalkyllead is rapidly taken up by fish and rapidly eliminated after the end of exposure (WHO, 1989). The Fish and Wildlife Service in the USA reported on the concentration of selected metals in 315 composite samples of whole fish collected at 109 stations nationwide in 1984–85. For lead, the geometric mean was 0.11 mg/kg (wet weight), with a maximum of 4.88 mg/kg. Lead concentrations in fish declined steadily from 1976 to 1984, suggesting that reduction in use of leaded gasoline and controls on mining and industrial discharges have reduced lead concentrations in the aquatic environment (Schmitt & Brumbaugh, 1990). Recreational and subsistence fishers consume larger quantities of fish and shellfish than the general population and frequently fish the same waterbodies routinely. Thus, these populations are at greater risk of exposure to lead and other chemical contaminants if the waters they fish are contaminated. Ingestion of lead is also a matter of concern in regular consumers of seafood produced near industrial areas such as in All Saints Bay and Ribeira do Iguape in Brazil (Tavares, 1996a,b), as well as in Uruguay (Romieu et al., 1997). (v) Rice and cereals Rice is an important source of lead intake, particularly in east and south-east Asia where rice is a staple component of the diet. Lead concentrations in rice consumed in some areas in Asia, Australia, Europe and North America are summarized in Table 48. The data show a substantial variation from < 10 to about 40 µg/kg fresh weight (Zhang et al., 1996; Al-Saleh & Shinwari, 2001a). In a study performed by Watanabe et al. (1989), rice samples were collected in 15 areas of Asia and Australia (192 samples), and in four areas in other parts of the world (15 samples). Lead concentrations were distributed log-normally, with a geometric mean ± geometric standard deviation of 15.7 ± 3.5 µg/kg and concentrations ranging from 5 µg/kg in Japan to 90 µg/kg in India. Lead in rice has been estimated to represent 28% (National Institute of Health Sciences, Japan, 2000; see Table 45), 14% (Zhang et al., 2000), 12% (Moon et al., 1995) and < 5% (Zhang et al., 1997a) of dietary lead intake in a series of studies in China, Japan and the Republic of Korea. In Japan, dietary lead intake has decreased on average from 33 µg/day in 1980 to 7 µg/day in 1990, partly as a result of a decrease in rice consumption (Watanabe et al., 1996).

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Cereals other than rice, e.g. millet and maize, may also be important sources of dietary lead. The lead concentration in these cereals (43–47 µg/kg) is higher than that in rice (20–21 µg/kg) or wheat (26–30 µg/kg) (Zhang et al., 1997b). In one study in China, lead from all cereals accounted for 26% of total dietary lead intake (Watanabe et al., 2000). Lead intake from rice in Japan was found to be 1.5 times that from wheat in 1998–2000 (Shimbo et al., 2001). The contribution of lead in rice and cereal products to the total dietary intake of lead in southern India varies among different socioeconomic groups, based on occupation and choice of consumption. It has been suggested that rice is the major source of lead among the rural and economically-deprived populations, but sources of dietary lead appeared to be more diverse in the urban middle-class and the economically-privileged (Srikanth et al., 1995b). (vi) Daily intake through food Estimates of daily dietary intakes of lead by adults and children worldwide are presented in Table 50. The available data indicate a general decrease in those areas where the concentration of lead in gasoline has decreased and those where a concerted effort has been made to avoid lead-soldered cans for food storage (Bolger et al., 1991; OECD, 1993). Similar decreases in other countries are expected to occur when similar actions to eliminate these sources of lead exposure are taken. Dietary lead intake by adult women in several Asian cities, in comparison with amounts of lead inhaled, is presented in Table 51. The ratio of dietary to total lead intake varied primarily as a reverse function of the lead concentration in atmospheric air (Ikeda et al., 2000a). In Mumbai, India, where atmospheric lead concentrations in different zones of the city varied between 82 and 605 ng/m3, the daily lead uptake by a nonsmoker living in the city area was estimated to be 33 µg, of which 75% come from food. For a suburban resident, 85% of the lead intake was estimated to come from food (Khandekar et al., 1984). (i)

Plants and fertilizers

Lead occurs naturally in plants both from deposition and uptake; there is a positive linear relationship between lead concentrations in soil and in plants. As with other environmental compartments, measurement of ‘background’ concentrations of lead in plants is complicated by the general contamination of the environment from centuries of lead use, which has included direct application of lead-containing chemicals in agriculture and contamination of fertilizers with lead (WHO, 1995). Lead has been detected in a superphosphate fertilizer at concentrations as high as 92 mg/kg (WHO, 1995). Sewage sludge, used as a source of nutrients in agriculture, may contain concentrations of lead > 1000 mg/kg; concentrations as high as 26 g/kg have been measured in the USA (WHO, 1995). In a study of soil that had received heavy sludge applications over years in the United Kingdom, the lead concentration was found to be 425 mg/kg, compared with 47 mg/kg in untreated soil (Beckett et al., 1979). Lead concentrations in grass and water plants in Asia are shown in Table 52.

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Table 52. Lead concentrations in terrestrial and aquatic plants in Asia Planta

Concentration Reference (mg/kg) mean ± SD or range of means

India

Koraput

NR

NR

Ipomea aquatic Trapa natans Trapa natans Ipomea aquatica Trapa natans Ipomea aquatica

83.3 ± 4.2 68.5 ± 2.1 54.5 ± 2.0 46.6 ± 1.5 1030.0 ± 51.5 845.0 ± 40.0

Chandra et al. (1993)

Unnao

(summer) (winter)

Eastern Ghats (Koraput, Orrisa)

NR

Local industries

Spirodela polyrrhiza Pistia stratiotes

27 ± 1.6 29 ± 0.8

Rai et al. (1996)

Mumbai

NR

Lead industries

Grass Control grass

145–1048 1.42

Nambi et al. (1997)

Lake Nainital

1997

NR

1996

Lead factory

46 ± 2.5 95 ± 4.2 37 ± 2.7 214 ± 17

Ali et al. (1999)

Residential area of greater Kolkata 4 lakes and pounds in Lucknow Pond in North-Bihar

Microcystis aeruginosa Spirogyra adnata Salix babylonica (root) Leaf samples

1998

NR

Trapa natans

75–375

1996–97

NR

Euryale ferox Salisb.

331.6–1256.6

Chatterjee & Banerjee (1999) Rai & Sinha (2001) Rai et al. (2002)

Kazakhstan

Six districts in the East

NR

Metal production centre

Hay & pasteur grasses

1.6 ± 0.01– 19.4 ± 6.2

Farmer & Farmer (2000)

Thailand

Tropical grazing land site

NR

NR

Grass

0.76– 6.62

Parkpian et al. (2003)

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NR, not reported a Names in italics are aquatic plants.

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Phytoremediation Currently, lead-contaminated soils are being remediated by a variety of engineered technologies such as isolation and containment, mechanical separation, pyrometallurgical separation, the use of permeable treatment walls, and by soil flushing and soil washing, but these methods are expensive and not feasible at all sites (Mulligan et al. 2001). Phytoremediation — the use of plants for removal of pollutants and restoration of the environment — is an emerging clean-up technology for which various reviews provide information on important aspects (Salt et al., 1995; Cunningham & Ow, 1996; Chaney et al., 1997; Salt et al., 1998). For lead remediation, phytoextraction is the more attractive and much better studied method. Phytoextraction is the uptake of metal by roots and its accumulation in the part of the plant above ground, i.e. the shoot. Plants that are capable of accumulating more metal than 0.1% of dry weight of shoot are considered to be suitable for phytoextraction. There are various reports concerning accumulation and phytoextraction of lead (Table 53). The basic problems with lead phytoextraction are the low bioavailability of lead in soil and its poor translocation from root to shoot. Of all toxic heavy metals, lead is the least phytoavailable. Water-soluble and exchangeable lead that is readily available for uptake by plants constitutes only about 0.1% of total lead in most soils (Huang et al., 1997). Soil properties influence its uptake and translocation. In addition, only a few higher plants are known to hyperaccumulate lead, mainly owing to the very low translocation of lead from the root to the shoot. Piechalak et al. (2002) demonstrated up to 95% lead accumulation in the roots of Vicia faba, Pisum sativum and Phaseolus vulgaris but only 5–10% was transported to parts above ground (see Table 53). To overcome these problems, a chelate is used to increase uptake rate and to increase lead translocation from roots to shoots. Of the many chelates, EDTA has been found to be the most appropriate. EDTA solubilizes soil lead and increases its translocation from root to shoot. It has also been shown to increase rate of transpiration, an important factor in lead phytoextraction (Wu et al. 1999). However, there are concerns about side-effects associated with chelate application. Lead EDTA easily percolates through the soil profile and causes groundwater pollution. A number of plants used in phytoremediation are crop plants (see Table 53) and thus there is a potential risk that plants grown as part of phytoremediation programmes will reenter the food chain. Furthermore, a number of algae and other plant species accumulate lead. Such species, if ingested by fish, could also re-cycle lead into the food chain. Recently, a study presented the development of a plant genetically modified to accumulate lead, which seems promising for phyto-remediation (Gisbert et al., 2003). Phytoremediation does have its limitations. It is a slower process than the traditional methods. Plants remove or degrade only small amounts of contaminants each growing season, so it can take several decades to clean up a site adequately. There are limits to plant growth such as temperature, soil type and availability of water. Lastly, most plants are

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Table 53. Lead accumulation/biosorption and detoxification by plants Plant

Treatment

Zea mays shoot

20–100 µM Pb(NO3)2 in nutrient solution

Accumulation: 400–500 mg/kg Phytoextraction: 10 600 mg/kg dw

Brassica juncea shoot

Lead concentration in soil, 2500 mg/kg; treatment with HEDTA at 2 g/kg for 7 days Lead concentration in soil, 1200–1800 mg/kg 600 mg/kg Pb: 10 mmol/kg EDTA 0.5 mmol/kg EDTA

Accumulation: 45–100 mg/kg Phytoextraction: ∼ 15 000 mg/kg 5000 mg/kg

Blaylock et al. (1997)

Lead concentration in soil, 2500 mg/kg; treatment with HEDTA at 2 g/kg for 7 days Lead concentration in soil, 0.5 mM; treatment with EDTA at 0.75 mM for 48 h

Phytoextraction: ∼ 10 000 mg/kg

Huang et al. (1997)

Phytoextraction: 11 000 mg/kg dwb

Vassil et al. (1998)

Helianthus annuus

1 mM Pb(NO3)2 in nutrient solution from emergence of 1st pair of leaves until growth of 3rd pair of leaves

Accumulation: shoot, 11 027 mg/kg dw roots, 17 149 mg/kg dw

Kastori et al. (1998)

Vicia faba

1 mM Pb(NO3)2 treatment for 96 h

46 mg/g dw (in root)

Piechalak et al. (2002)

Zea mays, Pisum sativum shoots Brassica juncea shoot

Pisum sativum Phaseolus vulgaris

Lead accumulation/ phytoextractiona

Reference

Huang & Cunningham (1996)

50 mg/g dw (in root) 75 mg/g dw (in root)

a

Accumulation refers to the natural lead uptake by the plant from soil or a nutrient solution; phytoextraction refers to lead uptake following addition of a synthetic chelating agent to the lead-contaminated soil to improve the bioavailability of the lead. b The value was 400 times higher than in untreated controls.

unable to grow on heavily-contaminated soils, thus only lightly-contaminated soils can be phytoremediated. ( j)

Others

Table 54 presents some data on lead concentrations in other sources of exposure. (i) Traditional medicine Some traditional medicines and customs have been found to result in exposure to high concentrations of lead, most of which cannot be quantified with any degree of accuracy. Rather than occurring as trace ingredients or trace contaminants, various lead compounds

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Table 54. Lead concentrations in various sources of exposure Location

Source

Lead concentration

Reference

77 000–941 000 mg/kg 0.90–72 900 mg/kg

Baer et al. (1989) Prpic-Majic et al. (1996)

Eye make-up (kohl) from Eastern Mediterranean countries

< 100–696 000 mg/kg

Parry & Eaton (1991)

Pool cue chalk Dental intraoral radiograph film storage boxes (lead oxide)

1–14 080 mg/kg 3352 µg (range, 262–34 000)a

Miller et al. (1996) CDC (2001)

Traditional remedies Arizona, USA ‘Greta’, ‘azarcon’ Zabreb, Croatia Metal-mineral tonics Cosmetics Morocco, UK, USA Others Arizona, USA Wisconsin, USA

a

Average amount of lead present on wipe samples from eight film packets stored in lead-lined boxes

are used as major ingredients in traditional medicines in numerous parts of the world (Trotter, 1990). Lead concentrations in some traditional and complementary medicines are shown in Table 55. Leaded ‘kohl’, also called ‘Al kohl’, is traditionally applied to the raw umbilical stump of the newborn in the belief of a beneficial astringent action. Lead metal and lead sulfide are used for inhalation of the fumes (‘Bokhoor’) produced from heating on hot coals, in the belief that this will ward off the devil and calm irritable infants and children (Fernando et al., 1981; Shaltout et al., 1981). An Asian remedy for menstrual cramps known as Koo Sar was reported to contain lead in concentrations as high as 12 mg/kg (CDC, 1999). The source of lead was thought to be the red dye used to colour the pills. The Hindus use as a treatment for diabetes ground seeds and roots, which were found to contain 8000 mg/kg lead (Pontifex & Garg, 1985). Latin-American countries also report the use of traditional medicines with high lead concentrations. For example, the Mexican traditional remedies ‘azarcon’ (lead tetroxide) and/or ‘greta’ (mixed lead oxides), distributed as finely ground powders, may contain more than 70% lead. They are used in the treatment of ‘empacho’, a gastrointestinal disorder considered to be due to a blockage of the intestine (Trotter, 1990). Some Chinese herbal medicines have metallic lead added to them (up to 20 000 mg/kg) to increase their weight and sale price (Wu et al., 1996). Lead contaminants also are present in some calcium supplements; 17 of 70 brands tested had lead concentrations leading to a daily intake greater than the provisional total tolerable daily intake of 6 µg (Bourgoin et al., 1993).

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Table 55. Lead concentrations in herbal and folk medicines Medicine

Concentration (µg/g)a

Saptamrut loh Keshar gugal Punarvadi gugal Trifla gugal Ghasard Bala goli Kandu Arogyavardhini Sankhvati Brahmivati Chyavan prash Trivanga bhasma Diabline bhasma Hepatogaurd Basant malti Pushap Dhanva Ras Shakti Solution Powders Tablets

5.12 2.08 1.99 4.18 16 000 25 6.7 63.2 13.0 27 500 7.30 261 200 37 770 0.4 276 to 42 573 79.3 mg/tablet 55.9 mg/tablet 5.27 µg/mL 2.6–105 200 1.0–2816.7

Prescribed for (where indicated)

Liver disease

Diabetes Diabetes Liver disease

Leg abscess Leg abscess Leg abscess

From Dunbabin et al., (1992); Nambi et al. (1997) a Unless otherwise specified

Medicinal herbs may be a potential source of lead exposure; analysis of 28 species showed lead concentrations (arithmetic mean ± arithmetic standard deviation) of 2.6 ± 0.4 mg/kg to 32.8 ± 3.1 mg/kg fresh weight (Dwivedi & Dey, 2002). (ii) Cosmetics Hair dyes and some cosmetics may contain lead compounds. Commercial hair dyes typically contain 3000–4000 mg/kg lead (Cohen & Roe, 1991). A later survey reported hair dyes formulated with lead acetate, with lead concentrations of 2300–6000 mg/kg (Mielke et al., 1997b). Lead acetate is soluble in water and easily transferred to hands and other surfaces during and following application of a hair dye product. Measurements of 150–700 µg of lead on each hand following such applications have been reported (Mielke et al., 1997b). In addition, lead is transferred by hand to mouth of the person applying the product, and to any other surface (comb, hair dryer, outside of product container, counter top) that comes into contact with the product. A dry hand passed through dry hair dyed with a lead-containing cream has been shown to pick up about 280 µg lead (Mielke et al., 1997b).

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Some traditional eye cosmetics produced locally may contain lead compounds, and their application, also to children, may result in lead exposure. Sprinkle (1995) reported blood lead concentrations of 9–24 µg/dL in nine children aged 3 months–5 years receiving daily application of such cosmetics, whereas concentrations of 2–6 µg/dL were found in nine children aged 1–6 years who had no or unknown application. Patel et al. (2001) also reported elevated blood lead concentrations (20.2 ± 13.0 µg/dL) in 45 children aged 6 months–6 years in India who used eye cosmetics daily. Cosmetics used by Chinese opera actors may also contain lead (Lai, 1972). (iii) Ammunition Use of lead ammunition may result in exposure to lead dust, generated during gun or rifle discharge, at concentrations up to 1000 µg/m3 (Elias, 1985), from lead pellets ingested by or embedded in animals that are used as food source (Burger et al., 1997), and from lead pellets embedded in humans from shooting incidents (Manton, 1994; IARC, 1999). Firing-range instructors and employees may be exposed to high concentrations of lead and may show elevated blood lead concentrations (see Section 1.4.3.e). (iv) Miscellaneous Cigarette tobacco contains 2–12 µg of lead per cigarette (IARC, 2004a); the mean concentration of lead in filter-tipped cigarettes produced between 1960 and 1980 was 2.4 mg/kg. Up to 6% of lead may be inhaled, while the remainder is present in the ash and sidestream smoke (IARC, 2004a). Smoking a pack of 20 cigarettes per day, with 12 µg lead per cigarette, and inhaling 6% of the smoke, would result in daily exposure to 14 µg lead. So-called recreational drug users who ‘sniff’ leaded gasoline vapours are at risk of toxic effects from organolead compounds as well as the hydrocarbon components of gasoline (Edminster & Bayer, 1985). A lead poisoning hazard for young children exists in certain vinyl miniblinds that have had lead added to stabilize the plastic. Over time, the plastic deteriorates to produce lead dust that can be ingested when the blinds are touched by children who then put their hands in their mouths (Consumer Product Safety Commission, 1996; Norman et al., 1997; West, 1998). (k)

Blood lead concentrations from specific sources of exposure

Blood lead concentrations resulting from exposure to a variety of specific sources, reported mainly as case reports, are presented in Table 56. 1.4.2

Exposure of the general population

Blood lead concentration is the most commonly used estimate of exposure to lead in the general population. Numerous reports show blood lead concentrations declining over time in many parts of the world, thereby validating global efforts to reduce lead exposures.

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Table 56. Blood lead concentrations from various sources of exposure Source

Blood leada (µg/dL) individual values or rangea

Reference

Burning of newspapers in fireplace Dust at home from workers’ clothing Dust on clothes from occupational exposure Dust from removal of lead-based paint Tile-glazing activities

35 Mean, 41.6–73.3

Perkins & Oski (1976) Baker et al. (1977)

31–36

Gerson et al. (1996)

20–> 80

CDC (1997a)

Median, 60 (range, 12–106)

Vahter et al. (1997)

Lead-bearing cocktail glasses

131–156

Dickinson et al. (1972)

Ontario, Canada

Water heated in leadsoldered electric kettles

35–145

Ng & Martin (1977)

Seattle, USA

Ceramics from southern Italy

74 and 144

Wallace et al. (1985)

Nablus district, Israel

Contaminated flour

Mean, 80–122 (range, 42–166)

Hershko et al. (1989)

Vancouver, Canada

Water heated in a leadsoldered electric kettle

147–154

Lockitch et al. (1991)

Hungary

Contaminated paprika (lead tetraoxide)

18.8–213

Kákosy et al. (1996)

Vermont, USA

Apple cider prepared in lead-soldered evaporator

33–40

Carney & Garbarino (1997)

California, USA Michigan, USA

Tamarindo candy Lozeena (powdered food colouring) Moonshine whiskey

26–59 25–84

CDC (1998) CDC (1998)

> 50b

Morgan et al. (2001)

Tamarindo candy and/or folk remedies

22–88

CDC (2002)

Location

Air dust New York, USA New York, USA California, USA New York, USA La Victoria and El Tejar, Ecuador Food/food containers Hawaii, USA

Georgia, USA California, USA

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Table 56 (contd) Location

Source

Blood leada (µg/dL) individual values or rangea

Reference

Traditional remedies California, USA

Azarcon

27–45

CDC (1981)

Minnesota, USA Saudi Arabia

‘Pay-loo-ah’ Traditional remedies

60 134–277

Guadalajara, Mexico

Azarcon (lead tetraoxide)

California, USA

Indian herbal medicine

Blood, 29.6; urine, 49.4 µg/L 71–80

CDC (1983) Abu Melha et al. (1987) Cueto et al. (1989)

California, USA

Azarcon, greta

20–86

New York, USA

Contaminated hai ge fen (clamshell powder)

76

Zagreb, Croatia

2.6–92.1

Connecticut, USA

Ayurvedic metal-mineral tonics ‘Koo Sar’ pills (Asian remedy for menstrual cramps)

Australia

Herbal remedy

Mother, 108; newborn, 244

Tait et al. (2002)

Surma

Mean, 34.2

Ali et al. (1978)

Traditional eye cosmetics (surma, kohl, alkohl)

Mean, 12.9

Sprinkle (1995)

Old gunshot wound

353

Dillman et al. (1979)

Blood, 40–525; urine, 55–720 µg/L

Linden et al. (1982)

Florida, USA

Retained projectiles (bullets, shrapnel, buckshot) Ingestion of 206 bullets

391

McNutt et al. (2001)

Saskatchewan, Canada

Air rifle pellets

35–56

Treble & Thompson (2002)

Cosmetics Nottingham, United Kingdom California, USA Ammunition Texas, USA Texas, USA

42–44

Smitherman & Harber (1991) CDC (1993) Markowitz et al. (1994); Hill & Hill (1995) Prpic-Majic et al. (1996) CDC (1999)

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Table 56 (contd) Location

Source

Blood leada (µg/dL) individual values or rangea

Reference

Others Oregon, USA

Curtain weight

238

Maningrida, Australia

Petrol sniffing

42–92

Blank & Howieson (1983) Eastwell et al. (1983); Watson (1985)

Australia

Petrol sniffing

105

Burns & Currie (1995)

New York, USA

Ornamental clothing accessory

144–150

Esernio-Jenssen et al. (1996)

Hospital nurseries in the USA

Blood transfusions

Mean, 3.5 (range, 2–7)

Bearer et al. (2000, 2003)

a b

Unless stated otherwise Blood lead concentration in 15/38 patients

Representative data on blood lead concentrations are presented by region in Tables 57–64, and in the text by population subgroup: adults, pregnant women and neonates, and children. (a)

Adults

The UNEP/WHO Global Study to assess exposure to lead and cadmium through biological monitoring was one of the first international reliable studies with quality assurance. The geometric mean concentration of lead in blood in different populations ranged from 6 µg/dL in Beijing (China) and Tokyo (Japan) to 22.5 µg/dL in Mexico City (Mexico). The values were below 10 µg/dL in Baltimore (USA), Jerusalem (Israel), Lima (Peru), Stockholm (Sweden) and Zagreb (Serbia and Montenegro), and between 10 and 20 µg/dL in Brussels (Belgium) and Ahmedabad, Bangalore and Kolkata (India) (Friberg & Vahter, 1983). Data from central and eastern Europe show relatively high levels of background exposure to lead at the time of the dissolution of the former Soviet Union (Table 57). There have been concerted efforts to lower exposure by phasing out the use of leaded gasoline and by controlling emissions from industries (Regional Environmental Center for Central and Eastern Europe, 1998). In the USA, the extent of recent exposures to lead in the general population has been estimated based on blood lead measurements from the National Health and Nutrition Examination Surveys (NHANES). Geometric mean blood concentrations in adults aged

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Table 57. Lead concentrations in blood in adults and children in central and eastern European countries Country

City or area

Year(s) of study

Population

Blood lead (µg/dL) mean or range

Bulgaria

Momchilgrad Momchilgrad Krichim Kurtovo Konare Haskovo Haskovo Nationwide

1991 1991 1991 1991 1995 1995 1995–96

Children, 5–7 years old Teenagers, 12–14 years old Children Children and teenagers Children, 5–7 years old Teenagers, 11–12 years old Adults (men+women)

11.4 11.6 9.2 17.0 10.1 11.4 15

Czech Republic

Pribram

1992–94

Children, 1–3 years old Children, 4–7 years old Children, 8–11 years old Teenagers, 12–14 years old

14.66; 6.61; 4.95a 10.2; 4.95; 4.67 12.50; 5.37; 4.51 7.21; 4.84; 4.69

Hungary

Budapest Sopron Local National Budapest

1992 1993 1994 1995 1996

– – – – –

11.9 11.6 7.4 6.26 6.5

Poland

Five towns with no industrial lead emitters

1992–94

Men Women Children

4.25–7.68 2.38–4.83 2.39–6.23

Based in the vicinity of zinc and copper mills

1992–94

Men Women Children

9.85–15.90 4.94–10.50 7.37–11.40

Romania (six areas of Bucharest)

North Railway Station Balta Alba Center Giurgiuhu Militari Pantelimon

1983–85 1983–85 1983–85 1983–85 1983–85 1983–85

Children Children Children Children Children Children

17.1 18.40 20.20 21.93 17.84 20.51

Slovakia

Bratislava Middle Slovakia North Slovakia

1993 1995 1996

Children Children Children

3.65 4.5 3.04

From the final report of the National Integrated Program on Environment and Health Project (1995), presented in Regional Environmental Center for Central and Eastern Europe (1998) –, not stated a Geometric mean values for subjects living at distances from the lead smelter of less than 3 km, 3–5 km, and over 5 km, respectively

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Table 58. Lead concentrations in blood in adults and children in the USA Years of survey

Population

No. of subjects

Average age (years)

Smokers

Blood lead (µg/dL) Reference GM

95% CI 12.7–13.7

Pirkle et al. (1994)

2.8–3.2

Pirkle et al. (1994)

1.67–1.83 14.2–15.8

1976–80

Men + women

5537

20–74

Included

13.1

1988–91

Men + women

6922

20–74

Included

3.0

1999–2000 1978–80

Men + women Children

4207 2271

≥ 20 1–5

Included –

1.8 15.0

1988–91

Children

2234

1–5



3.6

3.3–4.0

1991–94

Children

2392

1–5



2.7

2.5–3.0

CDC (2003a) Pirkle et al. (1994) Pirkle et al. (1994) CDC (1997b)

1999–2000

Children

723

1–5



2.2

2.0–2.5

CDC (2003a)

a

GM, geometric mean; CI, confidence interval

20 years or older have declined by 87% from 13.1 µg/dL in 1976–80 to 1.75 µg/dL in 1999–2000 (Table 58). Concentrations were higher in men than in women, and higher in Mexican-Americans and non-Hispanic blacks than in non-Hispanic whites. In general, blood lead concentrations in adults increase slowly with age (Pirkle et al., 1994; CDC, 1997b, 2003a). Lead concentrations in the general population in several countries in Africa are summarized in Table 59. Most values were > 10 µg/dL, except for two rural areas in South Africa (Grobler et al., 1985; Nriagu et al., 1997a). Reports from several Asian countries of blood lead concentrations in adults with no known occupational exposure to lead and no exposure to heavy traffic are summarized in Table 60. The values were mostly < 10 µg/dL, and few were above 13 µg/dL, with the exception of one concentration of 24 µg/dL for a rural population in Pakistan (Khan et al., 1995). One study used urinary lead concentrations to monitor lead exposure in Japan. A substantial decrease in urinary lead was reported over the last 13 years. The amounts of lead excreted (geometric means) in 24-h urine samples were 4.74, 2.67 and 1.37 µg for men in 1985, 1993 and 1998, respectively, and 3.21, 2.14 and 1.02 µg for women in the same years (Jin et al., 2000). Blood lead concentrations in adults in Australia are summarized in Table 61. As observed in other parts of the world, concentrations have declined in the general population over the past two decades.

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Table 59. Lead concentrations in blood in the general population in some countries in Africa Country

City/area

Population/ age range

Egypt

Urban area Rural area

Adults

Cairo

No lead exposure

Ibadan

Men Women

NR

Adults

Kaduna

1–6 years

Urban area Rural area

Children Children

Remote area

14–16 years

Cape Town

1st year-grade

Cape Town

Nigeria

South Africa

No. of subjects

Blood lead (µg/dL) mean (range)

Reference

17.0–36.0 14.0–25.0

Kamal et al. (1991)

18.2

Kamal et al. (1991)

11.4 12.3

Omokhodion (1984)

24

12.9 ± 7.0 (1.7–32.5)

Ogunsola et al. (1994b)

87

10.6 (max. 39)

Nriagu et al. (1997b)

22 11

[von Schirnding & Fuggle (1984)]

3.4 ± 1.5 (0.5–7.5)

Grobler et al. (1985)

200

12 (white) 18 (mixed)

von Schirnding et al. (1991a)c

1st year-grade

104

18b

von Schirnding et al. (1991b)c

Cape Province Mining village Village 40 km from mining area

Children Children Children

NR NR NR

14–16 16 13

Nriagu et al. (1996b)

Besters Valamehlo (rural)

3–5, 8–10 years

10 3.8

Nriagu et al. (1997a)

Johannesburg

6–9 years

433

11.9 (6–26)

Mathee et al. (2002)

Urban areas

Children

NR

15

Harper et al. (2003)a

NR 50

NR NR 30

1200 660

Updated from Nriagu et al. (1996b); reference in square brackets could not be retrieved as original papers. NR, not reported a Review of several published studies b Median value c [It was not clear to the Working Group whether the two articles presented data from the same study population.]

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Table 60. Lead concentrations in blood in adults in the general population in Asia

China

Shanghai 3 areas Hubei

1986–88 1993–97 NR

Women Women Women urban mining area rural ≥ 15 years of age Men Women

No. of subjects

Smoking status

Blood lead (µg/dL) arithmetic meana (range)

Reference

NR Nonsmoker

14.1 4.6b

Jiang et al. (1992) Zhang et al. (1999) Wang et al. (2000)

33 28 44 8828 1471 1332

NR NR NR NR Included Included

6.7 6.7 5.3 7.7 (ND–69.1) 7.3 5.7

200 73 100 500

Included Included Included NR

13.8 17.9 10.7 14.3 (13.0–15.7)

Friberg & Vahter (1983)

165 250

Province of Taiwan

1991–94 1993–94

Ahmedabad Bangalore Kolkata Slums of Lucknow

NR

Men + women

1994–95

Women

Indonesia

Bandung

1983

Rural men

20

NR

12

Suzuki (1990)

Iraq

Bassora

NR

Men

60

NR

14.6

Mehdi et al. (2000)

Japan

Kanagawa NR

1991 NR 1991–93

62 70 68 72

NR NR NR Nonsmoker

1.0 (0.6–2.4) 11.0 (5.0–17.2) 6.4 (3.8–11.4) 3.2b

Arai et al. (1994) Oishi et al. (1996a)

Kyoto, Sendai & Tokyo 30 sites NR

Adults Men Women Women

1991–98 NR

Women Women

607 70

Nonsmoker NR

1.9b 6.4 (3.8–11.4)

Shimbo et al. (2000) Nomiyama et al. (2002)

Irbid City

NR

Men

NR

5.7b

Hunaiti et al. (1995)

India

21

Awasthi et al. (1996; 2002)

Zhang et al. (1999)

131

Jordan

Liou et al. (1996) Chu et al. (1998)

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Country

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Population

Pakistan

Rural area

1994–95

Men

Philippines

Manila

1999

Republic of Korea

NR Chonan

Thailand

United Arab Emirates

Smoking status

Blood lead (µg/dL) arithmetic meana (range)

Reference

36

NR

24.1

Khan et al. (1995)

Men + women

50

NR

12.6

Suplido & Ong (2000)

NR 1997–99

NR Men + women

26 135

NR 87% current

10.8 5.3 (2–10)

Kim et al. (1995a) Lee, S.-S. et al. (2001); Schwartz et al. (2001)

Bangkok NR Chaiyapoom

1993 NR NR

Women Men Rural

500 30 29

NR NR Nonsmoker

6.2 6.0 (2.1–9.7) 6.6 (4.0–9.0)

Phuapradit et al. (1994) Wananukul et al. (1998) Suwansaksri & Wiwanitkit (2001)

Abu Dhabi

1999

Men

100

NR

19.8; 13.3b

Bener et al. (2001)

NR, not reported; ND, not detectable a Unless specified otherwise b GM, geometric mean

No. of subjects

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Table 60 (contd)

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Table 61. Lead concentrations in blood in adults and children in Australia

Mencel & Thorp (1976) Moore et al. (1976) de Silva & Donnan (1977) de Silva & Donnan (1980) Calder et al. (1986) Wilson et al. (1986) Fett et al. (1992)

Sydney, NSW

1974

Adults

Tasmania

NR

Clerks and students

Melbourne, Vic.

NR

Male office workers

Victoria, Vic.

1979

Children

Adelaide, SA, industrial suburb Port Pirie, SA

1984

Threlfall et al. (1993) Gulson et al. (1994) Taylor et al. (1995) Mira et al. (1996) Chiaradia et al. (1997) Maynard et al. (2003)

Age (years)

Blood lead concentration (µg/dL)

AM (range)

NR

12.4

2.7–51.1

47

18–61

14.3

SE, 0.72

20

42.8

10.9

SD, 2.8

446

School age

11.4

3–3.7

Boys and girls

513

≤ 4 yrs

16.3

2.7% > 30 µg/dL

1982

Boys and girls

1239

1–14

18.2

Central Sydney, NSW, inner urban areas Perth, WA

1991–92

Boys and girls

158

9–48 months

11.2

15.4% ≥ 25 µg/dL 95.4% ≥ 10 µg/dL 50.6% > 10 µg/dL

1991

Boys and girls

123

0.2–17

6.9a

3.2–14.7

Broken Hill, NSW

1991–92

Adults and children

146

NR



2.7–47.1

Victoria, Vic.

1993

Children

252

0.3–14

5.4a

1.0–36.8

Central and southern Sydney, NSW Goulburn, NSW

1992–94

Boys and girls

718

9–62 months

7.0

16.1% > 10 µg/dL

NR

Port Pririe, SA (town with widespread contamination from lead smelter)

1993 1994 1995 1997 1998 1999

Children of employees Control children Boys and girls Boys and girls Boys and girls Boys and girls Boys and girls| Boys and girls

8 10 679 551 803 753 775 825

2–5 2–5.5 1–4

133

5.7 4.1 13.6 13.3 12.1 11.4 10.1 10.6

SD, 1.7 SD, 1.4 NR NR NR NR NR NR

Comments

Capillary blood samples Venous blood samples

Lead–zinc–copper mine employees Surveys evaluating interventions

133

AM, arithmetic mean; NR, not reported; SE, standard error; SD, standard deviation a Geometric mean

No. of subjects

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Reference

Reference

Comments

1980

555

1–9

59.2 ± 25.0 (16.0–152.1)

ZPP: 95.3 ± 80.2 µg/dL (3.8–782.8)

Carvalho et al. (1984, 1985a); Silvany-Neto et al. (1985); Tavares (1990)

Initial survey

Lead in hair: 558 ± 644 ppm

Carvalho et al. (1989)

ZPP: 70.4 ± 43.9 µg/dL (10.3–522.7)

Silvany-Neto et al. (1989); Tavares (1990, 1992)

90-m chimney built; population within 300 m from smelter transferred; EDTA treatment for 31 children; discontinued donation of smelter dross and used filters to neighbours; installation of stack filters; provided working clothes to employees

ZPP: 65.5 ± 1.7 µg/dLb

Silvany-Neto et al. (1996); Carvalho et al. (1996, 1997)

Higher values found in girls; children with darker-skinned racial background; smelter slag present in home; children with pica; children of smelter workers

Carvalho et al. (2003)

Smelter closed in 1993 Sources of exposure remaining; higher blood lead found in: children with pica; smelter slag present in home; malnutrition; lead intoxication family history; sewage tubing being placed with disturbance of slag previously used on streets

263 1985

250

1–9

1992

100

1–5

1998

47

1–4

a b

36.9 ± 22.9 (2.9–150.0)

17.1 ± 7.3 (2.0–36.2)

ZPP, zinc protoporphyrin; SD, standard deviation Geometric mean

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Table 62. Lead concentrations in blood in children living near the Santo Amaro smelter in Bahia, Brazil

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Table 63. Lead concentrations in blood in children in Latin America and the Carribean Source of exposure

No. of subjects

Age (years)

Mean blood lead (µg/dL)

Reference

Chile

Antofagasta

1997–98

Lead storage site (railway) Port area No exposure

432

0–7

8.7 ± 1.99a

Sepúlveda et al. (2000)

54 75

0–7 0–7

6.9 ± 1.94a 4.2 ± 1.54a

Equador

La Victoria Zamora Province

NR NR

Ceramic glazing No exposure

166 56

0.3–15 1–15

40.0 (6.2–119.1) 6.6 (2.0–18.0)

Counter et al. (2000)

Jamaica

NR

1994–95

Rural Urban Former mining area

242 90 61

3–11 3–11 3–11

9.2b (3–28.5) 14.0b (4–34.7) 35b (18–> 60)

Lalor et al. (2001)

Mexico

Mexico City

< 1992

Urban

782 girls 801 boys

5–11 5–11

10–17 14–16.7

Olaiz et al. (1996)

Ciudad Juárez, Chihuahua

1974

Smelter < 1 mile 1–2.5 miles 2.6–4 miles 4.1–6 miles 6.1–8 miles Total

1–9 35 113 198 200 206 752

Ordóñez et al. (2003) 38.7 31.6 28.7 28.5 27.7 29.3

NR, not recorded a Geometric mean b Median value

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135

City/area

Year(s) of study

Population

No. of subjects

Age (years)

Blood lead (µg/dL) AMa

Reference

Range

2000

B+G

779

4–12

12.3–17.5b

China

Jiangsu Shanghai Beijing Multiple sites

NR NR 1990 NR

B+G B+G B+G B+G

27 83 287 [3746]

6–9 8–13 5–7 1–15

8.8 18.4 7.8–12.3b 6.6–96.8

5.9–14.8 ND–55.0 3.9–24.8

Zhou & Chen (1988)c [Wang (1988)c] [Zheng et al. (1993)c] Shen et al. (1996)

Shanghai

1997 1998 1998–2001

B+G B+G B+G

1969 1972 959

1–6 1–6 5–12

9.6 8.1 49.6

0.1–69.7 1–23.9 19.5–89.3

Shen et al. (1999)

Rural area Shantou

NR 1999 2001

B+G B+G B+G B+G

207 469 332 457

5–9 mean, 8.5 1–5 1–5

12.6 50.5 10.4 7.9

4.6–24.8 22.0–93.8 3.4–38.6 1.1–29.5

Zheng et al. (2002) Luo et al. (2003)

China (Province of Taiwan)

Kaohsiung

1998–99

B+G

934

8–12

5.5

0.2–25.5

Wang et al. (2002a)

India

Delhi

NR

B+G

82

0.2–13

New Delhi Jammu 3 sites urban semi-urban rural Mumbai Mumbai Delhi

NR NR NR

B+G B+G B+G

75 50

3–5 3–5

9.6 23 11.6 30.8 14 15

25 75 50 566 560 190

5–15 5–15 5–15 6–10 6–10 4–6

32.0 25.0 15.0 8.6–14.4b 8.6–69.2b 7.8

NR [B+G] B+G

Wu et al. (2002)

Gogte et al. (1991)

4–40 4–87 25–43 20–31 13–22

Kaul (1999)

Capillary samples Capillary samples Capillary samples Review of 17 articles published between 1986 and 1994 After removal of lead from gasoline Children exposed to parental lead-recycling small industry Non-polluted area Rural area near smelter After removal of lead from gasoline in 1998

Control Pica Surma Pica + surma Finger-prick method

Kumar & Kesaree (1999)

Raghunath et al. (1999) Tripathi et al. (2001) Kalra et al. (2003)

Middle-class families Capillary samples Children with ZPP > 50 µg/dL

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1986–94 1984–96 1998

Kaiser et al. (2001)

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Table 64. Lead concentrations in blood in children in Asia

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Table 64 (contd) Country

City/area

Year(s) of study

Population

No. of subjects

Age (years)

Blood lead (µg/dL)

Jakarta

< 2001

B+G

397

6–12

8.6b

2.6–24.1

Albalak et al. (2003)

Capillary samples

Malaysia

Urban Semi-urban Rural

1997

B+G

179 112 55

7–11 7–11 7–11

5.3 2.8 2.5

0.9–18.5 0.1–12.3 0.05–5.2

Hashim et al. (2000)

Finger-prick method

Republic of Korea

Ulsan

1997 1999 2001

B+G B+G B+G

426 250 242

8–11 8–11 8–11

4.77b 5.11b 5.21b

Lee et al. (2002)

Lead in gasoline was reduced to 0.013 g/L in 1993.

Mongolia

6 sites

NR

NR

142

NR

0.34–1.75

Burmaa et al. (2002)

Highest in Ulaanbaatar

Pakistan

Karachi

NR NR 2000

Boys Girls B+G

77 61 400

6–8 6–8 3–5

16.9 15.12 12.0–21.6

Rahman et al. (2002)

6–12

8.1

mean, 3.4

27.8 30.6 30.3

5 districts in Karachi Saudi Arabia

Riyadh

NR

Girls

533

Thailand

Kanchanaburi, downstream lead refinery plant

1997 1998 1999

NR NR NR

48 48 48

Rahbar et al. (2002) 2.3–27.4

Al-Saleh et al. (2001) Tantanasrikul et al. (2002)

Initial survey After environmental deleading Second survey

NR, not reported; B, boys; G, girls; ZPP, zinc protoporphyrin a AM, arithmetic mean, unless stated otherwise b Geometric mean c Cited by Shen et al. (1996); references in square brackets could not be retrieved as original papers.

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Comments

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AMa

Reference

137

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(b)

Pregnant women and neonates

Lead concentrations were measured in maternal blood and umbilical cord blood from 50 parturient women at delivery in a hospital in Athens, Greece. Lead concentrations (mean ± standard deviation) for women living in industrial areas with high air pollution were 37.2 ± 4.7 µg/L in maternal blood and 20.0 ± 3.4 µg/L in umbilical cord blood (correlation coefficient, r = 0.57), while those for women living in agricultural areas with low air pollution were 20.5 ± 5.6 µg/L and 12.9 ± 3.6 µg/L, respectively (correlation coefficient, r = 0.70). The authors concluded that the placenta demonstrates a dynamic protective function that is amplified when maternal blood lead concentrations are increased (Dussias et al., 1997). Data from Kosovo (Serbia and Montenegro) showed that 86% of the pregnant women living in the vicinity of a lead smelter had blood lead concentrations ≥ 10 µg/dL, while in a comparable area not near a smelter, only 3.4% of pregnant women showed elevated concentrations (Graziano et al., 1990). Rabinowitz and Needleman (1982) reported an umbilical cord blood lead concentration of 6.6 µg/dL (arithmetic mean), with a range of 0–37 µg/dL, in over 11 000 samples collected between 1979 and 1981 in Boston, USA. A decrease in the blood lead concentration of approximately 14% per year was noted during the period of collection. Concentrations of lead (expressed as mean ± standard deviation) in umbilical cord blood of two groups of women giving birth in a hospital in Boston, USA, in 1980 and 1990, were found to be 6.56 ± 3.19 µg/dL and 1.19 ± 1.32 µg/dL, respectively (Hu et al., 1996a). In a study conducted at a medical centre in South Central Los Angeles, one of the most economically-depressed regions in California, USA, maternal blood lead concentrations in the third trimester of pregnancy were significantly higher in a group of 1392 immigrant women (geometric mean, 2.3 µg/dL) than in a group of 489 non-immigrant women (geometric mean, 1.9 µg/dL). Years living in the USA was the most powerful predictor of blood lead concentration. Drinking coffee during pregnancy, a history of pica, and/or low calcium intake were all significantly associated with higher blood lead concentrations (Rothenberg et al., 1999). In a study conducted in the United Arab Emirates, blood samples were collected from 113 mothers of 23 different nationalities and from their neonates (cord blood). Mean maternal blood lead concentration was 14.9 ± 2.14 µg/dL (range, 6.6–27.8 µg/dL) and mean cord blood lead concentration was 13.3 ± 2.49 µg/dL (range, 6.0–30.3 µg/dL). Sixteen per cent of samples from the mothers and 9% of cord blood samples had lead concentrations > 20 µg/dL (Al Khayat et al., 1997a). There are several studies showing high blood lead concentrations in pregnant women in India (Saxena et al., 1994; Awasthi et al., 1996; Raghunath et al., 2000). The mean blood lead concentration in a cohort of 500 pregnant women living in the slums of Lucknow, north India, was 14.3 µg/dL, and 19.2% of women had concentrations ≥ 20 µg/dL. Blood lead concentration was not associated with age, height, weight, gestation, or history of

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abortion, although it was higher with higher parity. Women living in inner-city neighbourhoods with heavy vehicular traffic had mean blood lead concentrations significantly higher than those living in other neighbourhoods (Awasthi et al., 1996). In another study conducted in Lucknow, India, the mean maternal blood lead concentration was significantly higher in cases of abnormal delivery (22.5 µg/dL) compared with normal deliveries (19.4 µg/dL). No significant difference in placental blood, cord blood and fetal membrane lead concentrations was observed between cases of normal and abnormal deliveries (Saxena et al., 1994). (c)

Children

Data on blood lead concentrations in children are presented in Tables 57–59 and 61–64. Between 1978 and 1988, decreases of 25–45% in average blood lead concentrations in children have been reported in Belgium, Canada, Germany, New Zealand, Sweden and the United Kingdom (OECD, 1993). Blood lead concentrations were measured in 286 children aged 0–7 years living in the three largest cities of Finland (n = 172), in rural areas (n = 54) and near a lead smelter (n = 60) (Taskinen et al., 1981). Mean blood lead concentrations among children in the urban, rural and lead-smelter areas varied between 6.0 and 6.7 µg/dL, with a range of 2–17 µg/dL. There were no statistically significant differences between groups. The five children who lived within 500 m of the lead smelter had a mean blood lead concentration of 9.2 µg/dL, with a range of 5–13 µg/dL, which was significantly higher than the mean blood lead concentration among 485 children in the rest of the country. In a study carried out in Sweden, 1395 blood samples were obtained from children living in an urban or rural area or near a smelter during the period 1978–88. The mean blood lead concentration for all locations together decreased from 6.4 µg/dL (range, 1.8–25 µg/dL) in 1978 to 4.2 µg/dL (range, 1.4–12.9 µg/dL) in 1984, to 3.3 µg/dL (range, 1.5–7.1 µg/dL) in 1988. The decrease was statistically significant for all three areas studied (Skerfving et al., 1986; Schütz et al., 1989). In Finland, the mean blood lead concentration for the children in two day-care centres in Helsinki was 4.8 µg/dL in 1983 (range, 2.1–8.3 µg/dL), 3.0 µg/dL in 1988 (range, 2.1–4.1 µg/dL), and 2.6 µg/dL in 1996 (range, 1.7–3.7 µg/dL) (Pönkä et al., 1993; Pönkä, 1998). In 1993, almost 30% of 431 children in a lead-mining community in the Upper Silesian industrial zone of Poland had blood lead concentrations > 10 µg/dL (Zejda et al., 1995). In Belovo, Russian Federation, lead releases from a metallurgy enterprise decreased between 1983 and 1996 from 120 to 9 tonnes per year, due to almost complete cessation of activity. In 1983, mean blood lead concentrations in newborn children and their mothers living in the area were 23.4 and 25 µg/dL, respectively; in 1996, mean blood lead concentrations in 91 children (age, 7–8 years) had decreased to 9.9 µg/dL (range, 0.5–39 µg/dL), with 46% of values still exceeding 10 µg/dL (Revich et al., 1998).

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In a community near a smelter in Bulgaria, blood lead concentrations in 109 children varied from 8–63 µg/dL. The higher concentrations in these children were correlated with the consumption of home-grown products. Lower blood lead concentrations were observed in children whose food came from a distant market (Fischer et al., 2003). The mean blood lead concentration in children in the USA has dropped dramatically since the late 1970s (Brody et al., 1994; Pirkle et al., 1994, 1998; CDC, 1997b, 2003a,b). Results of the NHANES studies in children aged 1–5 years are shown in Table 58. The NHANES II and NHANES III, Phase I, results showed that from 1976 to 1991, high blood lead concentrations correlated with low income, low educational attainment and residence in the north-eastern region of the USA (Pirkle et al., 1994). Data from Phase II of NHANES III (October 1991 to September 1994) indicated that blood lead concentrations in children aged 1–5 years continued to decrease and were more likely to be elevated among those who were poor, non-Hispanic black, living in large metropolitan areas or living in older housing (with potential exposure to lead from lead-based paint); approximately 4.4% of the children aged 1–5 years had blood lead concentrations ≥ 10 µg/dL (CDC, 1997b). In addition, 1.3% of children aged 1–5 years had blood lead concentrations ≥ 15 µg/dL and 0.4% had concentrations ≥ 20 µg/dL. The downward trends continued in 1999–2000 (CDC, 2003a). For all periods of this study, mean lead concentrations were consistently lower among the older age groups, i.e. age 1–5 years, 2.2 µg/dL; 6–11 years, 1.5 µg/dL; 12–19 years, 1.1 µg/dL in the period 1999–2000 (CDC, 2003a). A study assessing the source of lead exposure during early childhood in the USA showed that lead-contaminated floor dust was a major source of lead exposure during early childhood, whereas window sills became an increasingly important source as children stood upright (Lanphear et al., 2002). One of the most serious episodes of general population exposure to lead reported in Latin America occurred in Brazil (Table 62). For 24 years, a lead smelter processing 30 000 tonnes/year operated in the vicinity of Santo Amaro da Purificação (30 000 inhabitants) in the state of Bahia. No proper air pollution control system was used. Smelter dross (solid wastes) was distributed free of charge to the neighbouring population and spread over gardens, backyards, schools and streets, and chimney filters from the smelter were used in homes as carpets, bed spreads and rags. Four cross-sectional studies in children under 9 years of age were conducted in 1980 (Carvalho et al., 1985a), 1985 (Silvany-Neto et al., 1989), 1992 (Silvany-Neto et al., 1996) and 1998 (Carvalho et al., 2003). Blood lead concentrations were among the highest reported in the world. Most children involved in the last study were born after the smelter closed down in December 1993. Five years later, lead concentrations in blood averaged 17.1 ± 7.3 µg/dL, ranging from 2.0 to 36.2 µg/dL. Blood lead concentrations were approximately 5 µg/dL higher in children with pica, with visible presence of dross in home premises, with previous history of lead intoxication in the family and with malnutrition (Carvalho et al., 2003). In Antofagasta, Chile, a study was conducted with 432 children under 7 years of age living around a minerals storage site, 54 living near the port and 75 in non-exposed areas

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(Table 63). Average concentrations of lead in blood of exposed and unexposed children were 8.7 µg/dL and 4.2 µg/dL, respectively. Forty-seven per cent of exposed children, but no unexposed children, had blood lead concentrations > 10 µg/dL. The habit of pica, the number of cigarettes smoked daily at home, the level of education of the mother and having a mother working outside the home were variables that partly explained the variation in blood lead concentrations in the exposed area (Sepúlveda et al., 2000). In view of airborne lead pollution across the border from a lead smelter in El Paso, TX, USA, an epidemiological study on lead was conducted in 1974 in Juárez City, Chihuahua, Mexico, among 752 children aged 1–9 years. The average blood lead concentration was 29.27 ± 7.30 µg/dL in children living within 8 miles of the lead source. Concentrations decreased with greater distances from the smelter (Ordóñez et al., 2003; see Table 24 and Section 1.4.1(b)). Lead-glazing of ceramics has for many years been a source of exposure of the population of La Victoria, Ecuador, where around 70 kilns operate within an area of 250 km2. One hundred and sixty-six children aged 4 months to 15 years living in the area and many of them helping their parents in glazing activities had blood lead concentrations ranging from 6.2 to 119.1 µg/dL (mean, 40.0 µg/dL) compared with an average of 6.6 µg/dL in a reference population of 56 children aged 1–15 years living 500 km away in the province of Zamora. Lead isotope ratios of the soil and blood samples were highly similar and clustered for both study areas, indicating that lead in soil resulting from contamination by the glazing activities is probably one of the main routes of exposure to lead in these children (Counter et al., 2000). Blood lead concentrations among children in several Asian countries (Table 64) were basically similar to those in adults (Table 60), and were generally between 5 and 15 µg/dL (geometric mean). It should be noted, however, that finger-prick or capillary blood samples were employed in some studies (see Section 1.5 for quality assurance). Blood lead concentrations in children in Mongolia (Burmaa et al., 2002) were substantially lower than in all the other studies listed in Table 64. In a study carried out at 15 sites in India, the highest (69 µg/dL) and second highest (21 µg/dL) geometric mean blood lead concentrations were observed in children who lived near a scrap-yard and near a lead smelter, respectively. Values for children in the remaining sites were in a range of 9–14 µg/dL (Tripathi et al., 2001). Wu, Y. et al. (2002) observed significantly higher blood lead concentrations in children who lived in an area polluted by lead from a battery-recycling plant compared with a control group. Similarly, Zheng et al. (2002) described elevated blood lead concentrations (up to 94 µg/dL) in children living in an area with heavy lead pollution. Tantanasrikul et al. (2002) found high blood lead concentrations in children in a Thai village area downstream from a lead refinery plant. Wang et al. (1998) reported that 22 of 36 children in a kindergarten near a battery recycling factory in Taiwan, China, had blood lead concentrations in excess of 15 µg/dL in comparison with none of 35 children in a kindergarten in a non-exposed area. In a study of 566 children aged 6–10 years residing in 13 locations in Mumbai, India, a correlation coefficient of 0.88 was observed between air lead and blood lead concen-

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trations. It was also found that a 1-µg/m3 increase in lead concentration in air resulted in a 3.56-µg/dL increase in blood lead concentration in children (Raghunath et al., 1999). In another study among children in India, the differences in the mean blood lead concentrations were statistically significant (p < 0.001) between the urban, semi-urban and rural populations. The age-related differences in blood lead concentrations were also significant for urban, semi-urban and rural children (Kumar & Kesaree, 1999). In a study comparing children with and without pica in Delhi, India, only six out of 82 children with no symptoms of pica had a mean blood lead concentration ≥ 30 µg/dL (30–39 µg/dL). Among 88 children with pica, 26 had high blood lead concentrations (30–92 µg/dL) (Gogte et al., 1991). Among 400 children aged 36–60 months from the city centre, two suburbs, a rural community or an island situated in the harbour at Karachi, Pakistan, about 80% had blood lead concentrations > 10 µg/dL, with an overall mean of 15.6 µg/dL. Housing near a main intersection in the city centre, application of surma (a lead-containing cosmetic) to children’s eyes, father’s exposure to lead at the workplace, father’s illiteracy, child’s handto-mouth activity and eating from street vendors were among variables found likely to be associated with elevated lead concentrations in blood (Rahbar et al., 2002). The phase-out of leaded gasoline in Indonesia began in Jakarta on 1 July 2001. In a study conducted before the beginning of the phase-out activities, 35% of children aged 6–12 years in Jakarta had blood lead concentrations ≥ 10 µg/dL and 2.4% had concentrations ≥ 20 µg/dL. Lead concentrations in the blood of children who lived near a highway or major intersection were significantly higher than those in children who lived near a street with little or no traffic. The source of household water was also a significant predictor of blood lead concentrations ≥ 10 µg/dL, after adjustment for age and sex (Albalak et al., 2003). Hashim et al. (2000) measured blood lead concentrations in urban and rural primaryschool children in Malaysia; the percentage of children with blood lead ≥ 10 µg/dL was 6.36% overall, and was highest for Kuala Lumpur (11.73%). Urban schoolchildren were found to have higher blood lead concentrations than their rural and semi-urban counterparts, even after controlling for age, sex, parents’ education and income levels. 1.4.3

Occupational exposure

Potentially high levels of lead may occur in the following industries or workplaces: lead smelting and refining industries, battery manufacturing plants, steel welding or cutting operations, construction, painting and printing industries, firing ranges, vehicle radiator-repair shops and other industries requiring flame soldering of lead solder, and gasoline stations and garages. Workers in many occupations and job activities within or outside these industries have the potential for relatively high exposures to lead with varying degrees of frequency (Fu & Boffetta, 1995; ATSDR, 1999; NIOSH, 2001). These exposures and workers are (the asterisks indicate occupations for which there is at least one epidemiological study of lead

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143

exposure and cancer, as summarized in Section 2 of this volume): on-going exposure — battery-production workers*, battery-recycling workers*, foundry workers, lead chemical workers*, lead smelter and refinery workers*, leaded-glass workers*, pigment workers*, vehicle radiator-repair workers and traffic controllers; moderate frequency of exposure — firing-range instructors, house renovators, lead miners*, newspaper printers*, plastics workers*, rubber workers, jewellery workers, ceramics workers and steel welders and cutters; low frequency of exposure — automobile-repair workers, cable-production workers, construction workers, demolition workers, firing-range participants, flamesolder workers, plumbers and pipefitters, pottery-glaze producers, ship-repair workers and stained-glass producers. Epidemiological studies have also reported exposure to organic lead compounds, at a chemical plant in Texas, USA, and at an organic lead manufacturing company in New Jersey, USA. However, there are a number of activities that present a potential for high lead exposure but for which no epidemiological data are available. The most common route of occupational exposure to lead is through inhalation of lead fumes or lead dusts from ambient air, leading to absorption of lead through the respiratory system. Lead may also be ingested and absorbed in the gastrointestinal tract. Organic lead is absorbed through the skin (Bress & Bidanset, 1991). The lead concentration in air can be measured as a means of monitoring occupational exposure in work areas. However, occupational exposure is more often inferred from measurement of blood lead concentrations in individual workers. Workers occupationally exposed to lead may carry lead home on their body, clothing and tools. Thus, children of workers exposed to lead can also be at increased risk of exposure. For example, blood lead concentrations of children in households of occupationallyexposed workers were found to be almost twice those of children in neighbouring homes whose parents were not exposed to lead in their occupation (median ranges, 10–14 and 5–8 µg/dL, respectively) (Grandjean & Bach, 1986). Exposures to lead in workers’ families have been identified in association with nearly 30 different industries and occupations; the most commonly reported include lead smelting, battery manufacturing and recycling, radiator repair, electrical components manufacturing, pottery and ceramics and stained-glass making (NIOSH, 1995). The results of surveys of occupational exposure to lead in a large variety of industries in New Zealand, expressed as air lead concentrations and/or blood lead concentrations for the period 1988–89, are presented in Table 65 (Grant et al., 1992). Lead concentrations in workplace air and in the blood of exposed workers for specific job categories are presented in Tables 66–73. Whereas lead concentrations in air were reported only in a limited number of studies, blood lead concentrations are available for most studies and the exposure intensity is evaluated in terms of blood lead for the groups of exposed workers. Examples of extreme exposures reported in the literature include mean occupational air lead concentrations as high as 1200 µg/m3 for welding structural steel, 4470 µg/m3 for primary smelting and 5400 µg/m3 within a storage-battery plant (WHO, 1977).

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Table 65. Occupational exposure to lead in men in New Zealand, 1988–89 Occupation in order of decreasing mean blood lead concentration

Radiator repairer Smelter/furnaceman Muffler repairer Scrap metal worker Foundryman general Metal moulder Container repairer Engine reconditioner Panel beater Metal machinist Printer Gas cutter/welder Spray painter Plastic worker Metal polisher Paint removal worker Painter/decorator Leadlight worker Metal extruder Garage mechanic Miscellaneous lead product worker Pottery/ceramics worker Workers exposed to exhaust fumes Plumber Cable jointer Car assembler Electroplater Boat builder Bright solderer Petrol pump attendant

No. of workers

51 57 33 69 58 24 13 33 22 35 4 17 42 55 29 8 208 11 16 47 65 3 6 10 174 25 17 30 9 10

Blood lead (µg/dL) Mean

SD

Range

78.7 78.7 70.4 66.2 64.2 64.2 60.0 53.8 55.9 55.9 55.9 43.5 43.5 43.5 43.5 41.4 41.4 39.3 35.2 35.2 31.1 29.0 26.9 26.9 26.9 26.9 22.8 20.7 20.7 20.7

47.6 51.8 33.1 60.0 49.7 66.2 26.9 33.1 47.6 43.5 33.1 49.7 29.0 35.2 55.9 22.8 51.8 29.0 31.1 43.5 35.2 24.8 26.9 20.7 26.9 31.1 18.6 18.6 20.7 14.5

11–155 14–148 31–109 14–145 23–128 14–181 40–61 23–154 23–115 18–111 28–69 6–90 17–80 9–124 10–119 19–54 5–181 14–64 18–77 9–82 5–113 9–46 14–47 12–46 5–91 5–76 9–46 7–47 11–49 5–33

Adapted from Grant et al. (1992) SD, standard deviation

A NIOSH Health Hazard Evaluation (HHE) is a study of a workplace in the USA conducted to learn whether workers are exposed to hazardous materials or harmful conditions. The HHE is not necessarily representative of an industry or general work practices, since the inspections and measurements are typically done in response to a request by an employee, an officer of a labour union that represents employees, or any management official on behalf of the employer. Table 74 presents data from a series of HHE reports where blood and air concentrations of lead have been measured.

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Table 66. Lead concentrations in blood of occupationally exposed subjects: lead–acid battery factories Country or area

Battery repairb

Study population M

No. of subjects

15–66

Job history (years)

Smoking status

Blood lead (µg/dL)

Lead in air (µg/m3)

AMa

AMa

Range/SD

Reference

Range/SD

≤1 1–3 ≥4

NR NR NR

35.0c 37.3c 47.7c 36.7c 44.0c

NR

Carvalho et al. (1985b)

NR

Vaglenov et al. (2001)

15–18 19–66

Bulgaria

1992–96

Lead–acid battery

M

103

39.1

9.7

Included

56.2

China

1950–83

Lead–acid battery Charging Plate moulding Printing

NR NR NR

30 34 30

NR NR NR

NR NR NR

NR NR NR

26.2d 25.6 d 22.8 d

NR NR NR

500 60 5

Wang (1984)

NR

Lead–acid battery

M W

118 101

37.0 36.3

> 6 months > 6 months

80% 2%

67.0 45.0

± 26 ± 18.7

190

Lai et al. (1997)

NR

Lead–acid battery

M W

120 109

18–67 18–71

0.2–35 0.2–17

38% smokers

67.7 48.6

± 28.2 ± 17.0

≥ 0.1 in 46% of samples

Wang et al. (2002b)

1989–98

Lead–acid battery

17 M 13 W

30

38.3

13.1

NR

20–60d,e

NR

Hsiao et al. (2001)

1991 1997

Lead–acid battery

M+W M+W

284 392

NR NR

NR NR

Included Included

34.7 23.9

NR NR

Chuang et al. (1999)

Finland

NR

Lead–acid battery

M+W

91

40.6

12.2

NR

30

NR

Erkkilä et al. (1992)

Irak

1996

Lead–acid battery Charging Repair Casting

M M M

11 8 18

NR NR NR

>4 >4 >4

40% smokers

36.4 58.0 71.7

China (Province of Taiwan)

± 15.0 ± 12.4

± 11.40 ± 13.35 ± 24.80

NR NR NR

Mehdi et al. (2000)

Page 145

5 11 23 6 33

Age (years)

11:26

[1984]

Job/task

INORGANIC AND ORGANIC LEAD COMPOUNDS

Brazil

Year(s) of survey

145

Israel

Year(s) of survey

1975

Job/task

Study population

No. of subjects

Age (years)

Job history (years)

Smoking status

Blood lead (µg/dL) AM

41.3 41.3 47.0 35.2 43.9

13.3 5.5 9.8 4.3 13.1

NR

15

31.9

NR NR

3 4

36.3 33.5

Most smokers

Range/SD

28.6 44.0 55.0 59.5 58.4

20–34 43–46 41–73 43–87 43–73

14.5 23 49.3 84.5 190

11.9–17.0 – 48–50.7 71–98 118–299

4.6

75.2

48–105

399

266–475

6.5 6.4

76.3 90.7

64–90 79–108

885 1187

Richter et al. (1979)

– 1060–1315

Japan

NR

Lead battery, mostly

M W

214 44

NR NR

≥2 ≥2

NR NR

48.9c 49.1c

17.0–101.0 28.0–75.0

NR NR

Fukui et al. (1999)

Philippines

1990

Lead–acid battery

M

199

33.8

10.7

NR

64.5b

23–121

NR

Makino et al. (1994)

Republic of Korea

NR

Lead–acid battery Casting and pasting Plate forming, finishing Assembling Others

NR

66 5

40 39

≥ 3 months

NR

45.7 40.6

± 15.7 ± 8.8

NR 83

40–154

17

44

49.2

± 17.4

170

12–468

22 22

39 39

47.2 42.6

± 11.6 ± 18.7

145 NR

15–411

Lead–acid battery Cast-on-strap Plate processing Battery cell setting Finish processing Supervisor

14 M, 78 W

92 37 3 19

40.1

Lead–acid battery

M W

NR

1998

8.6

NR

21 12 156 56

36.3 47.0

8.8 6.2

68% smokers Nonsmokers

27.6 29.6 36.8 22.6

19c 32c 29c 13c

22.4 44.5

9c 27c

32.0 19.8

± 13.0 ± 9.2

NR NR

Kim et al. (1995a)

Hwang et al. (2000)

Hwang et al. (2001)

Page 146

3 3 6 17 10

AM

Reference

11:26

NR NR NR NR NR

Range/SD

a

IARC MONOGRAPHS VOLUME 87

Administration Maintenance Assembly Miscellaneous Grid smelting and casting Plate drying and formation Oven smelting Pasting/drying/ oxide formation

a

Lead in air (µg/m3)

09/08/2006

Country or area

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Table 66 (contd)

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Table 66 (contd)

Lead–acid battery

Study population

No. of subjects

Age (years)

Job history (years)

Smoking status

Blood lead (µg/dL)

Lead in air (µg/m3)

AMa

Range/SD

AMa

Range/SD

M Chinese Malay

11 25

39.1 31.7

10.8 7.5

Included Included

23.6 34.3

12.4 10.5

35 51

± 31 ± 39 ± 176.3

NR

Lead–acid battery

M

50

38.3

10

NR

32.5

19.1–50.9

88.6

1987–89

Lead–acid battery

NR

61

NR

NR

NR

28.4

12.9

NR

South Africa

NR

Lead–acid battery

M

382

41.2

11.6

52% smokers

53.5

23–110

Turkey

NR

Lead–acid battery

M

71

32.7

NR

73% smokers

34.5

13.4–71.8

USA

1947–72

Lead–acid battery

M

1083

NR

>1

NR

62.7

NR, not reported; M, men; W, women a Arithmetic mean, unless stated otherwise b Nineteen different establishments recycling batteries; 76.9% of the workers operating in areas < 30 m2 and involved in fusion of lead c Geometric mean d Median value e Values read from graph

145

Reference

Chia et al. (1991) Ho et al. (1998) Chia et al. (1993)

10–5480

Ehrlich et al. (1998)

NR

Süzen et al. (2003)

NR

Wong & Harris (2000)

Page 147

NR

Job/task

11:26

Singapore

Year(s) of survey

INORGANIC AND ORGANIC LEAD COMPOUNDS

Country or area

147

Year of survey

Job/task

Study population

M+W

Italy

1977–78

Primary smelter

M

Japan

NR

Copper smelter Blending Smelting Converter Anode

M

AMa

Range/ SD

AMa

NR

22–25

NR

NR

NR

NR

Included – – – – Current Former Never

8.9 13.5 15.7 25.7 26.3 21.0 25.9

± 5.5 ± 7.2 ± 7.3 ± 6.1 14–39 19–23 15–34

7 29 41 313

Smoking status

368

NR

NR

1388

NR

>1

13 51 28 31

42.9 (21–60)

47.6

Reference

Range

Fleming et al. (1998) 1–1650

5–8 6–67 17–78 165–436

Cocco et al. (1997) Karita et al. (2000)

Kazakhstan

1998

Smelter and mining

NR

38

NR

NR

NR

34

13–> 65

NR

Kaul et al. (2000)

Sweden

1987

Primary smelter

Active Retired

70 30

37.4 67.9

14.3 32.6

NR NR

32b 9.9b

5.0–47.4 3.3–20.9

NR

Gerhardsson et al. (1993)

Sweden

1950–87

Primary smelter Other metal workers Other personnel

M

3979

NR

NR

NR

62.1–33.1c 55.9–16.6c 53.8–12.4c

NR

Lundström et al. (1997)

United Kingdom

1970–79

Cadmium plant Furnace area Sinter area

M M M

123 426 343

NR NR NR

>1 >1 >1

NR NR NR

28 59 56

50% > 2000 in whole plant

Ades & Kazantzis (1988)

USA

1976

Primary smelter

M

173

NR

9.9

NR

56.3

3100

Steenland et al. (1992)

NR, not reported; M, men; W, women a Arithmetic mean, unless stated otherwise b Median value c Decrease over the study period

Page 148

Primary smelter

Lead in air (µg/m3)

Years of employment

11:26

1994

Blood lead (µg/dL)

Age years mean (range)

IARC MONOGRAPHS VOLUME 87

Canada

No. of subjects

09/08/2006

Country

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Table 67. Lead concentrations in blood of occupationally exposed subjects: mining/primary smelter

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Table 68. Lead concentrations in blood of occupationally exposed subjects: secondary smelter Country or area

Year(s) of survey

Age years mean (range)

Job history (years)

Smoking status

Range/ SD

Lead in air (µg/m3) AMa

14 16 4

NR NR NR

60–270

NR

Ankrah et al. (1996)

Blood lead (µg/dL) AMa

Reference

Battery recycling Furnace Fragmentation Office, guards

NR NR NR

19 10 5

37 35 52

11 months 15 months 31 months

NR NR NR

87 69 38

Wang et al. (1998)

NR

Battery recycling

23 M, 2 W

25

(18–60)

≥5

NR

108

Japan

NR

Secondary lead smelter

19 M, 3 W

22

47 (22–63)

5

NR

43

8–78

NR

Tomokuni et al. (1992)

Philippines

NR

Secondary lead smelter (battery recycling)

M W

107 6

32.1 27.8

6.6 4.0

NR NR

80.8b 44.7b

19–153 35–61

NR NR

Makino et al. (1994)

Republic of Korea

1996

Secondary lead smelter A B C D E

83 M, 5 W M+W M+W M+W M+W M+W

88 12 17 18 25 16

NR

> 1 month

NR

52.4 47.4 47.2 49.7 55.4 60.0

17.7 18.8 20.7 13.1 19.7 12.1

324 310 194 464 316 290

Kim et al. (2002)

Sweden

1969–85

Secondary smelter

M

664

28 at entry

2.8b

NR

62.1–33.1c

NR

Gerhardsson et al. (1995a)

USA

1947–72

Smelters (primary, second, recycling)

M

254

NR

>1

NR

79.7

NR

Wong & Harris (2000)

NR, not reported; M, men; W, women; A–E, five different lead smelters Arithmetic mean, unlewss stated otherwise b Median value c Decrease over the study period

a

Page 149

Ghana

No. of subjects

11:26

NR

Study population

INORGANIC AND ORGANIC LEAD COMPOUNDS

China (Province of Taiwan)

Job/task

149

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09/08/2006

Job/task

Study population

No. of subjects

Age (years)

Job history (years)

Smoking status

China

NR

Lead-coloured glass

Women

36

21–35

2–17

Never

Japan

1989–90

Lead-coloured glass high exposure low exposure

NR

5 (15)b (60)b

29–55

2–17

NR

Lead glass processing and lead pigment production

Men Women

160 138

36 28

NR

NR, not reported a Arithmetic mean Number of samples collected during 15 months

b

1–28 1–28

NR NR

Blood lead (µg/dL)

Lead in air (mg/m3)

AMa

Range

AMa

Range

55.6

25.8–79.3

NR

0.4–1.2

67.1 52.3

38–102 38–69

1050 286

741–1658 22–1331

55.1 54.7

18.1–87.9 21.5–99.4

NR NR

Reference

Murata et al. (1995) Hirata et al. (1995) Oishi et al. (1996a)

Page 150

Years of survey

IARC MONOGRAPHS VOLUME 87

Country or area

11:26

Table 69. Lead concentrations in blood of occupationally exposed subjects: leaded glass

Cor 151.qxd 01/09/2006

Table 70. Lead concentrations in blood of occupationally exposed subjects: welders and solders Year of survey

Job/task

Study population

No. of subjects

Age (years)

Job history (years)

Smoking status

Blood lead (μg/dL)

Lead in air μg/m3)

AMa

AMa

Range/SD

Radiator welding

M

22

27.7

1–40

NR

32.8b

NR

Shipyard welding

M

51

> 18

1–17

Includedc

12

4–31

NR

Mexico

NR

Radiator repair

NR

73 29 30

33.2

NR

Included Smoker Nonsmoker

35.5 40.4 32.3

6.7–79.4 13.9–79.4 14.6–56.9

19.1

Philippines

1999

Radiator mechanic

M+W

16

40.2

16.2

NR

20.0

NR

Welding mechanic

M

29

NR

NR

Nonsmoker

Thailand

NR

Mechanic

NR

40

NR

NR

USA

1992

Radiator repair

M

63

39

NR

Radiator repair

NR

56

39.5

1990

Radiator repair

NR

7

NR

1986

Radiator repair

NR

53

Soldering Philippines

NR

Electronic industry

M W

Singapore

1987

Electronics industry

NR

NR

Hunaiti et al. (1995) Mokhtar et al. (2002) 0–99

Dykeman et al. (2002)

± 10.6

NR

Suplido & Ong (2000)

9.1

5.0–17.0

NR

Suwansaksri et al. (2002)

Never

11.2

3.9–17.0

0.1–0.5

Suwansaksri & Wiwanitkit (2001)

11

39% current

29d

6.6–94

NR

Dalton et al. (1997)

NR

52% current

37.1

16–73

NR

NR

NR

NR

17–35

PBZ: 209

< 20–810 TWA: < 10–> 40

Tharr (1993)

37.1

14.3

60% current

31.7

5–58

Area: 40 PBZ: 113

0–281 0–590

Lussenhop et al. (1989)

21 193

25.4 21.9

1.8 1.8

NR NR

14.9b 9.9b

7–45 3–47

NR NR

118

NR

NR

16.1

± 8.5

110

NR

Goldman et al. (1987)

Makino et al. (1994) 10–1240

Chia et al. (1993)

NR, not reported; M, men; W, women; PBZ, personal breathing zone; TWA, time-weighted average Arithmetic mean, unless specified otherwise b Geometric mean c Stratification by smoking did not reveal a significant difference between values. d Median value

a

Page 151

NR

Malaysia

Range

INORGANIC AND ORGANIC LEAD COMPOUNDS

Welding Jordan

Reference

18:14

Country or area

151

09/08/2006

Country or area

Year(s) of survey

Job/task

No. of subjects

Age (years)

NR

NR

75% smokers

20–60

Max., 40

Blood lead (µg/dL) AM

a

Lead in air (µg/m3) a

Reference

Range/ SD

AM

Range

10.8b

± 1.26

NR

Zhou et al. (2001)

NR

68.3

37–97

NR

Ahmed et al. (1987)

China

1998

Taxi and bus drivers

M

164

Egypt (Alexandria)

NR

Traffic controllers

M

45

Egypt

NR

Traffic policemen

M

126

48.7

9–36

NR

29.2

7.5

NR

Kamal et al. (1991)

India

NR

Traffic constables Bus drivers

M M

88 22

41.7 43.6

2.7 5.6

30% 77%

11.2 12.1

0.5–40.2 0.5–35.7

NR NR

Potula & Hu (1996a,b)

Indonesia

1983

Policemen Drivers

M NR

24 22

NR NR

NR NR

NR NR

31 25

± 18 ± 17

NR NR

Jordan

NR

Bus drivers, gasoline station workers

NR

47

NR

NR

NR

Pakistan

1994–95

Traffic exposed Traffic police Transportation staff Shopkeepers

M

212 36 150 36

19–59

>1

Included

NR, not reported; M, men a Arithmetic mean, unless stated otherwise b Geometric mean

0.7–6.0 0.7–6.0

Suzuki (1990)

7.6

NR

Hunaiti et al. (1995)

52.2 53.4 51.1 52.1

NR

Khan et al. (1995)

Page 152

Smoking status

IARC MONOGRAPHS VOLUME 87

Job history (years)

11:26

Study population

P 141-164 DEF.qxp

152

Table 71. Lead concentrations in blood of occupationally exposed subjects: professional drivers and traffic policemen

P 141-164 DEF.qxp 09/08/2006

Table 72. Air and blood lead concentrations measured at indoor and outdoor firing ranges Country

Year(s) of study

Settings/task

No. of subjects and sex

Age (years)

Job history (years)

Lead in air (µg/m3)

AMa

Range

AMa

Range

22.4–59.6

GA, 134; PBZ, 413

NR

Reference

Employees in indoor range

10

NR

4–21

37.2

New Zealand

1990–91

Indoor small-bore rifle range

52 M + W

17–68

Recreational shooters

End of season, 55.0; start of season, 33.3

Sweden

NR

Indoor range Powder gun Air gun

22 M + W 21 M + W

42.4 46.8

10.2 13.7

13.8b 8.4b

6.9–22.8 2.0–22.2

660 4.6

1994

On- and off-duty police officers

75 M 3W

43 32

NR > 9 years

5.0 3.7

1.0–18.2

NR

Löfstedt et al. (1999)

NR

Indoor range for police officers

7

NR

NR

30–59

30–160

Smith (1976)

NR

Soldiers

35

21.9

4.2

19.25

TWA: 190

Brown (1983)

1985

Indoor range Full-time employee Part-time employee

NR

NR

2 2

Showroom, 2.7 Firing line, 13.6 Midway to target, 57.4; Target, 90.5

Novotny et al. (1987)

Covered outdoor range

15

United Kingdom

USA

1987

59–77 17–49

NR

NR

5.6 (preexposure) 10.7 (day 2) 14.9 (day 5) 8.7 (day 69)

PBZ, 120 GA, 140–210

9.6–30.1

GA, 68.4 PBZ, 128.5

Chau et al. (1995) George et al. (1993)

112–2238 1.8–7.2

3.8–298.6 34.7–314.3

Svensson et al. (1992)

Tripathi et al. (1989)

Page 153

NR

INORGANIC AND ORGANIC LEAD COMPOUNDS

China (Province of Taiwan)

11:26

Blood lead (µg/dL)

153

USA (contd)

Year(s) of study

Indoor range with training 3 Feb.–28 April

No. of subjects and sex

Age (years)

17 M + W

24–40

Job history (years)

Lead in air (µg/m3)

AMa

Range

AMa

Range

6.45 51.4 44.6 39.8

< 5–23.1 31.2–73.3 27.1–62.3 23.1–51.2

1483–1860 2906–3226 1231

304–2688 994–5589 553–2567c

Trainees

Covered outdoor range using copper-jacketed bullets

1987–88 June 1987 July 1987 Dec. 1987 April 1988 June 1988

Uncovered outdoor range

1987

Covered outdoor range Non-jacketed bullets Jacketed bullets

1991–93

1410 78.3 43.1 6

NR

NR

NR

NR

7 7 5

University rifle range Old ventilation system New ventilation system

Valway et al. (1989)

NR

GA, 9.53 PBZ, 5.88

28–66 – 25–70 – 28–38

– 460–510 (3-h TWA) – 100–170 (3-h TWA) –

5.50–14.56 0.42–7.66

Recreational shooters

GA, general area; NR, not reported; PBZ, personal breathing zone; TWA, time-weighted average a Arithmetic mean, unless stated otherwise b Median value c New ventilation system installed d Range of means of three sampling dates

Tripathi et al. (1990)

Goldberg et al. (1991)

Instructors

2 2 College students

Before shooting, 6.0 ± 1.7 After shooting, 6.5 ± 1.5

14.2–24.2d

10–27 13.1–22.1

67.1–211.1

36.7–431.5 5.4–8.7

Tripathi et al. (1991)

11.8–16.4 13.2–13.6

5–21 8–23

176 129

24–239 67–211

Prince & Horstman (1993)

Page 154

Lead bullet Nylon-coated Copper jacketed 1987

Reference

11:26

Blood lead (µg/dL)

IARC MONOGRAPHS VOLUME 87

1987 Jan.-Feb. March (early) March (late) May

Settings/task

09/08/2006

Country

P 141-164 DEF.qxp

154

Table 72 (contd)

P 141-164 DEF.qxp

Table 73. Lead concentrations in blood of occupationally exposed subjects: miscellaneous Year(s) of survey

Job/task

Sex

No. of subjects

Age (years) mean and/or range

Years of employment

Smoking status

AMa

Range/SD

AMa

Range

0.2–9.2

Reference

Mechanics/garage 1976

Automobile mechanics

M

138

16–68

NR

NR

40.0–44.8

50–125

3.19

Ghana

NR NR

Automobile mechanics Gasoline retailers

M M+W

25 40

17–46 20–46

2–29 0.1–17

NR NR

27.8 8.6

0–60 0–20

NR NR

Ankrah et al. (1996) Ankrah et al. (1996)

India

NR

Automobile mechanics

M

22

20–45

NR

NR

NR

24.3–62.4

NR

NR

Workers in petrol storage bunkers

NR

22

10–15

>1

NR

39.3

± 3.7

NR

Kumar & Krishnaswamy (1995b) National Institute of Nutrition (1995–96)

Jordan

NR

Mechanics

M

62

NR

NR

NR

8.1b

Thailand

NR

Repair mechanics

M

23

NR

NR

Nonsmokers

8.4

United Arab Emirates

1999

Heavy industry, garage and painting

M

100

34.8

8.3

NR

77.5

1973–82

Lead-exposed industry workers

M

18 329

33.8 at entry 37.5 at entry

0–46

NR

29.0–14.5b,c

0–46

NR

20.7–6.2

Others Finland

India

W

2412

3.9–14.5

Clausen & Rastogi (1977)

NR

Hunaiti et al. (1995)

NR

Suwansaksri et al. (2002)

NR

Bener et al. (2001)

NR

Anttila et al. (1995)

b,c

NR 1981 NR NR

Silver jewellery makers Papier-mâché workers Silver jewellery workers Printing press

M M+W M M

9 30 7 23

25–65 10–70 25–70 20–50

5–40 NR 12–50 15–30

NR NR NR NR

120.8 69.1 113.4 41.9

40.0–210.0 23–122 71.0–208.1 ± 7.0

NR NR NR NR

NR

Papier-mâché workers

M

70

17–40

3–26

NR

68.1

18.2–272.7

NR

Behari et al. (1983) Kaul & Kaul (1986) Kachru et al. (1989) Kumar & Krishnaswamy (1995a) Wahid et al. (1997)

India

NR

Printing press

M+W

25

18–35

3–5 6–9 9–15

NR

88 59 36

± 30 ± 22 ± 11

NR

Agarwal et al. (2002)

Italy

NR

Electrician

M

1

20

6

NR

66

NR

Franco et al. (1994)

Page 155

Denmark

11:26

Lead in air (µg/m3)

INORGANIC AND ORGANIC LEAD COMPOUNDS

Blood lead (µg/dL)

09/08/2006

Country

155

Japan

Year(s) of survey

Job/task

NR

Pigment (lead stearate) production Crystal toy production

NR

58 70 49

W

123

Cloisonné production Glazing Silver-plating

NR

Lead in air (µg/m3)

AMa

Range/SD

AMa

Refrain for 12 h NR

16.5b 11.1b 18.0

3.5–69.5 2.1–31.5 7–36

NR NR NR

NR

55.4

22.5–99.4

920

47.8 11.3

11.3–111 3.2–19.5

Years of employment

Smoking status

54.7 52.2 48.0 (27–63) 27.3 (17–44) NR

1–53 3–47 14.5 (2–34) 7.2 (0.8–25) NR

NR

49 16

Jordan

NR

Metal casting Car painting

M M

Malaysia

NR

Shipyard Painting Fabrication

M

26 85

NR NR

NR NR

NR NR

> 18

< 1–17

Included

15 19

41.6b 10.7b 16 12

8–38 3–28

Reference

Range

Ishida et al. (1996) Yokoyama et al. (1997) 390–1910

Nomiyama et al. (2002)

NR

Arai et al. (1994)

NR NR

Hunaiti et al. (1995)

NR

Mokhtar et al. (2002)

Nigeria (SW)

NR

Lead-exposed industry workers

NR

86

24.8

NR

Included

56.3

26–97 40% > 60

NR

Adeniyi & Anetor (1999)

Pakistan

1994–95

Tannery

M

46

19–59

>1

Included

60.6

± 3.8

NR

Khan et al. (1995)

Philippines

NR

Refrigerator production

M W

59 6

25.7 21.8

4.7 2.1

NR NR

21.5b 17.5b

8–38 14–22

NR NR

Makino et al. (1994)

Republic of Korea

1999

Various (24 facilities)

M+W

723

39.4

6.3

31.7

5.4–85.7

NR

Todd et al. (2001a)d

1997–99

Various (26 facilities)

639 M, 164 W

803

40.4

8.2

61% of smokers 57% of smokers

32.0

± 15

NR

Schwartz et al. (2001)d

1989

Plastics Metal products Solder production Paint production Telecommunication Ship building PVC compounding

NR NR NR NR NR NR M

104 70 22 88 218 92 61

NR NR NR NR NR NR 38.3

NR NR NR NR NR NR ca. 10

NR NR NR NR NR NR NR

26.0 32.5 25.0 14.3 15.4 17.9 23.9

± 15.8 ± 13.1 ± 9.1 ± 6.8 ± 5.7 ± 6.7 6.7–75.8

NR NR NR NR NR NR 35.7

Chia et al. (1993)

Singapore

NR

ND–277

Ho et al. (1998)

Page 156

NR

M W M

Blood lead (µg/dL)

Age (years) mean and/or range

11:26

Ceramic painting

No. of subjects

IARC MONOGRAPHS VOLUME 87

NR

Sex

09/08/2006

Country

P 141-164 DEF.qxp

156

Table 73 (contd)

P 141-164 DEF.qxp 09/08/2006

Job/task

Sex

No. of subjects

Age (years) mean and/or range

Years of employment

Smoking status

Blood lead (µg/dL)

Lead in air (µg/m3)

AMa

Range/SD

AMa

Reference

Range

United Kingdom

NR

Painters and decorators

M

3

22–51

NR

NR

[85.5]

84.2–87.1

NR

Uruguay

[1993]

Lead–acid battery and lead scrap smeltere

M

31

NR

9.5

12

49.7

24.4–87.0

NR

3–1300

Pereira et al. (1996)

USA

1984 1994 1994–96

Electronics industry Custodial activities Labourers Painters

M+W NR M M

151 13 60 83

> 11 40 38 39

NR 8.5 15.5 16.4

NR NR NR NR

8.0 5.4 11.2 7.0

1–22 2.8–10 1.2–50 1.5–26.3

NR 0.1–3.9 NR NR

61–7000 ND–36

Kaye et al. (1987) Tharr (1997) Reynolds et al. (1999)

NR, not reported; M, men; W, women; ND, not detectable a Arithmetic mean, unless stated otherwise b Geometric mean c Decrease over the 10-year study period d [The participants in the study by Todd et al. (2001a) most likely are included in the study by Schwartz et al. (2001).] e Two storage battery plants (n = 16, n = 8); lead scrap smelter (n = 6); one self–employed storage battery reconditioner

Gordon et al. (2002)

Page 157

Year(s) of survey

11:26

Country

INORGANIC AND ORGANIC LEAD COMPOUNDS

Table 73 (contd)

157

Year(s) of study

No. of workers tested

1990–91

Heavy abrasive blasting Moderate abrasive blasting

No. of samples taken

Type of sampling

AMa

Range

Landrigan et al. (1980) 13 19

33 61

25–47 30–96

4 3

PBZ PBZ

305 391

10–1090 24–1017 Sussell et al. (1992a)

8 6 16 Spring 1991 Summer 1991

23 12

Bridge, tunnel and elevated highway construction: renovation Blaster/painter Apprentice Recycling equipment operator

1993

22

Commercial testing laboratories Lakewood, CO Sparks, NV

1986

Copper foundries

1991

10

21

10–39

Electric services

1991

43

20

< 5–43

Electric services

1995

NR

NR

Electronic components

1993

NR

NR

Electronic components

1993

7

19

9–27

Fabricated metal products

1987

3

31

25–43

Fabricated plate work

1991

9

32

10–51

PBZ PBZ PBZ GA

[13 671] [78]

3620–29 400 9–194 5–6720b ND–8170

5–61 13–43 7.2

10

2.2–16.5

Ewers et al. (1995) 24 11 2

PBZ PBZ PBZ

250 110 140

3–1800 1–680 100–180

8 14

PBZ + GA PBZ + GA

321 114

90–800 4–490

7

PBZ

NA

ND–172

Clark et al. (1992)

18

PBZ

[9.4]

1.2–55

Venable et al. (1993)

43

PBZ

NA

ND–181

Mattorano (1996)

3

PBZ

NA

ND–36

Blade & Bresler (1994)

> 17–192

Gunter et al. (1986)

NR 4

PBZ

[803] NR

Guo et al. (1994) 7.3–1900

Lee (1987) Hales et al. (1991)

Page 158

Bridge, tunnel and elevated highway construction: repainting Inside containment Inside containment, inside hood Outside containment

Range

11:26

1980

AMa

Reference

IARC MONOGRAPHS VOLUME 87

Bridge, tunnel and elevated highway construction: deleading Grit blasting Scraping and priming

Air lead (µg/m3)

Blood lead (µg/dL)

09/08/2006

Industry

P 141-164 DEF.qxp

158

Table 74. NIOSH Health Hazard Evaluation reports with air and/or blood lead concentration data, 1978–2003

P 141-164 DEF.qxp

Table 74 (contd) Year(s) of study

Air lead (µg/m3)

Blood lead (µg/dL) Range

17

34

11–77

1991

General contractors, industrial buildings and warehouses Oxyacetylene cutting Other renovation tasks

1989

General contractors, single family houses: lead paint abatement

1989–91

95

General contractors, single family houses

1993

53

5.2c

General contractors, single family houses Manual paint scraping Power paint removal

1998

NR

NR

General contractors, single family houses

1996–98

40

16

General contractors, single family houses

1999

NR

General contractors, single family houses

1999

Glass products, stained glass art studio

16

[10]

Type of sampling

AMa

Range

3 3 4

PBZ PBZ-LT PBZ-LT

[254] [354] [32]

215–307 282–390 0–46

3–21

McCammon et al. (1991)

Stephenson & Burt (1992) PBZ PBZ

522 NA

160–1300 ND–2

1402 1233

PBZ GA

3.1c 2.0c

< 0.4–916 < 0.4–1296

Sussell et al. (1992b)

PBZ GA Task-based PBZ

3.2c 0.6c 0.2–9.1c

0.05–12 0.1–25 0.03–120

Sussell et al. (1997)

PBZ-ST PBZ-ST

NA [5054]

< 1–250 54–27 000

20 152

PBZ Task-based PBZ

29c 1.3–150

1.5–1100 0.17–2000

Sussell et al. (2000)

NR

128 130

PBZ GA

22c 1.5c

ND–660 ND–37

Sussell & Piacitelli (2001)

NR

NR

15 5 79

PBZ GA Task-based PBZ

100c [2.2] 71c

39–526 0.29–6.1 1.4–2240

Sussell et al. (2002)

1986

3

[19]

7–33

7

PBZ + GA

80

10–260

Gunter & Thoburn (1986a)

Glass products, made from purchased glass

1991

18

12

< 10–24

4

PBZ

18

7–35

Lee (1991)

Glass products, made from purchased glass

1993

2

2

1.8–2.1

17 13

PBZ GA

NA NA

ND–80 ND–0.7

Donovan (1994)

Gold ores (fire assay)

1987

NR

NR

4 5

PBZ GA

76 48

36–117 14–100

Daniels (1988)

ND–27 NR–17.5

13 37 77 5 6

1–65

Sussell & Piacitelli (1999)

159

6 9

Page 159

Fabricated plate work Lead burners Tinning Grinding

No. of samples taken

11:26

AMa

Reference

INORGANIC AND ORGANIC LEAD COMPOUNDS

No. of workers tested

09/08/2006

Industry

Industry

1989 6 5

42 18

23–65 7–36

Gold ores (fire assay)

1989

6

42

23–65

AMa

1 6

PBZ GA

850d NA

ND–110

1 4

PBZ GA

170 NA

ND–170

3 5

PBZ GA

[112] [26]

15–200 6–61

Lee et al. (1990a)

10d 10–30d

Hales & Gunter (1990)

ND–70 30–70

Gunter (1985)

Gold ores (fire assay)

1989

6

37

Gold ores, assay laboratory

1989

2

< 40

1 3

PBZ GA

Grey iron foundries

1985

NR

NR

4 3

PBZ GA

NA 53

Heavy construction Before blasting During blasting, outside containment During blasting, inside containment, inside helmet

1991

6

Industrial inorganic chemicals

1980–81

Industrial valves

Range

Daniels & Hales (1989) Daniels et al. (1989)

Sussell et al. (1992c) 34 before job 28 during job

15–44 6–43

6 5 4

PBZ PBZ GA PBZ

ND–35 ND–47 620–3000

79

35

NR–69

75

PBZ

13–79

0–359

Landrigan et al. (1982)

1989

25

15

< 20–33

2 4

PBZ GA

[91] [69.5]

87–94 32–120

Kinnes & Hammel (1990)

Inorganic pigments Bagging zinc oxide Mixing zinc oxide Mixing barium ores Mixing of inert clays

1981

228

[33] [34] [9] [2]

9–96 16–68 ND–15 ND–8

Motor vehicle parts and accessories

1981

66

23

25

PBZ

37

7–113

Zey & Cone (1982)

Motor vehicle parts and accessories

1983

14

31 ± 12

7

PBZ

[49]

25–104

Ruhe & Thoburn (1984)

Motor vehicle parts and accessories

1986

5

< 29–60

4 4

PBZ GA

[172] [68]

40–380 20–190

Gunter & Thoburn (1986b)

16–25

8–32 11 5 7 4 11–52

Slovin & Albrecht (1982)

Page 160

13–55

Type of sampling

No. of samples taken

11:26

Range

Reference

IARC MONOGRAPHS VOLUME 87

AMa

No. of workers tested Gold ores (fire assay) Assay laboratory personnel Non-assay laboratory personnel

Air lead (µg/m3)

Blood lead (µg/dL)

09/08/2006

Year(s) of study

P 141-164 DEF.qxp

160

Table 74 (contd)

P 141-164 DEF.qxp

Table 74 (contd) Year(s) of study

Air lead (µg/m3)

Blood lead (µg/dL)

Reference

No. of samples taken

Type of sampling

AMa

Range

8

[29]

8–44

10

PBZ + GA

160

10–290

28

[9]

< 5–43

NR

NR

1988

Motor vehicle parts and accessories

1987–88

Motor vehicle parts and accessories

1989

2

[34]

30–37

2

PBZ

[70]

60–80

Motor vehicle parts and accessories Radiator mechanics Delivery employees

1989

7 5 2

32 38 17.5

17–64 23–64 17–18

4 2

PBZ GA

[28] [55]

10–50 20–90

Motor vehicle parts and accessories Radiator mechanics Delivery employees

1989 4 2

[30] [18]

13–41 14–21

4

PBZ

[98]

30–220

Motor vehicle parts and accessories: mechanics and delivery employees

1989

4

[21]

11–33

3 1

PBZ GA

[43] 90

20–60

Gunter & Hales (1990d)

Nitrogenous fertilizers

1991

13

4–13

9 7

PBZ GA

ND–7 ND–12

Decker & Galson (1991)

Non-ferrous foundries (castings)

1988

18

[34]

4–67

6

PBZ

[294]

38–520

Montopoli et al. (1989)

Police protection (indoor firing range)

1982

NR

NR

5 6

PBZ GA

[1130]d [1120]d

940–1300d 750–1520d

Bicknell (1982)

Police protection (indoor firing range)

1987–88

NR

NR

4

PBZ 8-h TWA

142–2073

102–3361 13–194d

Reh & Klein (1990)

Police protection (indoor firing range)

1991

NR

NR

5

PBZ 8-h TWA

14

7–23 < 3d

McManus (1991)

Police protection (indoor firing range) Student Range officer General area

1991

NR

NR PBZ PBZ GA

26–32d 16–18d

1–116d 0.15–53d 0.15–2450

Police protection (indoor firing range)

1991

5.4d

1–16d

NR

Driscoll & Elliott (1990) Gunter & Hales (1990a) Gunter & Hales (1990b) Gunter & Hales (1990c)

Echt et al. (1992) 26 14 13

NR

Gunter & Hammel (1989)

10

161

Lee & McCammon (1992)

Page 161

Motor vehicle parts and accessories

11:26

Range

INORGANIC AND ORGANIC LEAD COMPOUNDS

AMa

No. of workers tested

09/08/2006

Industry

Industry

Year(s) of study

Air lead (µg/m3)

Blood lead (µg/dL) AMa

Range

No. of samples taken

Type of sampling

AMa

Range

NR

16

PBZ

ND–8d

NR

Rinehart & Almaguer (1992)

Police protection (indoor firing range)

1992

NR

NR

3 13

PBZ GA

6d NA

5–7d ND–845

Cook et al. (1993)

Police protection (in- and outdoor firing ranges) Instructor Technician Gunsmith Custodian

1989–91

Police protection (indoor firing range) 1997 (during shooting) 1998 (during shooting)

1997–98

Pressed and blown glass and glassware

1984

Pressed and blown glass and glassware Pressed and blown glass and glassware

Barsan & Miller (1996) 7–14 5 5–11 6

8–15 10–16 11–12 <4

NR

NR

< 4–27 6–28 < 4–24

NR 12 18 3

PBZ PBZ PBZ PBZ

12.4 0.6 0.6 NA

ND–52 ND–2.7 ND–4.5 ND–220

9 20 8

PBZ + GA PBZ + GAe PBZ + GAf

144d 230d 433d

4–190d ND–640d 100–960d

PBZ GA

52 75

30–60 70–80

Gunter & Thoburn (1985)

PBZ + GA

NA

ND–80

Gunter (1987)

GA

[17]

1.6–51

Hall et al. (1998)

PBZ + GA

NA

< 3–60

Gunter & Seligman (1984)

Harney & Barsan (1999)

12

20

2–36

4 2

1986

9

13

4–33

16

1997

NR

NR

Primary smelting and refining of copper

1984

49

11

0–24

15

Secondary smelting and refining of nonferrous metals

1989

12

29

5–63

5 2

PBZ GA

NA NA

< 2–40 < 2–50

Gunter & Daniels (1990)

Primary and secondary smelting and refining of non-ferrous metals

1981

3

32

26–37

6 9

PBZ GA

123 NA

5–295 ND–1334

Apol (1981)

Refuse systems

1990–91

NR

NR

6 4

PBZ GA

NA NA

ND–30d ND–30d

Mouradian & Kinnes (1991)

Scrap and waste materials

1987

6

PBZ + GA

NA

ND–2.3

Hills & Savery (1988)

Scrap and waste materials

1991

15

66

9–86

NR

Gittleman et al. (1991)

Scrap and waste materials

1993

16

20

4–40

NR

Malkin (1993)

7

4–33

10

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Reference

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Table 74 (contd)

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NR

NR

Shipbuilding and repairing

1985

10

38

Shipbuilding and repairing

1994

NR

NR

Shipbuilding and repairing

1997

67

4.4

Special trade contractors: cleaning of leadbased paint

1992

NR

NR

Steel works, blast furnaces (including coke ovens)

1984

26

33

Steel works, blast furnaces (including coke ovens)

1980–82

79

8–15

Steel works, blast furnaces (including coke ovens)

1989

22

Steel works, blast furnaces (including coke ovens)

1990

Storage batteries

1983–84

Storage batteries Location 1

1987

No. of samples taken

Type of sampling

AMa

Range

McGlothlin et al. (1999) 4 5 5 4

PBZ PBZ PBZ PBZ

[355] [189] [198] NA

253–435 41–399 79–356 < 0.6–2.5

7

PBZ

257

108–500

Landrigan & Straub (1985)

PBZ-ST

[133]

3–900

Sylvain (1996)

PBZ

32

0–1071

Kiefer et al. (1998)

36 5 18

PBZ-ST PBZ GA-ST

66 30 44

5–360 6–73 4–180

Sussell et al. (1993)

27

PBZ

40

< 3–190

Gunter & Thoburn (1984)

42

NR

NR

NR–79

Hollett & Moody (1984)

18

20

PBZ

12

< 3–31

Lee et al. (1990b)

NR

NR

12

[PBZ]

[16]

1.3–44.2

Tubbs et al. (1992)

317

10–39

3–58

675

PBZ

30

1–1600

Singal et al. (1985)

27

31–47

NR–64

12 6

65c 28–> 60

NR–89

26 2 10 3 3

PBZ GA PBZ PBZ GA

[652] [7] [860] [100] [57]

40–5300 4–10 50–3400 30–190 10–100

25–53

14 0–18

1–33

347

Matte & Burr (1989a)

1987

23

64c

28–86

7

PBZ

21c

NR–66

Matte & Burr (1989b)

Storage batteries

1991

43

41

12–66

12 2

PBZ GA

[276] [59]

9–846 10–107

Clark et al. (1991)

163

Storage batteries

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Range

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No. of workers tested Ship breaking, ship repair, dismantling ships Inside a ship Process area Inside barge tank Under a barge

Location 2 Location 3

Air lead (µg/m3)

Blood lead (µg/dL)

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Industry

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Industry

Year(s) of study

Type of sampling

AMa

Range

19 4 12 5 7 8 3 6

PBZ GA PBZ GA PBZ GA PBZ GA

291

68–495 1–165 15–418 13–39 31–77 11–51 12–43 16–141

22

PBZ

[352]

23–1970

McCammon et al. (1992)

No. of samples taken

30–43

First assembly Pouching Grid casting 23

4–38

Esswein et al. (1996)

108 50

Tanks, fabricated plate work

1991

22

Valves and pipe fittings

1981

2

< 30

2

PBZ

[45]

10–80

Ruhe (1982a)

Valves and pipe fittings

1981

2

< 30

2

PBZ

[839]

321–1356

Ruhe (1982b)

AM, arithmetic mean; PBZ, personal breathing zone; NA, not applicable; ND, not detected; NIOSH, National Institute for Occupational Safety and Health (USA); NR, not reported; GA, general area; ST, short-term; TWA, time-weighted average; LT, long-term; [....] calculated by the Working Group a Unless otherwise stated b Highest value probably a contaminated sample; next highest values at 202 µg/m3 c Geometric mean d 8-h TWA value calculated from a short-term sample, assuming no other lead exposure during the day than during sampling e Measured with 37-mm cassette f Measured with Institute of Occupational Medicine (IOM) sampler

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No. of workers tested Storage batteries Pasting operation

Air lead (µg/m3)

Blood lead (µg/dL)

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Lead–acid battery workers

Blood lead concentrations have been studied most extensively in workers in lead storage-battery factories (Table 66). Occupational exposure to lead may occur during the production of lead–acid batteries, when grids are manufactured either by melting lead blocks and pouring molten lead into molds or by feeding rolled sheets of lead through punch presses. In addition, a lead oxide paste is applied into grid spaces. Average lead concentrations in blood were generally in the range 20–45 µg/dL. Particularly high concentrations (> 65 µg/dL) were detected in workers engaged in grid casting in a study in Iraq (Mehdi et al., 2000), in workers at several workstations in a study from Israel (Richter et al., 1979) and in a study in Taiwan, China (Wang et al., 2002b). (b)

Workers in mining and primary smelting

The most commonly mined lead ore is galena (87% lead by weight), followed by anglesite (68%) and cerussite (78%). Workers in lead smelter and refinery operations such as sintering, roasting, smelting and drossing are exposed to lead sulfide, sulfates and oxides. Miners of copper and zinc also are exposed to lead. Relatively high blood lead concentrations (> 60 µg/dL) have been recorded in such workers, in particular in two studies in Nigeria (Adeniyi & Anetor, 1999) and in Uruguay (Pereira et al., 1996) (Table 67). (c)

Workers in secondary smelting

Battery-recycling workers in secondary smelters are exposed to lead as they convert used batteries and other leaded materials to lead of varying purity. From Table 68, it appears that the mean blood lead concentrations reported for workers in secondary lead smelters were higher than for workers in other occupations (see Tables 66–73). Of the different job categories within secondary smelting, the highest mean blood lead concentrations (87 µg/dL) were observed in workers in charge of furnace operation (Wang et al., 1998). In some individual workers, blood lead concentrations in excess of 150 µg/dL were measured (Makino et al. 1994). (d)

Workers in leaded-glass manufacturing

Leaded glassware is made by combining lead oxide compounds with molten quartz. This process results in lead fumes and dusts, and glass-blowing is an additional activity that involves potential contact with lead. Production of leaded glass has been associated with high lead exposure, with mean blood lead concentrations in excess of 50 µg/dL in all studies (Table 69). (e)

Workers in welding/soldering

Typical solders contain 60% lead and the high temperatures involved in flame solder work volatilize some of this lead. Workers repairing vehicle radiators are exposed to lead

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dusts during radiator cleaning in addition to lead fumes during flame soldering (Tharr, 1993). Surveys on welding work in radiator-repair workers (Table 70) generally showed mean blood lead concentrations in the range of 10–35 µg/dL. A study of 56 mechanics working in radiator shops in the Boston area, USA, reported that 80% had blood lead concentrations greater than 30 µg/dL and 16 had concentrations > 50 µg/dL (Goldman et al., 1987). Relatively high blood lead concentrations (up to 47 µg/dL) were also reported among women engaged in soldering in an electronics plant (Makino et al., 1994). Welders are exposed to lead in the welding fumes generated by gas metal arc welding of carbon steel. However, in one study, lead concentrations in the welding fumes were found to range from 1.0 to 17.6 µg/m3, well below the established permissible exposure limit for the workplace (Larson et al., 1989). (f)

Professional drivers and traffic controllers

Professional drivers (e.g. taxi and bus drivers) and traffic policemen are exposed to lead in ambient air from vehicle exhausts (Table 71). The blood lead concentrations reported are distributed over a wide range, from 10 µg/dL (Zhou et al., 2001) to > 60 µg/dL (Ahmed et al., 1987), probably as a result of variations in traffic intensity and use of leaded gasoline. (g)

Firing-range instructors

Lead exposure associated with the discharge of firearms at indoor firing ranges began to be monitored in the early 1970s. Over the last 20 years, numerous exposure assessments have been performed at both indoor and outdoor firing ranges (Table 72). Several sources of airborne lead have been identified: fragmentation of bullets during firing; the explosive vaporization of the primer, which can contain both lead styphnate and lead peroxide; and inadequate ventilation of the range (Landrigan et al., 1975b; Fischbein et al., 1979; Muskett & Caswell, 1980; Dams et al., 1988). Instructors are generally exposed to the highest concentrations of airborne lead and tend to have the highest blood lead concentrations due to their regular duties, which include supervising the range, cleaning and test-firing weapons, and preparing training ammunition from commercially purchased components. A positive correlation was reported between exposure of firearms instructors to elemental lead at covered outdoor firing ranges and increased blood lead concentrations (Tripathi et al., 1991). Concentrations of airborne lead can be significantly reduced (97–99%) by using a lead-free primer and bullets jacketed with nylon, brass or copper (Valway et al., 1989; Robbins et al., 1990; Tripathi et al., 1990, 1991; Goldberg et al., 1991; Löfstedt et al., 1999; Bonanno et al., 2002). (h)

Other occupational exposures

Several studies have found elevated blood lead concentrations in other occupational settings, such as in employees working in automobile garages. Mean blood lead

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concentrations in children working in petrol storage bunkers in India for more than one year were almost double (39.3 ± 3.7 µg/dL) those of age-matched unexposed children (23.1 ± 0.5 µg/dL) (National Institute of Nutrition, 1995–1996). Silver jewellery workers are exposed to high concentrations of lead and may have blood lead concentrations > 200 µg/dL (Behari et al., 1983; Kachru et al., 1989). People working in arts and crafts may be exposed to lead in paints, ceramic glazes and lead solder used in sculpture and stained glass (Hart, 1987; Fischbein et al., 1992). Newspaper printing has been associated with lead exposure (Agarwal et al., 2002). In one study, more than 3/4 of the monocasters showed some clinical symptoms of lead poisoning (Kumar & Krishnaswamy, 1995a). Where computerized printing techniques have replaced the traditional printing techniques, however, lead exposure is no longer a significant concern in this profession. 1.5

Analysis

Analysis of lead and lead compounds in various matrices has been reviewed (Fitch, 1998). 1.5.1

Environmental samples

Although lead occurs in the environment in the form of a range of inorganic or organic compounds, it is always measured and expressed as elemental lead. Determination of lead in environmental samples requires sample collection and sample preparation, often by wet or dry ashing or acid digestion to solubilize lead in aqueous solution before analysis. Care must be taken during sampling and sample preparation to avoid contamination or loss of lead (WHO, 1995). The techniques most commonly used for the analysis of particulate lead and inorganic lead compounds in air, water, dust, sediments, soil and foodstuffs include flame atomic absorption spectrometry (AAS), graphite furnace–atomic absorption spectrometry (GF– AAS), inductively coupled plasma–mass spectrometry (ICP–MS), inductively coupled plasma–atomic emission spectrometry (ICP–AES), anode-stripping voltametry (ASV) and X-ray fluorescence (XRF). Organic lead species such as tetramethyl lead and tetraethyl lead can be trapped cryogenically or by liquid or solid sorbents. Gas chromatography (GC) coupled with GF–AAS or photoionization detection (PID) can be used to differentiate between organic lead species (Birch et al., 1980; De Jonghe et al., 1981; Chakraborti et al., 1984; NIOSH, 1994a; ATDSR, 1999). Selected methods used for the analysis of lead in various matrices are presented in Table 75.

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Table 75. Selected methods for analysis of lead in various matrices Matrix

Methoda

Detection limit

Method number

Referenceb

Air

Flame AAS GF–AAS ICP–AES ASV XRF AAS or AES ICP–AES ICP–AES

Method 7082 Method 7105 Method 7300 Method 7701 Method 7702 Method ID-121

NIOSH (1994b) NIOSH (1994a) NIOSH (2003a) NIOSH (2003b) NIOSH (1998) OSHA (2002a)

Method ID-125G Method ID-206

OSHA (2002b) OSHA (2002c)

XRF

2.6 µg/sample 0.02 µg/sample 0.062 µg/sample 0.09 µg/sample 6 µg/sample 0.01 µg/mL (qual.) 0.05 µg/mL (anal.) 2.1 µg/sample (qual.) 0.071 µg/mL (qual.) 0.237 µg/mL (quant.) 22 µg/sample

Method OSS-1

OSHA (2003)

GC–PID

0.1 µg/sample

Method 2533

NIOSH (1994c)

Air (TML)

GC–PID

0.4 µg/sample

Method 2534

NIOSH (1994d)

Water

ICP–AES ICP–MS XRF AAS

42 µg/L 0.08 µg/L 1 µg/L 100 µg/L

Method D1976 Method D5673 Method D6502 Method 239.1

ASTM (2002) ASTM (2003a) ASTM (2003b) US EPA (1978)

Ambient water

ICP–MS GF–AAS ICP–MS

0.0081 µg/L 0.036 µg/L 0.015 µg/L

Method 1640 Method 1637 Method 1638

US EPA (1997a) US EPA (1996c) US EPA (1996d)

Marine water

GF–AAS ICP–MS

2.4 µg/L 0.074 µg/L

Method 200.12 Method 200.10

US EPA (1997b) US EPA (1997c)

Soil, wastes and groundwater

AAS GF–AAS

100 µg/L 1 µg/L

Method 7420 Method 7421

US EPA (1986b) US EPA (1986c)

Marine sediment and soils

GF–AAS ICP–MS XRF

0.2 µg/g 0.15 µg/g 0.2 µg/g

Method 140.0 Method 172.0 Method 160.0

NOAA (1998a) NOAA (1998b) NOAA (1998c)

Aqueous and solid matrices

ICP–AES

28 µg/L

Method 6010C

US EPA (2000)

Food

GF–AAS AAS

0.1 mg/kg NR

Method 999.10 Method 972.25

AOAC (2000a) AOAC (2000b)

Evaporated milk and fruit juice

ASV

5 ng/sample

Method 979.17

AOAC (2000c)

Sugars and syrups

GF–AAS

3.3 µg/kg

Method 997.15

AOAC (2000d)

Edible oils and fats

GF–AAS

18 µg/kg

Method 994.02

AOAC (1994)

c

Air (TEL)

d

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Table 75 (contd) Matrix

Methoda

Detection limit

Method number

Referenceb

Ceramic foodware

AAS GF–AAS

NR NR

Method 4-1 Method 4-2

US FDA (2000a) US FDA (2000b)

Paint, soil, dust, air

ICP–AES AAS GF–AAS

Variable, NR Variable, NR Variable, NR

Method E1613

ASTM (1999)

NR, not reported a AAS, atomic absorption spectrometry; ASV, anode-stripping voltametry; GD–PD, gas chromatography–photoionisation detector; GF–AAS, graphite furnace atomic absorption spectrometry; ICP– AES, inductively-coupled plasma atomic emission spectrometry; ICP–MS, inductively-coupled plasma mass spectrometry; XRF, X-ray fluorescence b NIOSH, National Institute for Occupational Safety and Health; OSHA, Occupational Safety and Health Administration; ASTM, American Society for Testing and Materials; AOAC, Association of Official Analytical Chemists; US EPA, US Environmental Protection Agency; NOAA, National Oceanic and Atmospheric Administration; US FDA, US Food and Drug Administration c TEL, tetraethyl lead d TML, tetramethyl lead

Use of lead isotope ratios in source attribution and apportionment Stable lead isotopes have been used to identify the source(s) of lead in environmental and biological samples (source attribution and apportionment). Lead isotopes vary over geological time because they are the end-product of radioactive decay of uranium and thorium. Thus, lead deposits of different geological age have different lead isotope ratios; e.g. the major Broken Hill lead–zinc–silver mine deposit in Australia formed approximately 1700–1800 million years ago has an isotope ratio expressed as the 206Pb/204Pb ratio of 16.0. In contrast, geologically younger deposits formed approximately 400–500 million years ago, found on the same continent and in various places around the world, have a 206Pb/204Pb ratio of about 18.0 (Gulson, 1986, 1996a). Techniques have been developed to measure lead isotope ratios in environmental and biological samples. Lead is extracted from samples by acid digestion and separated from potentially interfering cations (iron, zinc) by anion-exchange chromatography. Lead isotopes are measured as ratios (e.g. 208Pb/206Pb, 207Pb/206Pb, 206Pb/204Pb) by solid source thermal ionization–mass spectrometry or ICP–MS (Franklin et al., 1997; Eades et al., 2002). Lead in the environment and in humans (and animals) is often a mixture of lead originally derived from different mines, and it is possible to estimate the relative contribution of the different sources. Where there are two major sources, the estimation is straightforward. For example, if the lead present in a blood sample with a 206Pb/204Pb ratio of 17.5 comes from two major sources, the skeleton (ratio of 17.0) and diet (ratio of 18.0), there is an equal contribution to blood from both sources. For three or more sources, the attribution

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becomes more complex and requires application of specialized computational procedures (Franklin et al., 1997). 1.5.2

Biological indicators of lead contamination in soil and water

Lead affects many physiological parameters in plants (Singh et al., 1997). Plants and some fungi synthesize cysteine-rich low-molecular-weight peptides called phytochelatins (class III metallothioneins) in response to heavy metal stress (Grill et al., 1985). Phytochelatins have the general structure (γ-Glu-Cys)n-Gly (n = 2–11); the majority of legumes (of the order Fabales), on the other hand, synthesize homophytochelatins in which the carboxy-terminal glycine is replaced by β-alanine (Grill et al., 1986). For example, when exposed to lead, roots of Vicia faba synthesize phytochelatins, Phaseolus vulgaris synthesizes homophytochelatins, and both phytochelatins and homophytochelatins are induced in Pisum sativum (Piechalak et al., 2002). These peptides are involved in accumulation, detoxification and metabolism of metal ions including lead (Grill et al., 1985; Mehra & Tripathi, 2000). Phytochelatins detoxify metal by thiolate coordination (Grill et al., 1987). They are synthesized enzymatically from glutathione or its precursor by the enzyme γ-glutamyl cysteine dipeptidyl transpeptidase, also called phytochelatin synthase; the enzyme is present constitutively in cells and is activated by heavy metal ions (Grill et al., 1989). Thus, phytochelatins are synthesized enzymatically in response to exposure to many metals including lead (Grill et al., 1987; Scarano & Morelli, 2002). Phytochelatins can be detected by high-performance liquid chromatography (HPLC) (Grill et al., 1991) and thus have the potential to be used as plant biomarkers of heavy metal contamination of soil and water. There are ample laboratory and field data indicating that phytochelatins are biological indicators of exposure to metals, including lead (Ahner et al., 1994; Pawlik-Skowronska, 2001; Pawlik-Skowronska et al., 2002). 1.5.3

Biological samples

Lead distribution between blood, soft tissue and hard tissue is complex (see Section 4.1 for details). The time required for equilibration of lead between tissues is dependent upon the type of tissue and varies from hours to decades. In addition, equilibration between tissues is subject to a variety of physiological states that affect bone metabolism. Hence, exposure to lead can be estimated by the analysis of various human tissues, either directly for lead or indirectly for biomarkers of exposure to lead. The tissues include blood, plasma, urine, saliva, bone, teeth, nails and hair. The following section summarizes the methods used for the direct determination of lead in tissues and the indirect determination of exposure to lead using biomarkers. Methods that measure distribution of lead throughout the body are discussed in Section 4.1.

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Analysis in hard tissues

(i) Bone Exposure to lead over time results in the progressive accumulation of lead, predominantly (> 95% of total lead burden) in bones (Barry, 1975). Hence, the analysis of lead in bones is a suitable approach to determine exposure to lead during the lifetime of an individual. Using GF–AAS to measure lead concentrations in bone tissue from individuals from prehistoric and modern times, it has been estimated that the body burden of lead in humans in the late 20th century is more than twice that of the late Roman times (Drasch, 1982). Since GF–AAS analysis cannot be performed on human bone in vivo, various XRF methods have come into use as a direct measure of lead in bone (Todd & Chettle, 1994). XRF is based on the property of lead to emit X-rays when it is exposed to photons of an appropriate energy; the fluorescence from lead accumulated in bone provides a low-risk, non-invasive measure of total lead content. In the 1990s, XRF analysis was limited to research institutions and was deemed unlikely to become a useful screening tool for exposure to lead (Todd & Chettle, 1994). Intrinsic variability in the instruments used, variability of lead deposition between the two main compartments of bone (cortical versus trabecular), patients’ bone density and the use of a minimal detectable limit all increase the complexity of data analysis in epidemiological studies (Hu et al., 1995; Kim et al., 1995b). Efforts continue to improve understanding of the variables that affect the XRF signal (Hoppin et al., 2000; Todd et al., 2000a, 2001b) and to use XRF for meaningful epidemiological analysis (Hoppin et al., 1997; Roy et al., 1997; Markowitz & Shen, 2001). XRF has been used successfully to study the factors involved in the mobilization of lead from bone (Schwartz et al., 1999; Oliveira et al., 2002). With the understanding that bone lead is probably the best overall indication of lifetime exposure to lead (Börjesson et al., 1997; Hu, H. et al., 1998), it is reasonable to consider application of XRF to the analysis of the contribution of exposure to lead to the development of cancer. (ii) Teeth The dentin of shed deciduous teeth (also known as baby teeth) is a suitable source for analysis of prior and current lead exposure in children during their teeth-shedding years (Gulson, 1996a; Kim et al., 1996a) but this method suffers from the limited availability of samples. It has been estimated that deciduous tooth lead (measured in ppm or µg/g) correlates with about half the value of blood lead (measured in µg/dL), but that this correlation does not hold for the permanent, adult teeth (Rabinowitz, 1995). The studies to determine lead concentrations in teeth each include a specific method for digestion of the tooth, followed by analysis of lead by ASV, ICP–MS or AAS. (iii) Hair and nails Available data on analysis of lead in hair can be divided into three groups. The first group of studies describe hair analysis as a general toxicological screen for heavy metals. In this case, the primary concerns are sample preparation, i.e. washing, with the intent to remove surface contamination. A recent study of six commercial laboratories advertising

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multimineral hair analysis showed high variability between laboratories, thus giving cause for concern about the validity of these results (Seidel et al., 2001). The second use of hair lead analysis has been for patients suspected of having chronic, mild or subacute lead poisoning (Kopito et al., 1967). The third documented use is in epidemiologial studies (Tuthill, 1996). However, an analysis of the distribution of heavy metals in tissues of 150 corpses concluded that hair was not an appropriate tissue for monitoring exposure to lead (Drasch et al., 1997). In general, the available data do not support the use of hair as a resource for analysis of exposure to lead. The use of nails seems attractive as a non-invasive approach to determining exposure to lead. However, lead concentrations in nails is not a reliable indicator of exposure to lead (Gulson, 1996b). (b)

Analysis in soft tissues and body fluids

(i) Blood The benchmark for analysis of lead exposure is the determination of blood lead concentrations by AAS. Using this method, lead is typically reported in µg/dL, which can be converted to concentration in µM (µmol/L) by dividing the value reported in µg/dL by 20.7. Analytical methods have changed over time because health-based standards and guidelines have changed. For example, the intervention level set by CDC in the USA has dropped from 60 µg/dL to 35 µg/dL in 1975, to 25 µg/dL in 1985, and to 10 µg/dL in 1991 (CDC, 1991). Analytical methods used to determine lead concentrations in whole blood detect both the lead associated with proteins in the erythrocytes and that in the plasma (Everson & Patterson, 1980; Cake et al., 1996; Manton et al., 2001). The relationship between lead in whole blood, in erythrocytes and in plasma is discussed in detail in Section 4.2.1. Lead in blood is in equilibrium between the plasma and the erythrocytes. Since the plasma fraction has a greater bioavailability than the lead pool in the red blood cells and is in equilibrium with extravascular compartments, the lead content of plasma should be considered to be a better estimate of the internal dose than the concentration of the metal in whole blood (Cavalleri & Minoia, 1987; Schütz et al., 1996). To obtain an accurate quantification of low concentrations of lead in plasma, Everson and Patterson (1980) introduced the technique of isotope-dilution mass spectrometry and concluded that prior studies had grossly overestimated the amount of lead in the plasma compartment of blood. ICP–MS was also shown to be sensitive enough for monitoring low concentrations of plasma lead, and plasma samples could be frozen prior to analysis without any alteration in the analytical results (Schütz et al., 1996). As whole blood became the material of choice for the determination of lead exposure, various atomic absorption techniques were introduced and evaluated for this purpose. By the late 1980s, the popularity of GF–AAS stemmed from its high sensitivity (0.05 µg/dL) and small sample-size requirements (< 50 µL); however, there was considerable variation

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in the different sample preparation techniques and an optimal method could not be defined (Subramanian, 1989). By 2001, commercial laboratories used predominantly electrothermal atomization atomic absorption spectroscopy, ASV and ICP–MS (Parsons et al., 2001). A comparison of GF–AAS and ICP–MS performed in a Japanese laboratory showed the two methods to be equally sensitive but the latter took only one fifth of the time. ICP–MS results tended to be 10–20% lower than those obtained by atomic absorption analysis (Zhang et al., 1997c). For screening purposes, the simplest blood lead test is conducted with a capillary blood sample obtained from a finger-prick. Concerns over false positives due to skin surface contamination with environmental lead dust have resulted in the recommendation that a positive capillary blood lead test result be followed by a test on venous blood. Following the recommendation of universal screening of children in the USA (CDC, 1991; American Academy of Pediatrics, 1998), an analysis of the cost effectiveness of strategies for screening of lead poisoning concluded that a screening method based on direct analysis of venous blood was the least expensive (Kemper et al., 1998). Other studies have shown an excellent correlation between the results of capillary blood lead analysis and venous blood lead analysis, thus advocating the former as an appropriate method for screening purposes (Parsons et al., 1997). Regardless of the method chosen, blood lead analysis is the only diagnostic for lead exposure for which there exists an international standard for quality control (ACGIH, 2001; WHO, 1996; see Section 1.6) and an external quality assurance programme (Schaller et al., 2002). (ii) Urine Urine is a readily available biological sample for the direct analysis of lead content by AAS. This method has been used successfully to monitor relative levels of exposure in workers with chronic occupational exposure to lead (Vural & Duydu, 1995; Jin et al., 2000). One study argued against the routine use of urine as a surrogate for blood lead analysis because of the poor correlation between the two values on an individual person basis, particularly at blood lead concentrations < 10 µg/dL (Gulson et al., 1998b). (iii) Placenta During development of biomonitoring methods, non-invasive tissue acquisitions are frequently sought and analysis of lead in placental tissue has been suggested and evaluated as a possible indicator of exposure. However, studies show that placenta is not a suitable tissue for exposure monitoring, because lead is not distributed uniformly throughout the tissue (Lagerkvist et al., 1996a). (iv) Sweat and saliva Lead concentrations in sweat and saliva have been evaluated and are not recommended for exposure monitoring because of the poor correlation with blood lead concentrations (Lilley et al., 1988; Koh et al., 2003).

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Biomarkers of lead exposure (a)

Biomarkers related to haeme biosynthesis

It has long been known that lead interferes with haeme biosynthesis (Chisolm, 1964; Lamola & Yamane, 1974). Aberrations in the haeme biosynthetic pathway form the basis for many of the methods used for biomonitoring of human exposure to lead. Haeme is the tetrapyrrole cofactor component of haemoglobin responsible for direct binding of oxygen. An early step in the pathway of haeme biosynthesis is the synthesis of the monopyrrole porphobilinogen from δ-aminolevulinic acid (ALA). This reaction is catalysed by the enzyme porphobilinogen synthase (PBGS) also commonly known as δaminolevulinate dehydratase (ALAD). Despite the fact that the recommended IUPAC name is PBGS, ALAD is still commonly used in the clinical literature. The inhibition of PBGS by lead manifests itself in a decrease in measurable PBGS activity in blood and an accumulation of the substrate ALA in serum, plasma and urine. Porphobilinogen continues on the pathway to haeme through the action of additional enzymes to form the immediate haeme precursor protoporphyrin IX, also called free protoporphyrin, erythrocyte protoporphyrin (EP) or, erroneously, zinc protoporphyrin (ZPP). Insertion of iron into protoporphyrin IX is then catalysed by the enzyme ferrochelatase to form haeme. When iron is lacking, ferrochelatase inserts zinc into protoporphyrin IX to form ZPP. There is a tight and not fully understood interrelationship between haeme biosynthesis and iron homeostasis such that exposure to lead is seen to increase ZPP (Labbé et al., 1999). Hence, between 1974 and 1991, measurement of ZPP was the method recommended by CDC in the USA for screening for exposure to lead (CDC, 1975). One limitation in using these biomarkers is that they can be perturbed by conditions other than exposure to lead. The correlation between these biological parameters and a direct measure of blood lead may include significant scatter (Oishi et al., 1996b) and may not be useful at low blood lead concentrations (Schuhmacher et al., 1997). There are both genetic and environmental factors other than lead that can effect ALA in urine or serum, PBGS activity in blood and ZPP in blood (Moore et al., 1971; Labbé et al., 1999; Kelada et al., 2001). (i) PBGS (ALAD) activity in blood PBGS activity in blood is the most sensitive biomarker of lead exposure (Toffaletti & Savory, 1976; Schuhmacher et al., 1997). Human PBGS is a zinc metalloenzyme in which the catalytically essential zinc is in an unusually cysteine-rich environment that has a very high affinity for lead relative to the corresponding region in other zinc metalloenzymes. Although the activity of PBGS in blood shows normal biological variation, a comparison of the enzyme activity before and after various treatments that displace the inhibiting lead enables the determination of lead-specific enzyme inhibition (Granick et al., 1973; Chiba, 1976; Sakai et al., 1980). The PBGS assay is either a colorimetric determination of the complex of porphobilinogen with Ehrlich’s reagent (Berlin & Schaller, 1974) or a quantification by HPLC of the porphobilinogen formed (Crowne et al., 1981). Despite the sensi-

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tivity of PBGS to inhibition by lead, determination of the enzyme activity is not widely used in the clinical setting to determine lead exposure. In part, this is due to the fact that the inhibition of PBGS activity is only observed at low levels of exposure and reaches a plateau above 50–80 µg/dL lead (Toffaletti & Savory, 1976). The PBGS assay also gained a reputation for being complex and irreproducible. This may be due to the fact that the enzyme recovers its activity during the assay procedure, thus producing a variation in specific activity with incubation time (Jaffe et al., 1991, 2001). Because assays used clinically require the analysis of a stopped mixture, a fixed incubation time is used, which may vary between laboratories. PBGS in erythrocytes has a very high affinity for lead (Simons, 1995) and an individual’s allotype for the gene encoding PBGS appears to affect the percentage of lead bound by the protein (Bergdahl et al., 1997). Hence, a variety of epidemiological studies have suggested that an individual’s PBGS allotype affects the pharmacodynamics of lead poisoning (Sakai, 2000). PBGS activity in blood can also be affected by the condition of hereditary tyrosinaemia, wherein an aberrant metabolic by-product of tyrosine acts as a PBGS inhibitor (Lindblad et al., 1977) (see Section 4.2). (ii) ALA in urine and plasma Haeme precursors in urine were among the first biomarkers used for detection of lead intoxication. The synthesis of ALA is the primary regulatory target for haeme biosynthesis: haeme down-regulates ALA synthase expression directly by decreasing the half-life of ALA synthase mRNA (Hamilton et al., 1991). Thus, inhibition of PBGS by lead, which results in a decrease in haeme biosynthesis, will upregulate ALA biosynthesis, and increase ALA concentrations in plasma and urine. An increased concentration of plasma ALA in turn increases the affinity of zinc for PBGS, thus giving some reprieve from the lead-induced inhibition of PBGS (Jaffe et al., 2001). This interrelationship between lead, PBGS and ALA contributes to the complex clinical correlations between lead exposure and accumulation of ALA in urine. ALA concentrations in plasma increase slowly below blood lead concentrations of 40 µg/dL and rapidly above this concentration. Significant correlations are found in both the slow and rapid phases (Sakai, 2000). Plasma ALA (expressed in µg/L) is generally found to be about five times the value measured in urine (expressed in mg/g creatinine) (Oishi et al., 1996b). Analysis of ALA in biological fluids is generally performed either by colorimetry after chemical transformation of ALA into an Ehrlich’s-positive pyrrole (Tomokuni & Ichiba, 1988a) or by fluorometry after HPLC analysis using pre- or post-column derivatization (Tabuchi et al., 1989; Okayama et al., 1990; Oishi et al., 1996b). (iii) Zinc protoporphyrin in blood In the 1970s, the CDC approved ZPP as the preferred biomarker for the monitoring of lead exposure in the USA. The approved assay used spectrofluorometry, could readily be carried out on-site and was widely adopted for screening childhood lead poisoning. However, ZPP is generally not elevated in individuals with blood lead concentrations

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below 30 µg/dL (Schuhmacher et al., 1997). With the current cut-off for lead poisoning in young children being 10 µg/dL blood lead (CDC, 1991), ZPP has generally fallen out of favour in the USA. Although ZPP is not expected to be elevated in individuals casually exposed to low concentrations of lead, it continues to be a valuable tool for monitoring occupational exposure (Lee, 1999; Sakai, 2000) and bioresponse to lead (Lauwerys et al., 1995). Also, elevation of ZPP is a diagnostic commonly used to detect iron deficiency (Labbé et al., 1999). (b)

Biomarkers related to pyrimidine nucleotide metabolism

Although it has received far less attention than PBGS, the enzyme pyrimidine 5′-nucleotidase (P5′N), also known as uridine monophosphate hydrolase-1, is extremely sensitive to inhibition by lead (Paglia & Valentine, 1975). As with other biomarkers, both genetic and environmental factors can affect P5′N activity (Rees et al., 2003). By analogy to the clinical manifestations of hereditary deficiencies in P5′N, the majority of the haematological features of lead poisoning can be explained by inhibition of P5′N (Rees et al., 2003). Although not yet widely used, recent studies suggest that P5′N activity in blood is an excellent biomarker for exposure to lead, although less sensitive than PBGS (Kim et al., 1995a). The three-dimensional structure of human P5′N is not yet known, but the documented sequence contains a cysteine-rich cluster (Amici et al., 2000), which may be the site of lead binding. P5′N catalyses the hydrolysis of pyrimidine nucleoside 5′-monophosphate to pyrimidine nucleoside and monophosphate (inorganic phosphate). Assays for P5′N activity fall into two categories. Colorimetric assays are based on the determination of inorganic phosphate. These tests require pre-assay sample dialysis and/or lengthy assay times and are not used for monitoring purposes (Sakai, 2000). Assays based on determining pyrimidine nucleosides have been introduced, using either a radiolabelled nucleoside (Torrance et al., 1985) or HPLC analysis of the liberated pyrimidine nucleoside (Sakai & Ushio, 1986). A significant correlation was reported between log P5′N and blood lead concentrations over the range of 3–80 µg/dL (Sakai, 2000). Measurements of concentrations of pyrimidine nucleosides in blood have been suggested as alternative biomarkers for exposure to lead (Sakai, 2000). (c)

Other biomarkers

Nicotinamide adenine dinucleotide synthetase activity in blood has been suggested as a biomarker for exposure to lead, but this method has received little attention apart from the work of Sakai (2000). Recent investigations into the biological chemistry of lead suggest that lead can bind to a variety of proteins that normally bind zinc and/or calcium, most notably transcription factors. These observations may lead to the future development of alternative biomarkers for measurement of exposure to lead (Godwin, 2001).

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Regulations and guidelines

Regulations and guidelines for lead concentrations in blood in non-occupationally exposed populations, ambient air and drinking-water have been defined in many countries and are given in Table 76. Regulations and guidelines for occupational exposure to lead and lead compounds from several countries are presented in Table 77; maximum permissible lead concentrations in blood of occupationally exposed populations for several countries are presented in Table 78. Many countries have set guidelines for lead in drinking water, gasoline, paint, foods, industrial emissions, and other products such as ceramic-ware and solder (Consumer Product Safety Commission, 1977; US DHUD, 1987; OECD, 1993; US Food and Drug Administration, 1994). JECFA first evaluated lead in 1972, when a provisional tolerable weekly intake of 50 µg/kg bw was established. The value was reconfirmed by the Committee in 1978. In 1986, a provisional tolerable weekly intake of 25 µg/kg bw was established for infants and children for lead from all sources. This value was extended to the general population in 1993 and was reconfirmed in 1999 (WHO, 2000b; JECFA, 2002). Analytical methods have changed over time (see Section 1.5) because health-based standards and guidelines have changed. A historical review of the CDC guidelines in the USA shows a progressive downward trend in tiered screening and intervention guidelines for childhood lead poisoning. Maximum permissible blood lead concentrations in the USA dropped from 35 µg/dL in 1975 to 25 µg/dL in 1985 to 10 µg/dL in 1991 (CDC, 1975, 1985, 1991). Efforts to maintain this downward trend (Bernard, 2003) may continue to drive development of increasingly sensitive analytical techniques. The Commission of European Communities reports the following binding biological limit values [maximum allowed lead levels] and health surveillance measures for lead and its ionic compounds: (1) biological monitoring must include measuring the blood lead concentration using absorption spectrometry or a method giving equivalent results. The binding biological limit is 70 µg lead/dL blood; (2) medical surveillance is carried out when exposure occurs to a concentration of lead in air that is greater than 0.075 mg/m3, calculated as a time-weighted average over 40 h per week, or when a blood lead concentration greater than 40 µg/dL is measured in individual workers; (3) practical guidelines for biological monitoring must include recommendations of biomarkers (e.g. ALA, ZPP, ALAD) and biological monitoring strategies (European Commission, 1998). The American Conference of Governmental Industrial Hygienists (ACGIH) recommends a biological exposure index (BEI) for lead in blood of 30 µg/dL. Women of childbearing age whose blood lead exceeds 10 µg/dL are at risk of delivering a child with a blood lead concentration above the current CDC guideline of 10 µg/dL (ACGIH Worldwide, 2003). The ACGIH considers analysis of lead in blood by GF–AAS, ASV or ICP–MS to be sufficiently sensitive for concentrations below the recommended BEI (ACGIH, 2001).

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Table 76. International standards and guidelines for lead concentrations in blood, air and drinking-water Country

Blood (µg/dL)

Air (µg/m3)

Australia

10 (GP)

0.5 (federal) 1.5 (states)

Austria Belgium Brazil Canada

Czech Republic Denmark European Union Finland France Germany India Ireland Israel Italy Japan Mexico Namibia Netherlands New Zealand Norway Republic of Korea Russian Federation Serbia and Montenegro South Africa Spain Sweden Switzerland United Kingdom USA WHO

Drinking-water (µg/L) 10–50 (OECD) 50

2.0 10 (GP)

40a

15 (GP) 10 (C+W)

1.0–2.5 (BC) 2.0 (QC) 5.0 (MB, NF, ON) 0.5 0.4 1.0; 40a 0.5 2.0 2.0

2.0 0.5 2.0

1.5 0.5 1.0 1.5 0.3 100–200 4.0 2.0 10–15 (F) 10 (C) 10 (GP) 20 (GP)

1.0 2.0 1.5

10 10

50 50 50 10 50 40 100 50 50 50 10 50 50 50 50 (OECD) 20 50 50 50–100 50 10 (OECD) 50 (OECD) 50 15 (OECD)a 10

From OECD (1993); International Lead and Zinc Study Group (2000); Ministry of Health, Brazil (2004); IOMC (1998) BC, British Columbia; C, children; F, fetus; GP, general population; MB, Manitoba; NF, Newfoundland; ON, Ontario; QC, Quebec; W, women of childbearing age a Action level

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Table 77. Regulations and guidelines for occupational exposure to lead and lead compounds Country/Agency Lead Argentina Australia Austria Belgium Canada Alberta Ontario Quebec China Czech Republic Denmark European Union Finland France Germany India Ireland Israel Italy Japan Malaysia Mexico Morocco Namibia Netherlands New Zealand Norway Peru Poland Republic of Korea Serbia and Montenegro South Africa Spain Sweden Thailand United Kingdom USA ACGIH NIOSH OSHA

Exposure limit (mg/m3)

Interpretationa

0.15 0.15 (dust and fume) 0.10 (men); 0.02 (women) 0.15 0.15 0.05 (dust and fume) 0.05 (excluding tetraethyllead) 0.15 0.3 (fume) 0.05 (dust) 0.05 0.10 0.15 0.10 (dust and fumes < 10 µm) 0.10 0.15 0.1 (excluding lead arsenate and 8 lead chromate) 0.15–0.20 0.15 (excluding tetraethyl lead) 0.10 (men); 0.05 (women of fertile age) 0.15 0.10 (excluding alkyls) 0.05 0.15 (dust and fume) 0.20 0.15 0.15 (dust and fume) 0.1 (dust and fume) 0.05 0.20 0.05 0.05 0.05 0.15 0.15 0.10 (total) 0.05 (respirable) 0.20 0.15 0.15

TWA TWA TWA TWA

0.05 < 0.1 0.05

TWA (TLV) TWA (REL) TWA (PEL)

TWA TWA TWA Ceiling Ceiling TWA TWA TWA TWA TWA TWA TWA (MAK) STEL (MAK) TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA TWA Ceiling (OES) TWA

179

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Table 77 (contd) Country/Agency

Exposure limit (mg/m3)

Interpretationa

Lead acetate Norway

0.05 (dust and fume)

TWA

Lead hydrogen arsenate (PbHAsO4) Canada Alberta (as As) 0.15 0.45 China, Hong Kong SAR 1.5 (as PbHAsO4) Mexico (as Pb) 0.15 0.45 USA (as As) NIOSH 0.002 OSHA 0.01 Lead arsenate (as Pb3(AsO4)2) Australia 0.15 Belgium 0.15 Canada Quebec 0.15 China 0.05 (dust) New Zealand 0.15 USA ACGIH 0.15 NIOSH (as As) 0.002 OSHA (as As) 0.01 Lead chromate (as Cr) Australia Belgium Canada Alberta Ontario Quebec China China, Hong Kong SAR Finland Germany Malaysia Netherlands New Zealand Norway Spain

TWA STEL TWA TWA STEL Ceiling (REL) TWA (PEL) TWA TWA TWA TWA TWA TWA (TLV) Ceiling (REL) TWA (PEL)

0.05 0.012

TWA TWA

0.05 0.15 0.012 0.012 0.012 0.012 0.05 0.1 (dusts and aerosols) 0.05 (NOSb) 0.012 0.025 0.05 0.02 0.012

TWA STEL TWA TWA TWA TWA TWA TWA (TRK) TWA (TRK) TWA STEL TWA TWA TWA

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Table 77 (contd) Country/Agency

Exposure limit (mg/m3)

Interpretationa

USA ACGIH OSHA

0.012 0.001

TWA (TLV) TWA (REL)

0.05

TWA

0.012 0.05 0.05 0.05

TWA TWA TWA TWA

0.05

TWA (TLV)

0.1

TWA

0.05

TWA

0.05 0.05

TWA (TLV) TWA (PEL)

5

Ceiling

0.1 (skc) 0.1 (sk)

TWA TWA

0.1 (sk) 0.3 (sk) 0.075 (sk) 0.05 (sk) 0.02 (sk) 0.06 (sk) 0.1 (sk) 0.075 (sk) 0.23 (sk) 0.05 (sk) 0.1 (sk) 0.1 (sk) 0.075 (sk) 0.1 (sk) 0.1 (sk) 0.3 (sk) 0.05 (sk) 0.1 (sk)

TWA STEL TWA TWA TWA STEL TWA TWA STEL TWA (MAK) STEL (MAK) TWA TWA TWA TWA STEL TWA TWA

Lead chromate (as Pb) Belgium Canada British Columbia China, Hong Kong SAR Malaysia Spain USA ACGIH Lead (II) oxide Finland Lead phosphate (as Pb) Norway USA ACGIH OSHA Lead sulfide China Tetraethyl lead (as Pb) Australia Belgium Canada Alberta British Columbia Quebec China China, Hong Kong SAR Finland Germany Ireland Japan Malaysia Mexico Netherlands New Zealand

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Table 77 (contd) Country/Agency

Exposure limit (mg/m3)

Interpretationa

Norway Poland

0.01 (sk) 0.05 (sk) 0.1 (sk) 0.1 (sk) 0.05 (sk) 0.2 (sk)

TWA TWA STEL TWA TWA STEL

0.1 (sk) 0.075 (sk) 0.075 (sk)

TWA (TLV) TWA (REL) TWA (PEL)

Spain Sweden USA ACGIH NIOSH OSHA

Tetramethyl lead (as Pb) Australia 0.15 (sk) Belgium 0.15 (sk) Canada Alberta 0.15 (sk) 0.5 (sk) Quebec 0.05 (sk) China, Hong Kong SAR 0.15 (sk) Finland 0.075 (sk) 0.23 (sk) Germany 0.05 (sk) 0.1 (sk) Ireland 0.15 (sk) Malaysia 0.15 Mexico 0.15 (sk) 0.5 (sk) Netherlands 0.05 (sk) New Zealand 0.15 (sk) Norway 0.01 (sk) Spain 0.15 (sk) Sweden 0.05 (sk) 0.2 (sk) USA ACGIH 0.15 (sk) NIOSH 0.075 (sk) OSHA 0.075 (sk)

TWA TWA TWA STEL TWA TWA TWA STEL TWA (MAK) STEL (MAK) TWA TWA TWA STEL TWA TWA TWA TWA TWA STEL TWA (TLV) TWA (REL) TWA (PEL)

From ACGIH Worldwide (2003); European Commission (1998); International Lead and Zinc Study Group (2000) ACGIH, American Conference of Governmental Industrial Hygienists; NIOSH, National Institute for Occupational Safety and Health; OSHA, Occupational Safety and Health Administration a TWA, time-weighted average; STEL, short-term exposure limit; MAK, maximum allowable concentration; OES, occupational exposure standard; TLV, threshold limit value; REL, recommended exposure limit; PEL, permissible exposure limit; TRK, technical exposure limit b NOS, not otherwise specified c sk, skin notation Note: For the most current information on these regulations and guidelines, the reader is referred to the relevant regulatory authority.

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Table 78. Regulations and guidelines for maximum lead concentrations in blood in occupational settings Country

MLLa (µg/dL)

Country

Australia

Japan

60

Austria Belgium Canada Czech Republic Denmark

50 (men, and women not capable of reproduction); 20 (women of reproductive capacity) 45–70 80 50–80 50 50–70

Luxembourg Morocco Namibia Netherlands Norway

Finland France

50 70–80

Peru South Africa

Germany

70 (men); 30 (women under 45 years) 70–80

Spain

70 60 80 70 2 µmol/L [41.4 µg/dL] (men) 60 (men) 80 (men); 40 (women) 70

Ireland Israel

70 60 (men); 30 (women of reproductive age)

Thailand United Kingdom

Italy

70

USA

Greece

Sweden

From International Lead and Zinc Study Group (2000) a MLL, maximum lead level

MLLa (µg/dL)

50 (men and women over 50 years); 30 (women under 50 years) 80 60 (men); 50 (adolescents under 18 years); 30 (women of reproductive capacity) 50