Environmental Sources Of Lead Research Articles

Lead exposure and source attribution for a mammalian scavenger before and after a culling program

Lead-based ammunition is a significant source of environmental lead and threatens species that scavenge lead-shot carcasses, particularly in areas with intensive shooting. With the impacts of lead on avian scavengers well established, there is increasing focus on the effects of lead on mammalian scavengers. We investigated lead exposure in a morphologically specialized mammalian scavenger, the Tasmanian devil (Sarcophilus harrisii), by analyzing their blood lead levels (BLLs) before and after a marsupial culling program using linear mixed effects models. We compared lead isotope signatures in devil blood to those in the culling ammunition to inform potential source attributions. We sampled 23 devils before culling and 15 after culling, finding no significant difference in mean BLLs pre and post-culling. However, devils captured closer to forestry coupes where culling had occurred had higher BLLs, and a greater proportion of devils displayed elevated BLLs post-culling (33 % compared to 18 % pre-culling). The highest BLL (7.93 μg/dL) was found in a devil post-culling and this individual had lead isotope signatures that matched the ammunition samples analyzed, suggesting the individual was exposed to lead from scavenging on culled carcasses. While 18 % of the devil blood lead samples had isotope signatures consistent with the ammunition samples, most were measurably different, indicating other sources of lead in the landscape. BLLs in our study landscape were similar to published BLLs for wild devils across Tasmania. That said, lead isotope signatures in the blood of individual devils sampled both before and after culling shifted closer to those of ammunition samples post-culling. Our results indicate that while some individual devils may have been exposed to lead from culling, most devils in the landscape did not show evidence of recent exposure. However, even low lead levels can adversely impact wildlife health and immunity, a particular concern for devils, a species endangered by disease.

Assessing Cross-Sectional Association of Uremic Pruritus with Serum Heavy Metal Levels: A Single-Center Study

(1) Background: Uremic pruritus (UP) is a common and taxing symptom in patients on maintenance hemodialysis (MHD). We have previously shown that blood lead levels (BLLs) and blood aluminum levels (BALs) were separately positively associated with UP in MHD patients. We also found that blood cadmium levels (BCLs) were positively associated with all-cause mortality and cardiovascular-related mortality in MHD patients. We wondered whether there is any correlation between BCLs and UP after adjusting for BLLs and BALs. (2) Methods: Patients enrolled in this study were all from three hemodialysis (HD) centers at Chang Gung Memorial Hospital, Lin-Kou Medical Center, including both the Taipei and Taoyuan branches. Correlations between UP and BLLs, BALs, BCLs, and other clinical data were analyzed. (3) Results: Eight hundred and fifty-three patients were recruited. Univariate logistic regressions showed that diabetes mellitus, hepatitis B virus infection, hepatitis C virus infection, HD duration, hemodiafiltration, dialysis clearance of urea, normalized protein catabolic rate, non-anuria, serum albumin levels, log (intact-parathyroid hormone levels), total serum cholesterol levels, serum low-density lipoprotein levels, log (blood aluminum levels), and log (blood lead levels) were associated with UP. Although log BCLs were not significantly associated with UP (p = 0.136) in univariate analysis, we still included log BCLs in multivariate logistic regression to verify their effect on UP given that our aim in this study was to verify associations between serum heavy metals and UP. Multivariate logistic regressions showed that log BLLs (OR: 27.556, 95% CI: 10.912–69.587, p < 0.001) and log BALs (OR: 5.485, 95% CI: 2.985–10.079, p < 0.001) were positively associated with UP. The other logistic regression, which stratified BLLs and BALs into high and low BLLs and BALs, respectively, showed that high BLLs or high BALs (low BLLs and low BALs as reference) (OR: 3.760, 95% CI: 2.554–5.535, p < 0.001) and high BLLs and high BALs combined (low BLLs and low BALs as reference) (OR: 10.838, 95% CI: 5.381–21.828, p < 0.001) were positively correlated with UP. (4) Conclusions: BLLs and BALs were positively correlated with UP. BCLs were not correlated with UP. Clinicians should pay more attention to the environmental sources of lead and aluminum to prevent UP.

Early-life low-level lead exposure alters anxiety-like behavior, voluntary alcohol consumption and AC5 protein content in adult male and female C57BL/6 J mice

Despite efforts to eradicate sources of environmental lead (Pb), children, predominately in lower socioeconomic areas, are still frequently exposed to unsafe levels of Pb from soils, dust, and water. Human studies suggest that Pb exposure is associated with altered drug consumption in adults; however, there is limited research at comparable exposure levels (blood Pb levels <10 μg/dL). To model how early-life, low-level Pb exposure affects alcohol consumption in adulthood, we exposed postnatal day (PND) 21 C57Bl/6 J mice to either 30 ppm or 0 ppm Lead (IV) Acetate in distilled water until PND 42, and testing began in adulthood. We predicted that mice with early-life Pb exposure would exhibit greater anxiety-like behavior and consume more alcohol in a three-week Drinking-in-the-Dark procedure (20% v/v) and a 24-h two-bottle choice procedure (10% v/v). We also predicted that Pb exposure would decrease whole-brain content of Adenylate Cyclase-5 (AC5), a protein linked to anxiety-like behaviors and alcohol drinking. There was no difference in limited-access binge-like consumption between exposure groups; however, Pb-exposed mice displayed higher two-bottle choice alcohol intake and preference. Furthermore, Pb-exposed mice exhibited greater anxiety-like behaviors in experiments conducted before an alcohol drinking history but not after. Finally, Pb-exposed mice exhibited an upregulation of whole-brain AC5 protein content. However, this difference was not found in the nucleus accumbens, dorsomedial or dorsolateral striatum. These findings conclude that early-life Pb exposure alters voluntary alcohol consumption and whole-brain AC5 protein content in adulthood. Future studies are necessary to further understand the mechanism behind how Pb exposure alters alcohol intake.

Use of historical mapping to understand sources of soil-lead contamination: Case study of Santa Ana, CA

This paper investigates the historical sources of soil-lead contamination in Santa Ana, California. Even though dangerous levels of soil-lead have been found in a wide variety of communities across the United States, public health institutions lack clarity on the historical origins of these crises. This study uses geo-spatial data collected through archival research to estimate the impact of two potential sources of lead contamination in the past -- lead-paint and leaded gasoline. It examines, through a combination of statistical and historical methods, the association between lead concentrations in contemporary soil samples and patterns in the evolution of the city's physical features, such as the growth of urbanized areas and the historical flow of traffic. We emphasize the value of historical data collected through archival research for understanding the sources of environmental lead, particularly leaded gasoline, which our study found to be the most likely and most prominent contributor to soil-lead in Santa Ana's environment. This research contributes to environmental-justice advocacy efforts to reframe lead poisoning as a systemic environmental issue and outlines the path forward to community-level remediation strategies.

Assessment of human exposure to environmental sources of lead arising from the lead battery manufacturing and recycling sector in Europe: demonstration of a tiered approach in a case study.

Standard approaches for the assessment of Man via the Environment exposure are designed to be conservative. However, propagating these exposures into health impact assessment might lead to questionable socio-economic costs. The objective of this study was to develop a novel tiered modelling approach to assess human exposure to lead (Pb) via the environment. The approach starts in Tier 1 from EUSES modelling approach, modified with metal specific transfer factors. The generic Tier 2 approach uses the higher tier model GPM for air quality, and dietary exposure modelling based on EFSA's Comprehensive Food Database, in combination with crop specific transfer factors. Tier 3 considers additional site-specific information such as proximity of inhabitants and agricultural activities in relation to industrial sites. This tiered modelling approach was applied to a case study of 50 lead battery manufacturing and recycling sites across Europe. Data sets from general population human biomonitoring studies were used to compare the predicted additional bioburden of Pb resulting from lead battery manufacturing and recycling. The higher tier assessments were able to demonstrate a >20-fold reduction in modelled Pb exposure compared to default assumptions made in Tier 1. Leading to better estimates for socio-economic costs in health impact assessment.

Strong evidence for the continued contribution of lead deposited during the 20th century to the atmospheric environment in London of today

Although leaded gasoline was banned at the end of the last century, lead (Pb) remains significantly enriched in airborne particles in large cities. The remobilization of historical Pb deposited in soils from atmospheric removal has been suggested as an important source providing evidence for the hypothetical long-term persistency of lead, and possibly other pollutants, in the urban environment. Here, we present data on Pb isotopic composition in airborne particles collected in London (2014 to 2018), which provide strong support that lead deposited via gasoline combustion still contributes significantly to the lead burden in present-day London. Lead concentration and isotopic signature of airborne particles collected at a heavily trafficked site did not vary significantly over the last decade, suggesting that sources remained unchanged. Lead isotopic composition of airborne particles matches that of road dust and topsoils and can only be explained with a significant contribution (estimate of 32 ± 10 to 43 ± 9% based on a binary mixing model) of Pb from leaded gasoline. The lead isotopes furthermore suggest significant contributions from nonexhaust traffic emissions, even though isotopic signatures of anthropogenic sources are increasingly overlapping. Lead isotopic composition of airborne particles collected at building height shows a similar signature to that collected at street level, suggesting effective mixing of lead within the urban street canyon. Our results have important implications on the persistence of Pb in urban environments and suggest that atmospheric Pb reached a baseline in London that is difficult to decrease further with present policy measures.

Developmental lead exposure and adult criminal behavior: A 30-year prospective birth cohort study

Using a variety of research designs and measures of lead absorption, numerous studies link childhood lead exposure to a range of cognitive and behavioral deficits, including low IQ, impulsivity, juvenile delinquency, and criminal behavior in adolescence and early adulthood. In this study, we tested the association between multiple measures of blood lead concentration assessed in childhood with criminal behavior in adulthood and across the life-course. Prospective data from the Cincinnati Lead Study (CLS) included blood lead measures quarterly across the first 78 months of life and the number of times a person was arrested across the life-course (from age 18 to 33 years) and in later adulthood (age 27 to 33 years). Childhood blood lead concentration prospectively predicted variation in adult arrests and arrests over the life-course, indicating lead absorption is implicated in the etiology of crime—especially in geographic areas where environmental sources of lead are more prevalent and concentrated. Efforts to decrease lead exposure in both developed and developing countries should be part of a comprehensive strategy to reduce social dislocation and crime.

Risky bismuth: Distinguishing between lead contamination sources in soils

In a broad environmental study in St. Joseph County, Indiana, elemental data from ∼2000 soil samples and ∼800 paint samples were collected with X-ray Fluorescence (XRF) spectroscopy. The observed lead concentrations were compared to other elemental concentrations in these data. A strong correlation between lead and bismuth concentrations was observed in a subset of the soil samples and in nearly all of the paint samples, with lead levels approximately 150 times higher than bismuth. However, some soil samples contained lead with no bismuth present. Since most lead sources likely contain bismuth as an impurity from refining of native lead ore, but leaded gasoline does not contain any bismuth impurities due to the manufacturing process of tetraethyl lead, it may be possible to distinguish environmental lead sources by XRF. To test if leaded gasoline could be the source of lead in the subset of soil samples containing no bismuth, leaded paint samples were analyzed with Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES), which confirmed the presence of bismuth in leaded paint. Aviation gasoline, which contains tetraethyl lead, was also analyzed by ICP-OES to confirm the absence of bismuth in leaded gasoline. This discovery suggests that XRF can be used to rapidly distinguish different legacy lead contamination sources from one another. For low lead concentrations, elemental measurements of bismuth by ICP-OES can be used in environmental forensics to distinguish leaded gasoline contamination from other sources of lead.

Blood and bone lead levels in South Africa's Gyps vultures: Risk to nest-bound chicks and comparison with other avian taxa

Poisoning, including secondary lead poisoning, is cited as the single most important cause of vulture mortalities in Africa. To evaluate the prevalence of lead poisoning among South Africa's Gyps vultures compared to other, non-scavenging birds, we obtained blood and bone samples from Cape (Gyps coprotheres) and White-backed (G. africanus) vultures. We found that 66% of White-backed Vultures (n = 110, including 85 nest-bound chicks sampled at Dronfield Nature Reserve) and 80% of Cape Vultures (n = 15) had blood [Pb] in excess of 10 μg/dL, the upper limit of background exposure. Average blood [Pb] were 15.4 μg/dL and 29.7 μg/dL for White-backed and Cape vultures, respectively. Bone samples revealed that 12% of White-backed Vultures (n = 18) and 9% of Cape Vultures (n = 75) suffered from subclinical to severe clinical lead poisoning upon their deaths. By contrast, none of the 40 blood, bone or liver samples obtained from non-scavenging bird species were found to exceed background exposure levels. Our results suggest that, unlike non-scavenging birds, the scavenging lifestyle of Gyps vultures subjects them to lead poisoning on a regular basis. Had environmental sources of lead (e.g., dust) been the source of the lead poisoning at the White-backed Vulture breeding colony at Dronfield, all the chicks would have displayed similar blood lead concentrations. Instead the values ranged from barely detectable to very high, leading us to conclude that metallic lead fragments regurgitated by parents during feeding are responsible for the elevated lead levels in some of the chicks at this site. We conclude the likely source of these particles to be fragments of lead ammunition embedded in the carcasses of hunted animals. These results add to a growing body of evidence underscoring the threat posed by the use of lead ammunition and its potential role in the declines of vultures and other scavenging taxa.

Locally produced chicken eggs-a source of dietary lead for an Australian community living with an active lead smelter?

The South Australian regional city of Port Pirie has a long history of environmental lead contamination caused by smelting operations that have resulted in elevated blood lead levels in local children. This study examines the potential exposure of children to lead as a result of consuming eggs produced by domestic chickens kept in a lead-contaminated environment. Lead concentrations were measured in eggs, chicken enclosure soil, chicken feed and forage vegetation collected from a domestic site in Port Pirie. Eggs produced in the vicinity of the operating smelter had higher whole-egg lead concentrations (median: 0.09 mg/kg; range: 0.03-0.19 mg/kg) than control eggs (median: 0.002 mg/kg; range: 0.002-0.005 mg/kg). Soil and forage vegetation were identified as potential lead sources for the chickens in this study. The impact of remediating potential lead sources accessed by the chickens was examined and remedial actions were found to be only partly effective with a three-fold reduction in lead concentrations in eggs. Estimated lead intake for a 2-year-old child consuming these eggs indicated that a diet rich in eggs could more than double the child's daily lead exposure from dietary sources. Eggs produced by chickens housed in residential backyards are a readily avoidable additional source of lead exposure for children living in this industrial community, where all environmental lead sources contribute to an unacceptable daily intake.

Erratum to: Tracing environmental lead sources on the Ao mountain of China using lead isotopic composition and biomonitoring

Erratum to: Tracing environmental lead sources on the Ao mountain of China using lead isotopic composition and biomonitoring

Tracing environmental lead sources on the Ao mountain of China using lead isotopic composition and biomonitoring

Atmospheric lead (Pb) and other trace metals can transport over long distance and deposit on remote alpine ecosystems. In this work, the soil profiles, litter and dominant mosses along a large altitude were collected on Ao Mountain, Central China, to obtain the spatial distributions of Pb in these materials, decipher the possible factors controlling the distribution, and quantitatively distinguish the natural versus anthropogenic sources of Pb through the Pb isotopic tracing and biomonitoring. The results show that soil Pb concentrations (mg/kg) decreased significantly with depth, and they were markedly higher in the O (42.6 ± 2.7) and A (36.4 ± 2.2) horizons than in the litter (7.20 ± 1.9) and mosses (28.0 ± 3.9). The Pb enrichment in the surface soils (O and A horizons), litter and mosses existed in the relatively high altitudes, which was attributed to the influences from atmospheric wet deposition, plants, soil physicochemical properties and human activity. The Pb isotopic ratios identified the Pb sources as originating mainly from Chinese coal combustion, mining and smelting. Atmospheric Pb from southeastern, southwestern and northwestern regions could be deposited in the alpine ecosystem by long distance atmospheric transport. The anthropogenic Pb reached over 50% in the O and A horizons, and over 70% in the litter and mosses, which corresponded to the concentrations of 26.9, 17.7, 5.92 and 21.2 mg/kg, respectively. The results indicate that the mutual effects of climate and regional human activity could increase the Pb accumulation in remote alpine ecosystems.

Environmental lead and childhood blood lead levels in US children: NHANES, 1999–2006

ABSTRACTAlthough blood lead levels in the United States have fallen dramatically since 1980, there remain subgroups of children with high blood lead levels. We assessed the relationship between environmental lead sources and blood lead levels in children ages 1 to 5 years from the National Health and Nutrition Examination Survey (NHANES), 1999–2006. Modeled ambient air lead levels and industrial lead releases at the census-tract level were assigned to each child's residence with adjustment for confounding factors. Of 3,223 children, 272 (8.4%) had blood lead levels ≥ 5 ug/dL. Industrial releases (2,252 vs 1,696 lbs/mi2) and ambient air lead levels (2.28 vs 1.75 ng/m3) were greater in exposed versus unexposed children. For every 10,000 lb/mi2 increase in inverse distance squared weighted exposure, there was a 1.13% increase (95% CI: 0.45%, 1.81%) in blood lead (p = .001).

Investigating lead poisoning in children—could surveillance help?

Lead poisoning in children (LPIC) is associated with serious health effects including neurodevelopmental problems. Population-level preventive measures have helped to reduce exposures to new sources of lead for children in high-income countries such as England. However, new LPIC cases can still occur through exposure to existing sources of lead in the environment. In this article, we discuss how development of laboratory surveillance of LPIC could aid investigation and control of environmental sources of lead. Environmental risks are a particular concern for child health due to the higher exposures in comparison to adults and also the potential effects for growth and development. In recognition of this, the World Health Organization European Region (WHO EURO) has developed The Children’s Environment and Health Action Plan for Europe (CEHAPE) to help tackle environment-related child disease among European member states. In addition to tackling morbidity related to air pollution and inadequate sanitation, a key goal of this plan is ‘to reduce the risk of disease and disability arising from exposure to hazardous chemicals (such as heavy metals)’.1 The UK is one of the EURO member states committed to CEHAPE and has a number of pre-existing policies related to environmental risks. However, a need has been identified in the UK to improve knowledge of patterns of poisoning in children and information about the settings in which children are exposed.2 High-income countries such as the UK and USA have been successful in using population-wide measures such as legal restrictions to restrict the use of lead such as drinking water pipes, toys and paint. However, children can still be exposed to environmental lead that had accumulated prior to these interventions. These exposures can be associated with a range of health effects such as headaches, fatigue and abdominal pain. The most recently published evidence for childhood lead …

Environmental and Occupational Risk Factors Effect to Arterial Hypertension: Correlation between Arterial Hypertension and Lead

The main risk factors for hypertension include smoking, the consumption of alcohol, poor dietary habits, lack of exercise, and stress. Scientists have also linked exposure to lead as a risk factor for hypertension. Chemicals are fundamental negative factors for occupational health as they penetrate an organism through the respiratory tract in the state of vapors, gases, dust, and others. There is high correlation between the concentration of chemicals in the environment and time spent of exposure to the chemicals. Some chemicals compounds penetrate through the respiratory tract and irritate the upper respiratory track and lung lobes. They have different influences depending on their solubility. Lead has a harmful effect on organism when it is in higher doses than normal. It exerts an especially harmful effect upon the nervous and circulatory systems. Sources of environmental lead pollution are benzene, coal, paints containing lead, and some working conditions. A population based case controlling model of an analytic study was used. For the study data analysis SPSS 20.0 program were applied single and combined risk factors were accounted by regressive investigation method and results gained were expressed by odds ratio and 95% confidence interval (95% CI) p value. The goal is to assess the correlation of lead to arterial hypertension among miners of the Gobi region provinces. In the sampling we employed a random collection method with collection ratio of 1:2. One hundred miners with hypertension took part in the study. In the control group people without hypertension were assigned and they were of the same age and sex with the experimental group. Among the participants, those of working age had a high prevalence of hypertension and the disease is beginning to affect those of a younger age as well. 82% of those in the experimental group work in hard working conditions and 86% of them work for an average of 11.3 hours in noisy and dusty conditions. The increase of blood-lead content greatly depends on service length. Miners with arterial hypertension who worked for many years had a high content of lead in their blood. Lead content in the air outside of working places has a weak correlation (r = 0.3) with hypertension among those in the experimental group and was statistically significant (p = 0.007). With an increased blood-lead content, a risk for arterial hypertension (AH) increased two times (OR = 2.11 [95% CL; 1.52 - 2.94], p = 0.0001). But lead content in drinking water has an inversely associated with hypertension.

Environmental determinants of different blood lead levels in children: A quantile analysis from a nationwide survey

Blood lead levels (BLLs) have substantially decreased in recent decades in children in France. However, further reducing exposure is a public health goal because there is no clear toxicological threshold. The identification of the environmental determinants of BLLs as well as risk factors associated with high BLLs is important to update prevention strategies. We aimed to estimate the contribution of environmental sources of lead to different BLLs in children in France.We enrolled 484 children aged from 6months to 6years, in a nationwide cross-sectional survey in 2008–2009. We measured lead concentrations in blood and environmental samples (water, soils, household settled dusts, paints, cosmetics and traditional cookware). We performed two models: a multivariate generalized additive model on the geometric mean (GM), and a quantile regression model on the 10th, 25th, 50th, 75th and 90th quantile of BLLs.The GM of BLLs was 13.8μg/L (=1.38μg/dL) (95% confidence intervals (CI): 12.7–14.9) and the 90th quantile was 25.7μg/L (CI: 24.2–29.5). Household and common area dust, tap water, interior paint, ceramic cookware, traditional cosmetics, playground soil and dust, and environmental tobacco smoke were associated with the GM of BLLs. Household dust and tap water made the largest contributions to both the GM and the 90th quantile of BLLs. The concentration of lead in dust was positively correlated with all quantiles of BLLs even at low concentrations. Lead concentrations in tap water above 5μg/L were also positively correlated with the GM, 75th and 90th quantiles of BLLs in children drinking tap water.Preventative actions must target household settled dust and tap water to reduce the BLLs of children in France. The use of traditional cosmetics should be avoided whereas ceramic cookware should be limited to decorative purposes.

Prenatal and postnatal lead exposure and cognitive development of infants followed over the first three years of life: A prospective birth study in the Pearl River Delta region, China

PurposeOur pilot studies showed that there was a significant relationship between low cord blood levels and scores of neonatal behavioral neurological assessment. The study was further to probe the adverse cognitive effects induced by low-level lead exposure during prenatal and postnatal period. MethodTotally 362 mothers with their infants located the PRD, Guangdong, China participated in the study during their stay in these center: 141 in the high lead group [umbilical-cord blood lead levels (UCBLLs)≥3.92μg/dl] and 102 in the low lead group (UCBLLs≤1.89μg/dl). The other 137 subjects failed to complete the study for a variety of reasons. Blood Lead levels (BLLs) were measured by atomic absorption spectrophotometry, equipped with a graphite furnace. The developmental functioning of infants and children was assessed with BSID-II. The children's birth outcome and the rest of information were obtained from their medical records or a comprehensive questionnaire from their parents, which contained demographic characteristics, lifestyle, mother's IQ and environmental lead sources, etc. ResultsOf 380, 243 newborns (63.95%) had complete data collection for all variables included at 6, 12, 24 and 36 months of age. The mean UCBLLs for high and low lead group were 5.63±0.32μg/dl and 1.35±0.26μg/dl, respectively. Significant inverse associations have been found between the UCBLLs and the MDI and the PDI. The associations might attenuate over subsequent years. BLLs at 24 months were significantly associated, in an inverse direction, with MDI at 24 and 36 months. The observed trend of cognitive deficit beginning at 6 months of life might persist, and even develop over the coming years. A positive significant effect of home nurture environment was observed on MDI scores at 12, 24, 36 months of age and PDI scores at 24 and 36 months of age. ConclusionOur study demonstrates that prenatal and postnatal lead exposure as low as 5μg/dl has an adverse effect on neurodevelopment, best arrested by measuring UCBLLs and BLLs at 24 months of age, and suggest a reference for a blood lead critical value below 5μg/dL. The collective evidence indicate that low lead exposure must be addressed appropriately by health policy makers and argues for an improvement of home nurture environment, i.e., reduce the burden of Pb on children and, strengthen the training of cognitive ability.

Geospatial Modeling of Elevated Blood Lead Levels in Children

Background: Low level lead exposure can adversely affect IQ and behavior. Although blood lead levels (BLL) in US children have dramatically declined over the past 40 years with the removal of lead from paint and gasoline, lead used in industrial activities may become part of our outdoor environment and may be a significant contributor to BLL. Methods: Kansas provided geographical coordinates (X,Y), and demographic data on 41,228 children less than 36 months who were tested for BLL between 2000-2005. We investigated the ratio of cases:controls (BLL &gt; 10) on a grid using kernel density. Next we applied a binary regression using a Generalized Additive Model (GAM). The residual spatial variation was modeled by including a smooth spatial function. Lead exposure was estimated as the inverse distance between each residence and the nearest Toxic Release Inventory (TRI) site with lead emissions. Results: Based upon a bandwidth of 0.2, the kernel density (ratio of cases:controls) varies across space. The probability of being a case in each kernel varies from 0.0 to 0.2, depending on geographic location, and was associated with proximity to lead industry, after controlling for the individual-level covariates gender and age and census level covariates poverty and older housing. Conclusions: Findings indicate considerable regional differences in EBLL. Non Residential environmental sources of lead appear to continue to play an important role in the risk of BLL for children.

Identification of environmental lead sources and pathways in a mining and smelting town: Mount Isa, Australia

Lead (Pb) concentrations and isotopic compositions from soils, dusts and aerosols from public land and residential lots adjacent to the copper and Pb mine and smelter at Mount Isa, Australia, were examined to understand the sources and risks of environmental Pb exposure. Urban soil samples contain elevated Pb concentrations (mean 1560 mg/kg), of which 45–85% of the Pb is bioaccessible. The Pb isotopic composition of surface soils (0–2 cm), aerosols and dusts (206Pb/207Pb, 208Pb/207Pb range: 1.049, 2.322–1.069, 2.345) are dominated by Pb derived from the Mount Isa Pb–zinc ore bodies. Underlying soil horizons (10–20 cm) have distinctly different Pb isotopic compositions (206Pb/207Pb, 208Pb/207Pb range: 1.093, 2.354–1.212, 2.495). Surface soil-, dust- and aerosol-Pb are derived predominantly from smelter emissions and fugitive mining sources and not from in situ weathered bedrock. Remediation strategies should target legacy and ongoing sources of environmental Pb to mitigate the problem of Pb exposure at Mount Isa.

Lead exposure assessment from study near a lead-acid battery factory in China

The production of lead-acid battery in China covered about one-third of the world total output and there are more than 2000 lead-acid battery factories. They may cause the major environment lead pollution. Blood lead levels of several hundreds of residents were over 100μg/L due to the waste discharges from a lead-acid battery factory in Heyuan, Guangdong province. This study aimed to find out the environmental lead sources, the human lead exposure pathways, and the amplitudes from a lead-acid battery factory. The study results showed that lead levels in soil, dust, tree leaves and human blood declined with the distances increased from the production site. Twenty nine of 32 participants had blood lead levels of over 100μg/L with an exceptional high value of 639μg/L for one child. This result suggested that the lead-acid battery production from this factory has caused the elevated lead levels in its neighboring environment and residents. Dust intake was the dominant exposure pathway for humans (over 90%). The lead levels found in adult and toddler (6.19 and 50.1μg/kg/d, respectively) in the polluted area were far higher than the provisional tolerable weekly intake (PTWI) of 25μg/kg body weight (translated into 3.5μg/kg/d), which was established by the joint FAO/WHO Expert Committee. Blood lead levels within the family members were strongly correlated with the house dust lead levels. Our results in this study suggested that further studies in this area should be performed to assess human exposure and relevant human health risks from living close to lead-acid battery factories.