52 VOLUME 112 | NUMBER 1 | January 2004 • Environmental Health Perspectives

Children’s Health | Article

It is well recognized that in the past, processing

of lead–zinc and zinc–lead ores in smelters

has resulted in widespread contamination of

the environment and has severely affected the

health of the community, especially young

children. Despite the introduction of emission controls through regulatory guidelines

of, for example, lead in air, mining and smelting operations may continue to contaminate

the environment and humans (Esterman and

Maynard 1998; Hilts 2003; Hunter Health

2003; Morrison 2003a; Van Alphen 1999).

Legal action has been instigated by community members against lead processing companies. Such was the case in a class action

involving some 600 people from Port Pirie,

South Australia (location of the largest lead–zinc

smelter in the world), and North Lake

Macquarie, 120 km north of Sydney, Australia

(Gordon 2002; Pasminco Ltd. 2000a).

Although smelters and/or mines are the

obvious point sources in these communities,

other lead sources may be present and may

contribute to elevated blood lead concentrations, especially in children. For example,

on the basis of total lead concentrations,

Kimbrough et al. (1995) suggested that lead in

paint together with the condition of the house

accounted for 12% of blood lead variance in

children from a community in which a smelter

had closed. Similarly, in the Broken Hill mining community, New South Wales (NSW),

Australia, high-precision lead isotopes demonstrated that paint and gasoline were contributors to blood lead in families, although the

dominant source was lead derived from the

local ore bodies (Gulson 1996; Gulson et al.

1996a, 1996b).

In response to requests for assistance from

members of the North Lake Macquarie community and pediatrician Graham Vimpani, we

have undertaken lead isotopic analyses of environmental and biologic samples, collected over

a decade, to determine the sources of lead,

especially in the teeth of children. In some

cases, the parents were concerned that their

children may have been exposed in utero. In

this article we present the results of these investigations, which illustrate the potential of the

lead isotopic fingerprinting method in determining lead sources in such communities but,

because of funding constraints, are neither

systematic nor exhaustive.

Materials and Methods

Setting/history. The community of North Lake

Macquarie is located approximately 120 km

north of Sydney, NSW, Australia, and consists

of three suburbs (Boolaroo, Argenton, Speers

Point), with approximately 1,600 households.

Three junior schools for pupils 5–12 years old

are located in the area.

A primary zinc–lead smelter, Cockle Creek

Smelter Pty. Ltd., is located within this community (Figure 1) and is currently operated by

Pasminco Ltd. The smelter began production

in 1897, ceased operation in 1922, resumed

again in 1961, and closed in September 2003.

It produces zinc, lead, and sulfuric acid as

major products.

In 1991, an investigation was undertaken

by the Hunter Area Public Health Unit.

This consisted of measurements of blood lead

in children 1–13 years old in Boolaroo and

Argenton, along with measurements of lead

in soil, household dust, and paint. The results

showed that 6% of children 1–4 years old had

blood lead levels > 25 μg/dL and 84% had

blood lead levels > 10 μg/dL (Galvin et al.

1993).

There was a significant relationship

between the higher blood lead levels and

proximity to the smelter, with the exception

of slag (glassy smelter residue) infills (Galvin

et al. 1993; Unpublished data). In addition,

the soil survey (202 samples) reported lead

values ≤ 21,460 ppm in First Street, directly

opposite the smelter, with decreasing values

away from the smelter. Furthermore, there

was widespread use of slag as landfill, mainly

in recreational areas, with levels ≤ 6,000 ppm

Pb as far as 2 km from the smelter and one

value ≤ 15,210 ppm Pb, 1 km from the

smelter (Galvin et al. 1993). Although the

metals in slags are considered to be safely contained within the glassy matrix (e.g., Body et

al. 1988), Morrison (2003b) has shown that

the fine fractions of the Cockle Creek slags

have a very high bioaccessibility.

After disclosure of the results of the

Hunter Area Public Health Unit investigations, a Community Consultative Committee

was formed that later became known as the

Lake Macquarie Environmental Health

Coordination and Liaison Committee.

In 1992, decontamination work was

undertaken at the Boolaroo school. At the same

time, the local government body instituted a

Address correspondence to B.L. Gulson, Graduate

School of the Environment, Macquarie University,

Balaclava Road, Sydney NSW 2109 Australia.

Telephone: 61-2-9850-7983. Fax: 61-2-9850-7972.

E-mail: bgulson@gse.mq.edu.au

We thank M. Korsch for maintaining the mass

spectrometers in peak condition and for software

development; the families who participated in this

study; T. Gordon for her tireless efforts to assist the

families; J. James for supplying samples from house

1; J. Sullivan from Lake Macquarie Council for supplying the 1998 slag samples; E. O’Brien and T.

Gordon for arranging some contacts with families; A.

Morrison for some sample collection, redrawing of

Figure 1, and critical reading of the draft manuscript;

and the EHP reviewers for constructive comments.

The authors declare they have no competing

financial interests.

Received 15 May 2003; accepted 24 September

2003.

Identification of Sources of Lead in Children in a Primary Zinc–Lead 

Smelter Environment

Brian L. Gulson,1,2 Karen J. Mizon,1 Jeff D. Davis,2 Jacqueline M. Palmer,2 and Graham Vimpani3

1Graduate School of the Environment, Macquarie University, Sydney, New South Wales, Australia; 2Commonwealth Scientific and

Industrial Research Organisation/Exploration and Mining, North Ryde, New South Wales, Australia; 3Hunter Area Health Service,

Newcastle, New South Wales, Australia

We compared high-precision lead isotopic ratios in deciduous teeth and environmental samples to

evaluate sources of lead in 10 children from six houses in a primary zinc–lead smelter community at

North Lake Macquarie, New South Wales, Australia. Teeth were sectioned to allow identification

of lead exposure in utero and in early childhood. Blood lead levels in the children ranged from 10 to

42 μg/dL and remained elevated for a number of years. For most children, only a small contribution to tooth lead can be attributed to gasoline and paint sources. In one child with a blood lead

concentration of 19.7 μg/dL, paint could account for about 45% of lead in her blood. Comparison

of isotopic ratios of tooth lead levels with those from vacuum cleaner dust, dust-fall accumulation,

surface wipes, ceiling (attic) dust, and an estimation of the smelter emissions indicates that from

approximately 55 to 100% of lead could be derived from the smelter. For a blood sample from

another child, > 90% of lead could be derived from the smelter. We found varying amounts of

in utero–derived lead in the teeth. Despite the contaminated environment and high blood lead

concentrations in the children, the levels of lead in the teeth are surprisingly low compared with

those measured in children from other lead mining and smelting communities. Key words: children,

environmental samples, isotopes, lead, smelter, teeth. Environ Health Perspect 112:52–60 (2004).

doi:10.1289/ehp.6465 available via http://dx.doi.org/ [Online 25 September 2003]
notation of contaminated land on property

certificates within the Hunter Area Health

Service sampling program, as a way to protect

potential purchasers. This produced anxiety

about property values and compounded concerns about health issues. Pasminco Ltd. purchased houses from residents who lived in

a “buffer zone,” which is the eastern section

of the first two streets in Boolaroo and closest

to the smelter (Figure 1; Lunn and Rothery

2000).

In 1995, a commission of inquiry for environment and planning (CIEP; 1995) was held

in response to an application by Pasminco Ltd.

to upgrade the smelter capacity. An outcome

of this inquiry was 63 conditions of consent

relating to environmental controls. These

included a program to reduce smelter lead pollution exposure, designed to remediate historical sources of lead and dust and to reduce

ongoing ambient lead deposition through

plant improvements. The commission of

inquiry also recommended the establishment

of the North Lake Macquarie Remediation

Management Committee, with $A4.5 million

funding from the NSW Environment

Protection Authority, NSW Health, and

Pasminco Ltd.

In 1996, the Environmental Health

Centre was established at Boolaroo to undertake individual house remediation, blood lead

monitoring, and case management. In 1998, a

2-year strategic plan was developed to include

individual house and zonal remediation, blood

lead monitoring and case management, greening, education, marketing and health promotion, and monitoring of ambient air quality.

The remediation program is directed by the

Environmental Health Centre and supervised

by the NSW Department of Public Works

and Services. The aim of the Environmental

Health Centre was to reduce the blood lead

levels of children in North Lake Macquarie to

the national goal of < 10 μg/dL.

Despite improved emission control by

the company and the intense intervention/

remediation programs, 37% of 87 children

younger than 5 years tested from July 2001 to

June 2002 had blood lead levels of ≥ 10 μg/dL

(Hunter Health 2003).

Sampling. Variable numbers of samples

were taken from six houses (Figure 1). In no

house was it possible to obtain all biologic

and environmental samples. For example,

only two blood samples were taken because,

at the beginning of this study, we thought

that teeth would provide a more satisfactory

history of the lead exposure of the children,

given the success of investigations using teeth

at Broken Hill (Gulson 1996; Gulson and

Wilson 1994). In other houses, most of the

environmental samples were obtained except

for ceiling (attic) dusts. Sampling protocols

generally followed those described by Gulson

et al. (1996c).

Subjects and sampling details. A brief history of the children follows. Where possible,

teeth were also obtained from siblings.

House 1. This family lived in the house for

14 years, approximately 400 m from the

smelter boundary but just outside the buffer

zone. The mother had been raised in a nearby

suburb, and both female siblings were born in

Boolaroo. The younger sibling had a blood lead

level of 31 μg/dL at the time of the first visit to

the pediatrician, and this remained > 25 μg/dL

for more than 2 years despite efforts to clean up

the house and yard. She has progressed poorly

at school and has experienced behavioral

problems. Her sister is 3 years older and had a

blood lead of 24.5 μg/dL at 10 years of age;

she also had some learning problems. The

older brother had a blood lead of 21 μg/dL at

14 years of age. The blood lead of the mother

was 11 μg/dL. The children did not play in

the “dirt,” according to the mother. Sampling

of this house was undertaken by the public

health unit and showed lead levels in the ceiling (attic) dust of 19,000 ppm, soil levels of

1,100 ppm, and vacuum cleaner dust levels of

1,200 ppm.

House 2. The following information is

extracted with permission from the LEAD

[Lead Education and Abatement Design

group] Action News (Mosman 1997), from

Gordon (2002), and from assessors’ reports

Environmental Health Perspectives • VOLUME 112 | NUMBER 1 | January 2004 53

Munibung Hill

(164 m)

Main Northern Rail Line

Argenton

Pasminco

Smelter

1st Street

Boolaroo

7th Street

Speers Pt

Lake Macquarie

1,000 m

Cockle Creek

Main Northern Rail Line

3

5

1 4

2

6

Figure 1. Location of the Cockle Creek smelter in relation to surrounding suburbs and houses sampled

(numbered 1–6). House 7 is located approximately 3 km north of the smelter. Arrow points to north.

Children’s Health | Lead in children from a smelter community
(Waller G. Unpublished data) supplied by the

householder. This house is located approximately 550 m downwind from the smelter

boundary but outside the buffer zone. There

were three children 15, 9, and 3 years old at

the time of sampling in April 1998; the family

had moved into the house from a low-lead

environment in November 1990. The mother

had a blood lead level of 13 μg/dL. The older

daughter was 4 years of age when the family

moved into the house. In 1995 the youngest

girl, at age 3, suffered health problems with

stomach pains, loss of appetite, constipation,

and high temperature. She also experienced respiratory problems and lost the use of her legs. A

bone scan showed possible lead lines, and a

follow-up blood test showed a lead level of

34 μg/dL. An environmental assessment of the

home by a lead assessor showed the following

values: front yard soil, 2,650 ppm Pb; backyard

soil, 1,010 ppm; ceiling dust, 15,800 ppm (lead

loading of 3,160,000 μg/m2 or 3.16 g/m2);

the front bedroom window well where the

child slept had a lead loading of 12,333 μg/m2.

Paintwork throughout the house was in excellent condition, although comprehensive testing for our investigations showed leaded paint

in the lower (older) layers. The house was

remediated in the beginning of 1997 through

the Environmental Health Centre. However,

repeat tests 7 months later by the same assessor

showed that the front wall of the house (facing

the smelter), which had been completely

repainted, had a lead loading of 5,935 μg/m2,

compared with a preremediation level of

2,950 μg/m2. A 12-month follow-up showed

that the remediated ceiling cavity contained

dust with 10,240 ppm Pb (lead loading of

13,820 μg/m2). Samples of ceiling dust were

collected in two areas, one from the open area

of the ceiling and another in a location not easily accessible which contained deposits up to

2 cm thick of a crusted orange dust. Dust fall

accumulation was measured by leaving petri

dishes in the ceiling and frequented locations

in the house for about 3 months. Dust wipes

were also collected in a number of locations,

especially the younger child’s bedroom. For

comparison, a petri dish was placed in the

lounge room of the adjacent neighbor’s house.

Teeth were available from the two girls.

House 3. This house is approximately

1 km north of the smelter in the direction of

the main summer prevailing winds (Galvin

et al. Unpublished data). The front wall of the

house is located approximately 20 m from a

main thoroughfare. The mother, pregnant at

the time, moved into the house in September

1995 from a newly built house in a low-lead

environment, and started to renovate. At

26 weeks of pregnancy, she went into labor,

and the baby lived for 12 hr. She again undertook renovations during her second pregnancy,

the following year. The baby had blood lead

levels of 22 μg/dL at 10 months and 14 μg/dL

at 15 months. The front yard was well grassed

but the soil, assessed by the independent assessor for the Environmental Health Centre, had

a concentration of 82,000 ppm Pb, probably

due to the presence of dispersed slag particles,

clearly present in the samples. Additional soil

samples were collected at the front and rear

yards and under the house. Exterior and interior paint was in reasonable condition. Wipes

were collected from the front walls of the

house, an outer verandah wall, and window

sills of two front windows. The baby’s room

had been renovated, but the remainder of the

house was in a state of disrepair, with gaps

between ceilings and walls in a number of

rooms and carpets in poor condition. Petri

dishes were placed in the dining room, lounge

room, and child’s bedroom. At the time of

sampling in July 1998, the family was not

living in the house.

House 4. The house is located approximately 500 m from the smelter stack. The

mother was raised in a suburb approximately

2 km east of the smelter that was subject to

smelter emissions during her childhood, especially sulfur dioxide. The family moved into

the Boolaroo house in about 1976. The parents carried out a lot of renovations when the

children were very young. The mother’s blood

lead was never measured. The boy spent time

in the back yard moving surface dirt with

his toy trucks. His blood lead was 14 and

15 μg/dL when he was 9 and 10 years old,

respectively. He has major learning and behavioral difficulties and was assessed at one stage

to be 5 years behind in school. His younger

sister had blood lead levels of 6–8 μg/dL. She

played mainly indoors and experienced no

learning or behavioral problems. No environmental or blood samples were collected from

this house, although the public health unit

analyzed a sample of ceiling dust and found it

to contain up to 9,000 ppm Pb.

House 5. This family moved into their

house, located across the street from the

smelter boundary, in 1990. Their former

abode had low lead exposure, but both parents

had grown up in Boolaroo. The mother had

lived in Boolaroo since she was 10 years old;

her blood lead was 17 μg/dL. The female child

was 18 months old when the family moved to

Boolaroo and had a maximum blood lead of

38 μg/dL. The male child was born in 1990,

and his maximum blood lead was 42 μg/dL.

Both children played on the front verandah

facing the smelter, and this was cleaned every

day by the mother. Both children had major

learning difficulties and behavioral problems

and required speech therapy. Environmental

samples measured by a lead assessor showed

that soil in both front and rear yards contained more than 4,000 ppm Pb, ceiling dust

contained about 2,760 ppm, vacuum cleaner

dust 2,650 ppm, and the top of a ceiling fan

10,670 ppm. No environmental or blood samples were available for lead isotope analysis.

House 6. This family lives within approximately 500 m of the smelter boundary and in

the direction of prevailing winds. The blood

lead of both parents was < 10 μg/dL. The girl

had a blood lead of 28 μg/dL at age 4 but

did not appear to have any learning difficulties. The boy had a blood lead of 38 μg/dL at

18 months old and was diagnosed as autistic

at a later stage. He has learning and speech

difficulties. The parents renovated their

house, including removing a false ceiling,

while the mother was pregnant with the son.

To minimize contribution from leaded paint,

the husband replaced the exterior of the house

with new cladding. The house underwent

remediation in 1999. About 18 months after

remediation, the ceiling dust contained

15,800 ppm Pb in the 250 μm fraction

(Morrison A. Personal communication). No

blood samples were available for analysis for

lead isotopes.

House 7. This house is located approximately 3 km north of the smelter. The family

moved into the house in 1992 from a low-lead

environment. The two girls, 6 and 7 years old

at time of exposure, have been diagnosed with

autism. One girl with a blood lead level of

20 μg/dL has pica, and the high blood lead

was attributed to slag present in the soil.

Inspection of several soil samples, especially

those from where the girls played most and

ate dirt, showed the presence of lead paint

flakes and a very complex mixture of other

particles. Lead paint samples from the house,

lead paint grains from the soil, and blood

samples were analyzed.

Analytic methods. Environmental and

blood samples were prepared following the

methods described by Gulson et al. (1996c).

Gulson and Wilson (1994) and Gulson

(1996) demonstrated the use of the lead isotope technique, combined with the well-established histology of teeth, in evaluating in utero

and early childhood lead exposure from slices

of deciduous teeth. In this approach, analysis

of the enamel provides evidence of in utero

exposure. Analysis of dentin provides evidence of exposure during the early childhood

years, when hand-to-mouth activity is usually

an important contributor to lead body burden, and potentially up to the time of tooth

exfoliation.

In children exposed to lead sources from

mining, paint, or gasoline in communities such

as the Broken Hill lead mining community, it

has been shown that the source of lead from

the incisal sections was different from the

source of lead in the cervical sections of deciduous teeth, reflecting the change in lead from

exposure in utero to that in early childhood

(Gulson 1996; Gulson and Wilson 1994).

Children’s Health | Gulson et al.

54 VOLUME 112 | NUMBER 1 | January 2004 • Environmental Health Perspectives
The deciduous teeth were crowns only

because the roots had been resorbed. Wherever

possible, central and/or lateral incisors were

analyzed to allow comparison with other

studies. The crowns of both upper and lower

incisors were cut transversely into slices

1–2 mm thick from the incisal and cervical

areas using a diamond-impregnated stainless

steel disk. The incisal section consisted of

enamel and varying amounts of coronal

dentin. Because enamel and coronal dentin are

formed before the crawling stage of most children (Lunt and Law 1974; Orban 1953), they

provide an indicator for lead exposure in utero

and in earliest childhood. For determinations

on enamel samples, as much attached dentin as

possible was removed, and vice versa. The

lower central portion of the incisal section was

reamed to ensure removal of any later-formed

circumpulpal dentin.

As much as possible of the thin veneer

of enamel was cut from the cervical section

using a dental bur, leaving mainly dentin.

The pulpal canal in the cervical section was

usually resorbed to varying degrees, but

approximately 2 mm of the pulpal canal and

dentin was reamed out, to ensure minimal

contribution from secondary (circumpulpal)

dentin. The dentin in the cervical section provides an integrated exposure to lead from the

time of eruption of the tooth until exfoliation

(Purchase and Fergusson 1986; Rabinowitz

et al. 1989, 1991).

After a rigorous washing procedure

described by Gulson (1996), a 202Pb “spike”

solution of known isotopic composition and

lead concentration was added to the tooth

sample to obtain the concentration of lead

and isotopic composition of the unknown

sample in the one analysis. The methods of

analysis are described in detail by Gulson and

Wilson (1994) and Gulson (1996).

Because of the relatively low lead concentrations observed in the teeth of some of these

children who had high blood lead concentrations over periods extending apparently to

several years, we were concerned that our rigorous tooth “cleaning” procedure with hydrogen peroxide may have removed much of the

lead. To evaluate this, a central incisor was

sliced sagittally (lengthwise) and then in half,

and the enamel/dentin sections prepared as

described above. The tooth sections were then

subjected to a 3-hr peroxide leach, rinsed,

dried, reweighed, and subjected to a further

leach for 21–24 hr. The tooth section was

then cleaned with our normal methods and

analyzed. Leachates were spiked with 202Pb

and analyzed.

Results

Because of the limited number of samples, it

was not possible to rigorously analyze the data

using statistical methods, a condition also

found by Gwiazda and Smith (2000) and

Manton et al. (2000).

Environmental Health Perspectives • VOLUME 112 | NUMBER 1 | January 2004 55

Table 1. Isotopic and lead concentration data for samples from house 1.

Sample type 208Pb:206Pb 207Pb:206Pb 206Pb:204Pb 207Pb:204Pb Pb (ppm) Date collected

Soil, front yard (–100 μm)a

1 2.1516 0.9002 17.25 15.52 3,090 29 Apr 1993

2 2.1560 0.9043 17.15 15.51 4,130 29 Apr 1993

3 2.1555 0.9022 17.22 15.53 4,700 29 Apr 1993

Soil, backyard (–100 μm)a

7 2.1465 0.8965 17.30 15.51 740 29 Apr 1993

8 2.1468 0.8952 17.38 15.56 3,340 29 Apr 1993

Paint, wallb

1 2.1994 0.9366 16.54 15.49 3,820 29 Apr 1993

2 2.1654 0.9140 16.94 15.49 110 29 Apr 1993

Vacuum cleaner, house dust (–100 μm)c

1 2.1435 0.8913 17.62 15.70 3,320 29 Apr 1993

2 2.1385 0.8899 17.50 15.57 3,280 29 Apr 1993

3 2.1385 0.8902 17.51 15.59 3,610 29 Apr 1993

Vacuum cleaner, bedroom 2.1276 0.8790 17.76 15.61 6,960 29 Apr 1993

aSample numbers indicate separate soil sample sites. bSample numbers indicate difference locations on the house. cSample numbers indicate subsamples from a single bag.

Table 2. Isotopic and lead concentration data for samples from houses 2 and 6.

Sample type 208Pb:206Pb 207Pb:206Pb 206Pb:204Pb 207Pb:204Pb Pb (ppm) Date collected

Petri, dust (adjacent neighbor) 2.1511 0.8966 17.38 15.58 1,240 μg/m2

/30 days 17 Jul 1998

Petri, dust 2.1383 0.8893 17.47 15.54 4,780 μg/m2/30 days 17 Jul 1998

Wipe, window sill 2.1481 0.8958 17.35 15.55 510 μg/m2

/30 days 08 Apr 1998

Wipe, ceiling dust 2.1824 0.9204 16.90 15.55 480 μg/m2/30 days 08 Apr 1998

Ceiling, dust crust 2.2153 0.9514 16.19 15.40 780 ppm 08 Apr 1998

Ceiling, dust (neighbor) 2.1438 0.8927 17.43 15.56 15,800 ppm 19 Feb 2003

Table 3. Isotopic and lead concentration data for samples from house 3.

Sample type 208Pb:206Pb 207Pb:206Pb 206Pb:204Pb 207Pb:204Pb Pb Date collected

Blood from baby 2.1478 0.8976 17.32 15.55 13.6 μg/dL 11 Aug 1998

Paint, front housea 2.2102 0.9453 16.35 15.46 NM 17 Jul 1998

Paint, outer sheds attached to housea 2.2196 0.9557 16.10 15.39 NM 17 Jul 1998

Soil, backyard 2.1659 0.9123 16.95 15.47 490 ppm 17 Jul 1998

Soil, front yard 2.1471 0.8968 17.29 15.51 530 ppm 17 Jul 1998

Soil, under house 2.1369 0.8831 17.70 15.63 1270 ppm 17 Jul 1998

Wipe, front veranda wall 2.1320 0.8855 17.55 15.54 980 μg/m2 17 Jul 1998

Wipe, front wall 2.1308 0.8845 17.56 15.53 500 μg/m2 17 Jul 1998

Wipe, front window sill 2.1285 0.8833 17.58 15.52 57,000 μg/m2 17 Jul 1998

Petri, dust from child’s room 2.1340 0.8844 17.63 15.59 505 μg/m2/30 days 22 Sep 1998

Petri, dust from dining room 2.1436 0.8914 17.50 15.60 1,143 μg/m2/30 days 22 Sep 1998

Petri, dust from front room 2.1358 0.8894 17.53 15.59 41,014 μg/m2/30 days 22 Sep 1998

NM, not measured. 

aRapid reaction with lead test.

Children’s Health | Lead in children from a smelter community
The results are presented in Tables 1–5 and

graphically as an isotope ratio plot (Figure 2) of

the type conventionally used in isotope geochemistry and less commonly in environmental

health investigations (e.g., Gulson et al. 1996c;

Rabinowitz and Wetherill 1972).

The superiority of lead isotope analyses

over elemental lead analyses lies in their ability to assign proportions to the contributing

lead sources. The success of this process is

contingent on there being sufficient difference

in the lead isotopic ratios in the source materials and the ability to detect this analytically.

The larger the difference in isotopic composition between the sources, the more definitive

are estimations of source apportionments.

Australia is unique because the isotopic compositions of its main sources of lead come

from deposits that are geologically old

(formed about 1,700–1,800 million years

ago). The 206Pb:204Pb ratio in these deposits is

16.0–16.1; smaller and geologically younger

deposits from the same continent formed

about 400–500 million years ago have a

206Pb:204Pb ratio of about 18.1–18.3 (Gulson

1986). The isotopic contrast between these

two deposit groups is about 100 times our

experimental error for blood samples. In contrast, Manton et al. (2000) stated that in the

United States, where the isotopic differences

between sources are generally much smaller

than in Australia, the lead isotope method

provides satisfactory discrimination in only

one in five cases.

In simple cases where there is two-component mixing of lead (i.e., two main sources or

end members), the isotopic data define linear

trends on plots of isotopic ratios as shown in

Figure 2. For any point X lying on that linear

trend, it is possible to estimate the proportion

of each of the end members (em) or sources

by the following relationship:

Proportion of sample X (%) = 

An example of the calculation is given for the

slag in the following section.

Possible sources of lead and their lead

isotopic fingerprints. Smelter emissions/slag.

An indirect measure of the isotopic composition of smelter emissions can be derived from

the analysis of slag samples. However, slag

samples represent only a limited time interval

because their composition varies in consonance with the feedstock for the smelter.

A slag sample from July 1998 has an isotopic ratio of 17.78 (Table 4, Figure 2), which

shows that the lead in the feedstock at that

206 204 206 204

1

206 204

2

206 204

1

100 Pb Pb Pb Pb

Pb Pb Pb Pb

x em

em em

: –:

: –: ×

Children’s Health | Gulson et al.

56 VOLUME 112 | NUMBER 1 | January 2004 • Environmental Health Perspectives

Table 4. Isotopic data for slag samples collected.

Sample type 208Pb:206Pb 207Pb:206Pb 206Pb:204Pb 207Pb:204Pb Date collected

Slag 1 2.1268 0.8774 17.78 15.60 11 Aug 1998

Slag 2 2.1288 0.8782 17.78 15.61 11 Aug 1998

Table 5. Isotopic and lead concentration for teeth samples.

House Sex Max PbB (age) Tooth type Section 208Pb:206Pb 207Pb:206Pb 206Pb:204Pb 207Pb:204Pb Pb (ppm) Date collected

1 F Lower canine E 2.1674 0.9136 16.96 15.50 2.2 23 Aug 1993

D 2.1613 0.9104 17.02 15.49 13.3 23 Aug 1993

Cent inc E 2.1341 0.8866 17.56 15.57 0.8 23 Aug 1993

D 2.1361 0.8915 17.43 15.54 1.4 23 Aug 1993

1 F 31 (5) Left upper inc E 2.1509 0.9008 17.19 15.48 7.4 09 Feb 1993

D 2.1500 0.8993 17.24 15.50 19.9 09 Feb 1993

2 F 2nd molar ?E 2.1696 0.9176 16.89 15.50 0.5 05 Feb 1998

?D 2.1714 0.9196 16.82 15.47 1.8 05 Feb 1998

2 F 34 (4) Lower cent inc E 2.1678 0.9133 16.96 15.49 3.1 22 Jun 1998

D 2.1691 0.9132 16.93 15.46 6.1 22 Jun 1998

Upper L inc E 2.1670 0.9133 16.95 15.48 2.2 21 Feb 2000

D 2.1568 0.9069 17.06 15.47 2.5 21 Feb 2000

Upper cent inc E 2.1585 0.9081 17.06 15.49 4.3 31 Jan 2000

D 2.1616 0.9103 17.00 15.48 5.7 31 Jan 2000

4 M 15 (10) Upper canine E 2.1537 0.9025 17.19 15.52 0.6 09 Dec 1999

D 2.1381 0.8906 17.43 15.52 5.5 09 Dec 1999

Root 2.1351 0.8889 17.48 15.54 5.6 09 Dec 1999

4 F 8 (10) Upper canine E 2.1542 0.9027 17.19 15.52 0.6 09 Dec 1999

D 2.1387 0.8906 17.45 15.54 3.4 09 Dec 1999

5 F 38 (?) Upper cent inc E 2.1558 0.9040 17.18 15.53 1.5 09 Dec 1999

D 2.1536 0.9031 17.18 15.52 2.2 09 Dec 1999

Upper L inc E-1 2.1525 0.9026 17.16 15.49 2.5 21 Feb 2000

Tooth cut 3-hr leach 2.1172 0.8736 17.80 15.55 2.7 ng 21 Feb 2000

into quarters 21-hr leach 2.1329 0.8857 17.56 15.55 3.8 ng 21 Feb 2000

E-2 2.1500 0.9013 17.19 15.50 3.0 21 Feb 2000

3-hr leach 2.1254 0.8751 17.70 15.48 2.5 ng 21 Feb 2000

21-hr leach 2.1423 0.8903 17.49 15.57 2.2 ng 21 Feb 2000

D-1 2.1452 0.8973 17.25 15.48 4.5 21 Feb 2000

3-hr leach 2.1231 0.8779 17.68 15.52 3 ng 21 Feb 2000

24-hr leach 2.1297 0.8837 17.65 15.60 2.6 ng 21 Feb 2000

D-2 2.1455 0.8972 17.27 15.49 6.0 21 Feb 2000

3-hr leach — — — — 2.8 ng 21 Feb 2000

21-hr leach 2.1209 0.8759 17.81 15.60 1.6 ng 21 Feb 2000

5 M 42 (?) Upper cent inc E 2.1455 0.8972 17.28 15.50 2.3 09 Dec 1999

D 2.1476 0.8986 17.25 15.50 4.6 09 Dec 1999

6 F 28 (4) Lower L inc E 2.1449 0.8960 17.32 15.52 0.8 05 Feb 1998

D 2.1499 0.8998 17.22 15.49 1.5 05 Feb 1998

6 M 38 (1.5) Lower LL inc D 2.1464 0.8972 17.29 15.51 6.7 05 Feb 1998

Lower RL inc E 2.1388 0.8911 17.41 15.51 2.6 05 Feb 1998

D 2.1467 0.8983 17.25 15.49 5.3 05 Feb 1998

Abbreviations: —, data not sufficient quality; cent, central; D, dominantly dentin; E, dominantly enamel; F, female; inc, incisor; L, lateral; LL, left lateral; M, male; Max PbB (age), maximum

blood lead concentration in micrograms per deciliter and age at which it is measured; RL, right lateral. 
Environmental Health Perspectives • VOLUME 112 | NUMBER 1 | January 2004 57

time was derived mainly from geologically

young Australian mineral deposits, such as

those found at Woodlawn and Elura (Cobar

district) in NSW and/or at Tasmanian mines

such as Rosebery, Que River, and Hellyer

(em2). If, as is likely, the geologically old component in the feedstock was from the Broken

Hill and/or Mt. Isa mines (em1), then the

proportion of geologically young lead in the

slag sample can be estimated, using the above

relationship, at about 90%. Before the

exploitation of the Woodlawn and Elura

mines in the mid-1970s, the source of feedstock to the smelter was from mines in the

Broken Hill area (Firkin 1980). Hence, in the

early days of the smelter, the 206Pb:204Pb ratio

of the feedstock, slag, and emissions would

have been closer to 16.0, the 206Pb:204Pb value

for Broken Hill mines.

Since 1969, the range of materials processed

by the Cockle Creek smelter has been widened

to include material from the Broken Hill and

Cobar districts in western NSW and from

Tasmania (Firkin 1980). Given the figures for

raw material mass balance provided in Firkin

(1980) and our unpublished lead isotope data,

it is possible to estimate the isotopic fingerprint for the feedstock for the smelter. This

calculation, probably representative of the

1970s material and later (because smelter feedstocks are varied as little as possible), gives a

206Pb:204Pb ratio of 17.4, a value lying in the

range measured for dust, as described below. A

calculation employing similar methodology

for emissions from the lead–zinc smelter in the

early 1990s at Risdon, Tasmania (also operated by Pasminco Ltd.), using information on

the feedstock provided by the company, has

previously given a consistent result for the isotopic composition of the feedstock and that of

dust in air in a suburb adjacent to the smelter

(Gulson et al. 1996c).

Leaded gasoline. The isotopic fingerprint

for gasoline can be obtained in two ways, from

a direct measure of the lead in gasoline and

from air monitoring. From a comparison of

lead isotopic measurements in gasoline and

high-volume air filters, Chiaradia et al. (1997)

showed that more than 90% of the lead in

Sydney air was derived from gasoline and that

high-volume air filters provide valid information on the gasoline source. Because the gasoline supplies for Newcastle are predominantly

from Sydney, it is valid to use the analyses of

gasoline and air filters (Chiardadia et al. 1997).

Mean values of the isotope ratios in Sydney

high-volume air filters for 1988–1998 show an

overall increase in the 206Pb:204Pb ratio over

time (Figure 2). The line of best fit through

the mean data has a slope that is considerably

lower than the slope for the soils and teeth.

Paint. Because any house in Australia

built before 1970 could contain lead paint

(Environment Australia 1999) and many of

the houses, especially those closest to the

smelter, are more than 50 years old, we

expected that they would contain leaded paint.

A concern was that the paint history may be

very complex because houses from older parts

of Sydney could contain up to 13 different

layers of leaded paint (Gulson et al. 1995).

Because such complexity might mask any

potential use of lead isotopic measurements in

paint at Boolaroo, a systematic study of the

paints in one house (house 2) was undertaken. The isotopic composition of lead-rich

paint samples both from house 2 and from

the other houses has a relatively restricted

range (Figure 2), with 206Pb:204Pb ratios clustering around a value of about 16.0, although

one sample has a value up to 16.5. The isotopic ratios in most paint samples are characteristic of the lead derived from the Broken

Hill mines.

Diet. Although we undertook no dietary

investigation, we have been measuring dietary

intake in various Australian communities for

more than a decade, usually employing a 6-day

duplicate diet approach. We have found that

diet is generally a minor contributor to blood

lead in the Australian context (Gulson et al.

1996c, 1997, 1999) and expect that the same

would apply in a community such as North

Lake Macquarie.

Environmental samples. Soils. There is a

large variation in the isotopic composition for

the soils, with the 206Pb:204Pb ratio ranging

from 16.9 to 17.5 (Figure 2). This variation

probably reflects changes in the feedstock to

the smelter over time from when the feedstock had a lower 206Pb:204Pb ratio, although

in some cases there may be a small contribution from lead paint and/or gasoline. A similar pattern of lower 206Pb:204Pb ratios in soils

compared with house dust and house air was

observed in the area surrounding the Port

Pirie smelter (Gulson et al. 1996c). We concluded that this pattern once again reflected

the early use of predominantly Broken Hill

feedstock (Body et al. 1988) with a 206Pb:204Pb

ratio of 16.0.

Dust. Dust wiped from hard surfaces,

dust fall accumulation from petri dishes, and

vacuum cleaner dust represent current sources

of smelter lead.

Deposition rates can be extremely high.

For example, wipes from the exterior of

house 3 contained 57,000 μg Pb/m2 despite

the cleaning of the exterior of this house by

the owner approximately 3 weeks before the

sampling. Likewise, monthly dust accumulation from the interior of houses located within

800 m of the smelter ranges up to 4,000 μg

Pb/m2/30 days (Table 3). These high values

may be compared with considerably lower values measured in Sydney over a decade, where

the arithmetic mean value of 298 measurements was 83 ± 92 μg Pb/m2/30 days and the

range was 6–1,046 μg Pb/m2/30 days.

Isotopic ratios in the dust accumulations

lie within a relatively restricted range from

17.35 to 17.63 and are considered to represent mainly the emissions from the smelter

during the 1990s. The sample from house 6

contained 15,800 ppm Pb (Table 2) and was

deposited, postremediation, over approximately 18 months from 2000 to 2001. The

206Pb:204Pb ratio of 17.44 lies within the range

for the 1990s data. The dust data, however,

have slightly lower 206Pb:204Pb values than

+

×

+

15.64

15.56

15.48

15.40

15.3215.8 16.2 16.5 16.9 17.3 17.6 18.0

206Pb/204Pb

207Pb/204Pb

■

■

■

■

■

■ ■■■ ■

■■

■

■

■ ■■ ■■

■ ■ ■

+ + +

+

++ ×+ +×

×

×

×

++

×

*

* * *

*

*

*

*

* *

*

*

++

+

◆

■

■

1994

1993, 1995

1988–1989

1996

1998 1997

Blood

Teeth

Soils

Dust

Paint

Slag

Air filters

Smelter (est.)

+

×

*

■

■

■

◆

Analytical precision

Figure 2. Isotope ratio plot for the various environmental and biologic samples, using data from Tables 1–5

and paint samples from house 7. The estimate of the smelter emissions is for the period covering the 1970s,

using information on the feedstock from Firkin (1980). The air filters are from Sydney, containing > 90% lead

from gasoline (Chiaradia et al. 1997). Dust wipes include dust from vacuum cleaner, surface wipes, ceiling

(attic), and dust-fall accumulation over 3 months using petri dishes. The dashed and solid lines are the best

fits through the data for teeth and air filters, respectively. The 95% error ellipse for replicate analyses of

samples and standards is shown in the upper left corner.

Children’s Health | Lead in children from a smelter community
those for the late 1990s slag. These values are

identical with the ratio of 17.4 obtained from

the feedstock figures listed in Firkin (1980)

and are probably representative of the mid- to

late 1970s.

Careful sampling within the ceiling cavities

can also provide important information on

feedstock change over time. For example, in

house 2, inadequate removal of ceiling dust

meant that, in difficult-to-reach areas, “historical” samples could be obtained. This solidified

orange dust had a 206Pb:204Pb ratio of 16.19

(Table 2), reflecting the early feedstock for the

smelter from the Broken Hill mines, whereas

the “current” ceiling dust from this house had

a 206Pb:204Pb ratio of 17.47 (Table 2). During

“explosions” at the smelter, orange clouds of

dust have been described as entering houses

(Mosman 1997).

Teeth. Lead isotopic composition and lead

concentration data for deciduous teeth from

several children are listed in Table 5. The data

for dentin, considered to represent the lead

exposure during early childhood, are plotted in

Figure 2.

Leaching experiments showed that the

unexpectedly low lead concentrations of tooth

lead in most children were not the result of

leaching with peroxide during the cleaning

process. The amount of lead extracted during

the peroxide leach ranged from 1.6 to 3 ng

Pb, < 3% of the total amount of lead present

in the sample of tooth analyzed. Isotopic

ratios of most leachates also showed that negligible amounts of lead are extracted from the

tooth during the wash; the higher 206Pb:204Pb

ratios in the leachates probably derive from

the peroxide, whose 206Pb:204Pb ratio is 18.1.

The patterns for lead concentrations

observed in deciduous teeth from most of these

subjects are much the same as we observed in

earlier studies in mining environments (Gulson

1996; Gulson and Wilson 1994). That is, the

lead concentrations in the enamel, derived predominantly from the mother, can be an order

of magnitude less than in dentin, which reflects

exposure during early childhood. For example,

in siblings from house 4, the lead concentrations were 0.55 and 0.51 ppm in the enamel

and 5.5 and 3.4 ppm in the dentin for the boy

and girl, respectively. The differences in lead

concentrations in the dentin are consistent

with the maximum blood lead concentrations

of 15 μg/dL for the boy and 10 μg/dL for the

girl. In other sibling pairs from house 5 and

house 6, the lead concentrations in dentin are

only about twice those of the enamel despite

their very high maximum blood lead concentrations of 28–42 μg/dL.

Isotopic compositions in enamel and

dentin show no consistent relationships, in

contrast to those from Broken Hill, probably

because of the limited number of samples and

any changes in feedstock to the smelter.

Blood. We analyzed only two blood samples isotopically. In one case (Table 3), the

isotopic results are the same as those in a sample of soil from the front yard (in which slag

grains were present) but lower than the current smelter products, evidenced in the wipes

and petri dust. We estimate that > 90% of the

lead in the blood was derived from current

smelter activities.

In the other case (house 7), where lead

paint flakes were common in the soil and the

child had pica, about 45% of lead in her blood

was estimated to be derived from paint. The

identification of other lead sources is complicated by the complex history of the land and

its past use, perhaps for disposal of industrial

waste (Davis J. Personal communication;

Morrison A. Personal communication). A contribution to lead burden from emissions from

the smelter is unlikely, because Huang and

Gulson (2002) have shown that beyond about

3–4 km from the smelter, in both northerly

and southerly directions, levels of lead in soil

approximates those in background soils.

Discussion

Sources of lead. This limited study illustrates

the complexities involved in trying to establish sources of lead in children in a community centered around a lead industry. Use of

lead concentrations alone would not have

provided answers to indicated sources, given

the patterns of lead paint in the houses, former use of lead in gasoline, and the dominant

presence of the smelter.

The isotopic measurements demonstrate

that the contribution of lead from paint to

tooth and blood lead levels is minor, except

for the child from house 7. Likewise, the contribution to body burden from gasoline lead

is small because of the decreasing use of

leaded gasoline, the relatively low traffic density in this area, location of the houses relative

to any moderately heavy-traffic thoroughfare,

and the difference in slope of the data for the

high-volume air filters representing gasoline

lead (Figure 2).

Thus, the only credible remaining source

is from the smelting activities that have been

carried out for more than 100 years.

Pathways of lead. Besides direct inhalation of the stack emissions, the main pathway

of lead to the children is through ingestion of

soil and dust.

Soil. High concentrations of lead in the

soil can result from stack emissions (Pasminco

Ltd. 2000b), fugitive emissions (Court 2001),

and the use of slag as fill (Galvin et al.

Unpublished data; Morrison 2003b).

The range of lead isotopic ratios shown in

Figure 2 can arise from several factors, including changes in the feedstock, such as varying

mixtures of geologically old lead with low

206Pb:204Pb ratios of about 16.0 and geologically

young ore with 206Pb:204Pb ratios of about

18.1; a contribution from lead paint with low

206Pb:204Pb values; and past use of gasoline. As

argued above, gasoline is a minor contributor

to lead burden in North Lake Macquarie. The

lead paint can be a significant contributor, and

in the case of two households (houses 1 and 7),

lead paint flakes in soil were identified and

analyzed.

Dust. Dust is now recognized as the major

contributor to blood lead. In urban areas, dust

is derived mainly from lead paint (Clark et al.

1985; Jacobs et al. 2002; Lanphear et al. 1999,

2000, 2002) and from former use of leaded

gasoline (Mielke et al. 1997, 1999). In communities with lead activities, the most obvious

source of the dust was from mining or smelting

processes (Bornschein et al. 1985; Gulson et al.

1994, 1996a, 1996b; Hilts 2003; Landrigan

et al. 1975; von Lindern et al. 2003a, 2003b).

In the present study, we used the dust from

a variety of media, including vacuum cleaner

dust, surface wipes, dust fall accumulation in

petri dishes over 3-month periods, and ceiling

dust. These media provide information for dust

accumulation over periods of days in the case

of, say, window ledge wipes (house 2; Tables 2

and 3) to over a period of about 18 months for

ceiling dust accumulation (Table 2).

Considering the 5 years during which the

dust samples were collected and the diversity

of dust types, the isotopic results showed limited variation. If it is conceded that the overwhelming majority of lead in the dust derives

from smelting activities, the relatively small

isotopic range in the dust samples would

imply that the feedstock to the smelter was

relatively constant over this time interval.

Teeth. Most of the isotopic data for tooth

dentin exhibit a shift to the left of the dust data

and overlap the trend for the soils (Figure 2).

This could be interpreted to mean that the

soils were a more significant contributor to

lead in tooth dentin and the dust or that

another lesser source of lead was present, such

as gasoline and/or lead paint. Gasoline lead is

considered a minor contributor to that in the

environment, teeth, and blood in this area.

However, for at least one set of siblings, from

house 4, the isotopic composition in the

dentin is the same as the dust from the neighboring houses.

Using the estimations discussed above for

the isotopic composition of the smelter emissions based on dusts and feedstock materials,

approximately 55–100% of the lead in teeth

could derive from the smelter. This estimation

assumes that paint is the other end member for

the calculation, rather than gasoline.

From this and other studies, we suggest

that if the enamel lead in deciduous teeth is

< 1 ppm and possibly closer to 0.5 ppm, these

low levels reflect a minimal in utero exposure of

the child. For many children from North Lake

Children’s Health | Gulson et al.

58 VOLUME 112 | NUMBER 1 | January 2004 • Environmental Health Perspectives
Environmental Health Perspectives • VOLUME 112 | NUMBER 1 | January 2004 59

Macquarie, it would appear that significant

amounts of lead have been transferred to the

child. Low levels in enamel were observed only

in siblings from house 4, and the similarity in

isotopic composition of enamel and dentin for

both siblings indicates exposure to a similar

source of lead. Despite tooth differences that

can affect lead concentrations based on whole

tooth analyses (Lockeretz 1975; Purchase and

Fergusson 1986; Tvinnereim et al. 2000), the

levels of lead in enamel were generally > 2 ppm

for the North Lake Macquarie children. In subjects where the ratio of lead in dentin:enamel is

2:1, there has been potentially a higher amount

transferred from the mother, and this may

mask the amounts added to dentin during early

childhood.

Except for siblings from house 1—which

may reflect a higher level of exposure (Table 1)

from the mid- to late 1980s and early 1990s

than that of the other families—the lead concentrations in the teeth from the North Lake

Macquarie children were unexpectedly low

given the widespread contamination of the

environment. For comparison, children with

higher exposure in the Broken Hill lead–zinc

mining community have a mean enamel lead

concentration of 3.1 ppm (range, 1.0–8.9)

and a mean dentin lead concentration of

12.9 ppm (range, 3.0–31.5; Gulson 1996).

Children living in the vicinity of a United

Kingdom smelter had whole crown levels of

12.3 ppm (1.4–340) compared with control

levels of 4.7 ppm Pb; these represent a time of

exposure in the mid- to late 1970s (Delves

et al. 1982). The mean whole tooth lead was

6.4 ppm [95% confidence interval (CI),

4.2–10.0] for children living in the area

around a Czech smelter, compared with background levels of 1.5 ppm Pb (Cikrt et al.

1997). This study covered children exposed in

the late 1980s and early 1990s whose mean

blood lead level for the most contaminated

area around the smelter was 15.4 μg/dL

(95% CI, 7.2–33.1 μg/dL). The mean tooth

lead in 262 incisors from 262 children living

around the Port Pirie lead–zinc smelter in

South Australia was 8.6 ± 1.9 μg/g, and the

correlation of tooth and blood lead at age

7 years was 0.78 (p < 0.001; McMichael

et al. 1994).

The source of the enamel lead could be

the increased amounts released from maternal

bones during the last half of pregnancy

(Franklin et al. 1997; Gulson et al. 1998)

and/or from ambient lead. Unfortunately, the

exposure of the mothers is rarely reported,

although in one case (house 5) the mother’s

blood lead was 17 μg/dL, and in two other

cases (houses 1 and 2) the mother’s blood

lead was ≥ 11 μg/dL.

There are several limitations to this study,

the major deficiency being the limited number of blood samples. A better designed study

would require, besides the blood samples,

direct measurements of smelter emissions

from appropriately placed dust accumulation

devices and high-volume air filter samplers,

more wipes including hand wipes of the children, and better information on feedstock

materials. Nevertheless, the results demonstrate that lead isotopes remain the most powerful tool for evaluating sources of lead in the

environment and in humans, and despite

continuing use, there are a limited number of

practitioners using this technique.

REFERENCES

Body PE, Inglis GR, Mulcahy DE. 1988. Lead Contamination in

Port Pirie South Australia. Report No. 101. Adelaide:South

Australian Department of Environment and Planning.

Bornschein RL, Succop P, Dietrich KN, Clark CS, Que Hee S,

Hammond PB. 1985. The influence of social and environmental factors on dust lead, hand lead, and blood lead levels in young children. Environ Res 38:108–118.

Chiaradia M, Gulson BL, James M, Jameson CW, Johnson D.

1997. Identification of secondary lead sources in the air of

an urban environment. Atmos Environ 31:3511–3521.

CIEP. 1995. Proposed Expansion of the Boolaroo, Zinc/Lead

Smelter by Pasminco Metals-Sulphide Ltd.: Boolaroo, City

of Lake Macquarie: Report to the Honourable Craig

Knowles, Minister for Urban Affairs and Planning and

Minister for Housing. Sydney:Commissioners of Inquiry for

Environment and Planning.

Cikrt M, Smerhovsky Z, Blaha K, Nerudova J, Sediva V,

Fornuskova H, et al. 1997. Biological monitoring of child

lead exposure in the Czech Republic. Environ Health

Perspect 105:406–411.

Clark CS, Bornschein RL, Succop P, Que Hee SS, Hammond

PB, Peace B. 1985. Condition and type of housing as an

indicator of potential environmental lead exposure and

pediatric blood lead levels. Environ Res 38:46–53.

Court J. 2001. Environmental audit for year 1999/2000, Pasminco

Cockle Creek Smelter Boolaroo, NSW. Sydney:Department

of Urban Affairs and Planning.

Delves HT, Clayton BE, Carmichael A, Bubear M, Smith M. 1982.

An appraisal of the analytical significance of tooth-lead

measurements as possible indices of environmental exposure of children to lead. Ann Clin Biochem 19:329–337.

Environment Australia. 1999. Lead Alert: The Six Step Guide to

Painting Your Home. Canberra:Commonwealth of

Australia.

Esterman AJ, Maynard EJ. 1998. Changes in airborne lead particulate in Port Pirie, South Australia, 1986–1996. Environ

Res 79:122–132.

Firkin GR. 1980. Lead-zinc smelting at Sulphide Corporation Pty.

Ltd., Cockle Creek, N.S.W. In: Mining and Metallurgical

Practices in Australia (Woodcock JT, ed). Parkville,

Victoria:Australian Institute of Mining and Metallurgy,

241–248.

Franklin CA, Inskip MJ, Baccanale CL, Edwards CM,

Manton WI, Edwards E, et al. 1997. Use of sequentially

administered stable lead isotopes to investigate changes

in blood lead during pregnancy in a nonhuman primate

(Macaca fascicularis). Fundam Appl Toxicol 39:109–119.

Galvin J, Stephenson J, Wlodarczyk J, Loughran R, Waller G.

1993. Living near a lead smelter: an environmental health

risk assessment in Boolaroo and Argenton, New South

Wales. Aust J Public Health 17:373–378.

Gordon T. 2002. Dust storm: lead contamination in Lake

Macquarie. In: Local Heroes (Phillips K, ed). Annandale,

Australia:Pluto Press, 41–64.

Gulson BL. 1986. Lead Isotopes in Mineral Exploration.

Developments in Economic Geology, Vol 23. Amsterdam:

Elsevier.

———. 1996. Tooth analyses of sources and intensity of lead

exposure in children. Environ Health Perspect 104:306–312.

Gulson BL, Davis JJ, Bawden-Smith J. 1995. Paint as a source

of recontamination of houses in urban environments and

its role in maintaining elevated blood leads in children. Sci

Total Environ 164:221–235.

Gulson BL, Howarth D, Mizon KJ, Korsch MJ, Davis JJ. 1994.

The source of lead in humans from Broken Hill mining

community. Environ Geochem Health 16:19–25.

Gulson BL, Mahaffey KR, Jameson CW, Mizon KJ, Korsch MJ,

Cameron MA, et al. 1998. Mobilization of lead from the

skeleton during the postnatal period is larger than during

pregnancy. J Lab Clin Med 131:324–329.

Gulson BL, Mahaffey KR, Jameson CW, Patison N, Law AJ,

Mizon KJ, et al. 1999. Impact of diet on lead in blood and

urine in female adults and relevance to mobilization of lead

from bone stores. Environ Health Perspect 107:257–263.

Gulson BL, Mahaffey KR, Vidal M, Jameson CW, Law AJ,

Mizon KJ, et al. 1997. Dietary lead intakes for mother/child

pairs and relevance to pharmacokinetic models. Environ

Health Perspect 105:1334–1342.

Gulson BL, Mizon KJ, Korsch MJ, Howarth D. 1996a. Importance

of monitoring family members in establishing sources and

pathways of lead in blood. Sci Total Environ 188:173–182.

———. 1996b. Non-orebody sources are significant contributors to blood lead of some children with low to moderate

lead exposure in a major lead mining community. Sci Total

Environ 181:223–230.

Gulson BL, Pisaniello D, McMichael AJ, Mahaffey KR, Luke C,

Mizon KJ, et al. 1996c. Stable lead isotope profiles in

smelter and general urban communities. Comparison of

biological and environmental measures. Environ Geochem

Health 18:147–163.

Gulson B, Wilson D. 1994. History of lead exposure in children

revealed from isotopic analyses of teeth. Arch Environ

Health 49:279–283.

Gwiazda RH, Smith DR. 2000. Lead isotopes as a supplementary

tool in the routine evaluation of household lead hazards.

Environ Health Perspect 108:1091–1097.

Hilts SR. 2003. Effect of smelter emission reductions on children’s blood lead levels. Sci Total Environ 303:51–58.

Huang YJ, Gulson BL. 2002. Selenium in soils, spermatophytes

and bryophytes around a Zn-Pb smelter, New South

Wales, Australia. Sci Total Environ 293:129–141.

Hunter Health. 2003. North Lake Macquarie Blood Lead

Monitoring Service. Summary of Results (July 2001-June

2002). Public Information Paper. Newcastle, Australia:Hunter

Health. February, 1–4.

Jacobs DE, Clickner RP, Zhou JY, Viet SM, Marker DA, Rogers

JW, et al. 2002. The prevalence of lead-based paint hazards

in U.S. housing. Environ Health Perspect 110:599–606.

Kimbrough R, LeVois M, Webb D. 1995. Survey of lead exposure

around a closed lead smelter. Pediatrics 95:550–554.

Landrigan PJ, Gehlbach SH, Rosenblum BF, Shoults JM,

Candelaria RM, Barthel WF, et al. 1975. Epidemic lead

absorption near an ore smelter. The role of particulate

lead. N Engl J Med 292:123–129.

Lanphear BP, Eberly S, Howard CR. 2000. Long-term effect of

dust control on blood lead concentrations [Abstract].

Pediatrics 106:E48.

Lanphear BP, Hornung R, Ho M, Howard CR, Eberly S, Knauf K,

et al. 2002. Environmental lead exposure during early

childhood. J Pediatr 140:40–47.

Lanphear BP, Howard C, Eberly S, Auinger P, Kolassa J,

Weitzman M, et al. 1999. Primary prevention of childhood

lead exposure: a randomized trial of dust control. Pediatrics

103:772–777.

Lockeretz W. 1975. Lead content of deciduous teeth of children

in different environments. Arch Environ Health 30:583–587.

Lunn S, Rothery D. 2000. Lead remediation in North Lake

Macquarie—a community perspective [Abstract].

Presented at Lead Remediation Effectiveness Symposium,

Coeur d’Alene, Idaho, 22–25 May 2000. 

Lunt RC, Law DB. 1974. A review of the chronology of calcification of deciduous teeth. J Am Dent Assoc 89:599–606.

Manton WI, Angle CR, Stanek KL, Reese YR, Kuehnemann TJ.

2000. Acquisition and retention of lead by young children.

Environ Res 82:60–80.

McMichael AJ, Baghurst PA, Vimpani GV, Wigg NR, Robertson

EF, Tong S. 1994. Tooth lead levels and IQ in school-age

children: the Port Pirie Cohort Study. Am J Epidemiol

140:489–499.

Mielke HW, Dugas D, Mielke PW Jr, Smith KS, Gonzales CR.

1997. Associations between soil lead and childhood blood

lead in urban New Orleans and rural Lafourche Parish of

Louisiana. Environ Health Perspect 105:950–954.

Mielke HW, Gonzales CR, Smith MK, Mielke PW. 1999. The urban

environment and children’s health: soils as an integrator of

lead, zinc, and cadmium in New Orleans, Louisiana, U.S.A.

Environ Res 81:117–129.

Morrison AL. 2003a. An assessment of the effectiveness of lead

Children’s Health | Lead in children from a smelter community
Children’s Health | Gulson et al.

60 VOLUME 112 | NUMBER 1 | January 2004 • Environmental Health Perspectives

pollution reduction strategies in North Lake Macquarie,

NSW, Australia. Sci Total Environ 303:125–138.

———. 2003b. Are They Really a Problem? An Examination of

the Chemistry and Oral Bioaccessibility of Base Metal

Smelter Slags in North Lake Macquarie, NSW [MSc

Thesis]. Sydney:Graduate School of the Environment,

Macquarie University.

Mosman R. 1997. Getting a child out of prison. Lead Action

News 1. Sydney:LEAD Group NSW, 6–10.

Orban B. 1953. Oral Histology and Embryology. St. Louis,

MO:Mosby.

Pasminco Ltd. 2000a. Victorian Supreme Court dismisses class

action against Pasminco. Melbourne:Pasminco Ltd.

Available: http://www.pasminco.com.au/index.asp

[accessed 20 December 2000].

———. 2000b. Exploration, Mining, Smelting, Recycling:

Environment Report 2000. Melbourne:Pasminco Ltd.

Purchase NG, Fergusson JE. 1986. Lead in teeth: the influence

of the tooth type and the sample within a tooth on lead levels. Sci Total Environ 52:239–250.

Rabinowitz MB, Bellinger D, Leviton A, Wang JD. 1991. Lead

levels among various deciduous tooth types. Bull Environ

Contam Toxicol 47:602–608.

Rabinowitz MB, Leviton A, Bellinger DC. 1989. Blood lead-tooth

lead relationship among Boston children. Bull Environ

Contam Toxicol 43:485–492.

Rabinowitz MB, Wetherill GW. 1972. Identifying sources of lead

contamination by stable isotope techniques. Environ Sci

Technol 6:705–709.

Tvinnereim HM, Eide R, Riise T. 2000. Heavy metals in human

primary teeth: some factors influencing the metal concentrations. Sci Total Environ 255:21–27.

Van Alphen M. 1999. Atmospheric heavy metal deposition

plumes adjacent to a primary lead-zinc smelter. Sci Total

Environ 236:119–134.

von Lindern I, Spalinger S, Petroysan V, von Braun M. 2003a.

Assessing remedial effectiveness through the blood

lead:soil/dust lead relationship at the Bunker Hill

Superfund Site in the Silver Valley of Idaho. Sci Total

Environ 303:139–170.

von Lindern IH, Spalinger SM, Bero BN, Petrosyan V, von

Braun MC. 2003b. The influence of soil remediation on

lead in house dust. Sci Total Environ 303:59–78.