Environmental lead exposure in a population of children in northern France: factors affecting lead burden

Tracking the source of contaminant lead in children's blood

Pb isotope ratios are used for apportioning the sources of Pb in the blood of children (ages 1-6) screened for high blood Pb levels (>5 μg/dL) surrounding urban areas of Kansas City, MO. We compared Pb isotope ratios measured in the child's blood with those of the most likely sources of Pb in that child's home environment. The environmental sources sampled consisted of topsoils, paints, occupational sources (e.g., oil rig workers' uniforms, mechanics' clothes), indoor air filters, dusts, and dietary sources (e.g., spices). Blood lead levels (BLL) ranged from 2.9 to 12.7 μg/dL in children from the five homes participating in this study. Measurements of ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb isotope ratios were made by multi-collector ICP-MS. Comparison of the Pb isotope ratios in home environment samples versus those in the child's blood in each home allowed the identification of possible sources of a child's Pb exposure in three homes. In five homes investigated, children's blood Pb levels were most likely to be derived from dusts inside, and topsoil outside, the homes, or a mixture thereof. In one case, blood Pb was derived from turmeric spice and, in another, the Pb was derived from paint. It is not always possible to directly link high BLLs to the environmental sources collected when Pb isotope ratios of the environmental samples did not overlap with those of the blood.

Assessment of trace elements in terminal tap water of Hunan Province, South China, and the potential health risks

A total of 116 terminal tap water (TTW) samples from Xiangjiang, Zijiang, Yuanjiang, and Lishui river basins of Hunan province were collected and concentrations of As, Cd, Cr, Pb, Mn, Zn, Fe, Al, and Cu were determined using inductively coupled plasma mass spectrometry. The results showed that 10% of the water samples exceeded the limit level of Cd established by World Health Organization (WHO) of 0.003 mg L^-1. Three percent of the samples had Fe level and 1% had As level above the WHO limits of 0.3 and 0.01 mg L^-1, respectively. Multivariate statistic approach (cluster analysis and principal component analysis) results revealed that anthropogenic activities and pipeline corrosion were major sources of TTW contamination in Hunan province. The individual and total hazard quotient values estimated by deterministic and probabilistic approaches were both less than 1. However, the mean cancer risk values of Cd were 2.2 × 10^-4 and 1.4 × 10^-4 for Xiangjiang and Yuanjiang river basin, respectively, both greater than 10^-4. The 95th percentile value of cancer risk for Cr was slightly greater than 10^-4 in Xiangjiang river basins. Long-term exposure to Cd and Cr through tap water consumption poses moderate carcinogenic health risks to the local residents.

Human biomonitoring of heavy metals in the vicinity of non-ferrous metal plants in Ath, Belgium

BACKGROUND

A previous study revealed an environmental contamination by heavy metals in the vicinity of two non-ferrous metal plants in Ath, Belgium. The purpose of the current cross-sectional study was to estimate exposure of the population to heavy metals in the vicinity of the plants, in comparison with population living further away.

METHODS

We did a random sampling in the general population of Ath in two areas: a central area, including the plants, and a peripheral area, presumably less exposed. We quantified cadmium, lead, nickel, chromium and cobalt in blood and/or urine of children and adults in three age groups: (i) children aged 2.5 to 6 years (n = 98), (ii) children aged 7 to 11 years (n = 74), and (iii) adults aged 40 to 60 years (n = 106). We also studied subclinical health effects by quantifying retinol-binding protein and microalbuminuria, and by means of a Strengths and Difficulties Questionnaire.

RESULTS

We obtained a participation rate of 24 %. Blood lead levels were significantly higher in young children living in the central area (18.2 μg/l ; 95 % CI: 15.9-20.9) compared to the peripheral area (14.8 μg/l ; 95 % CI: 12.6-17.4). We observed no other significant mean difference in metal concentrations between the two areas. In the whole population, blood lead levels were higher in men (31.7 μg/l ; 95 % CI: 27.9-36.1) than in women (21.4 μg/l ; 95 % CI: 18.1-25.3). Urine cadmium levels were 0.06 μg/g creatinine (95 % CI: 0.05-0.07), 0.21 μg/g creatinine (95 % CI: 0.17-0.27), and 0.25 μg/g creatinine (95 % CI: 0.20-0.30) for children, men, and women, respectively.

CONCLUSIONS

Despite higher blood lead levels in young children living close to the plants, observed metal concentrations remain in the range found in other similar biomonitoring studies in the general population and are below the levels of concern for public health.

Lead concentration in the blood of the general population living near a lead-zinc mine site, Nigeria: Exposure pathways

Lead (Pb) poisoning in children is a major public health catastrophe worldwide. This report summarises both exposure pathways and blood Pb levels in children below 7 years of age and adults (above 18 years) from the Adudu community living near a lead-zinc mine in Nasawara, Nigeria. The average and median blood Pb levels in children and adults were 2.1 and 1.3 μg/dL, 3.1 and 1.8 μg/dL, respectively. However, Pb in 14% of adults' blood exceeded 5 μg/dL, which is the recommended threshold blood Pb concentration in adults as established by the Centers for Disease Control and Prevention (CDC). Furthermore 68% of adults' blood exceeded blood Pb action level of 2 μg/dL. For children, 11.4% and 31% of the blood samples exceeded 5 μg/dL and 2 μg/dL, respectively, while no safe blood Pb level in children has been recommended. In Nasawara, a significant difference (p<0.05) was observed between the various age groups in children with 2-4 years old having the highest levels and 6 year old children having the lowest Pb levels. Although this study did not detect elevated levels of Pb in children's blood in regions such as Zamfara, Nigeria and Kabwe, Zambia, a high percentage of samples exceeded 2 μg/dL. Soils, floor dusts, water and crops also reveal that Pb contamination in the study area could potentially be the major cause of blood Pb in the community exposed to mining. This study also observed a significant correlation between water Pb levels of adults and blood Pb levels, suggesting that water is the major exposure pathway. This analysis highlights the need to properly manage mining activities so that the health of communities living in the vicinity of a Pb-Zn mine is not compromised.

Autism spectrum disorder prevalence and proximity to industrial facilities releasing arsenic, lead or mercury

Prenatal and perinatal exposures to air pollutants have been shown to adversely affect birth outcomes in offspring and may contribute to prevalence of autism spectrum disorder (ASD). For this ecologic study, we evaluated the association between ASD prevalence, at the census tract level, and proximity of tract centroids to the closest industrial facilities releasing arsenic, lead or mercury during the 1990s. We used 2000 to 2008 surveillance data from five sites of the Autism and Developmental Disabilities Monitoring (ADDM) network and 2000 census data to estimate prevalence. Multi-level negative binomial regression models were used to test associations between ASD prevalence and proximity to industrial facilities in existence from 1991 to 1999 according to the US Environmental Protection Agency Toxics Release Inventory (USEPA-TRI). Data for 2489 census tracts showed that after adjustment for demographic and socio-economic area-based characteristics, ASD prevalence was higher in census tracts located in the closest 10th percentile compared of distance to those in the furthest 50th percentile (adjusted RR=1.27, 95% CI: (1.00, 1.61), P=0.049). The findings observed in this study are suggestive of the association between urban residential proximity to industrial facilities emitting air pollutants and higher ASD prevalence.

Blood lead, cadmium and mercury among children from urban, industrial and rural areas of Fez Boulemane Region (Morocco): relevant factors and early renal effects

OBJECTIVES

To describe blood lead (Pb-B), cadmium (Cd-B) and mercury (Hg-B) levels in children living in urban, industrial and rural areas in Fez city (north of Morocco) and to identify the determinants and some renal effects of exposure.

MATERIAL AND METHODS

The study was conducted from June 2007 to January 2008 in 209 school children (113 girls, 96 boys), aged 6-12 years, from urban, industrial and rural areas in Fez city. Interview and questionnaires data were obtained. Blood and urinary samples were analyzed.

RESULTS

The mean of blood lead levels (Pb-B) in our population was 55.53 μg/l (range: 7.5-231.1 μg/l). Children from the urban area had higher blood lead levels (BLLs) mean (82.36 μg/l) than children from industrial and rural areas (48.23 and 35.99 μg/l, respectively); with no significant difference between boys and girls. BLLs were associated with traffic intensity, passive smoking and infancy in the urban area. The mean of blood cadmium levels (BCLs) was 0.22 μg/l (range: 0.06-0.68 μg/l), with no difference between various areas. Rural boys had higher BCLs mean than rural girls, but no gender influence was noticed in the other areas. BCLs were associated with the number of cigarettes smoked at children's homes. The blood mercury levels (BMLs) mean was 0.49 μg/l (range: 0.01-5.31 μg/l). The BMLs mean was higher in urban and industrial areas than in the rural area with no gender-related difference. BMLs were associated with amalgam fillings and infancy in the urban area. About 8% of the children had BLLs ≥ 100 μg/l particularly in the urban area, microalbuminuria and a decrease in height were noticed in girls from the inner city of Fez and that can be related to high BLLs (89.45 μg/l).

CONCLUSIONS

There is a need to control and regulate potential sources of contamination by these trace elements in children; particularly for lead.

Assessment of potential health risk for inhabitants living near a former lead smelter. Part 1: metal concentrations in soils, agricultural crops, and homegrown vegetables

Soil contamination by metals engenders important environmental and health problems in northern France where a smelter (Metaleurop Nord) was in activity for more than a century. This study aims to look at the long-term effects of the smelter after its closedown by combining data on the degree of soil contamination and the quality of the crops grown (agricultural crops and homegrown vegetables) in these soils for a better assessment of the local population's exposure to Cd, Pb, and Zn. Seven years after the Metaleurop Nord closedown, (1) the agricultural and urban topsoils were strongly contaminated by Cd, Pb, and Zn; (2) the kitchen garden topsoils were even more polluted than the agricultural soils, with great variability in metal concentrations within the gardens studied; (3) a high proportion of the agricultural crops for foodstuffs did not conform with the European legislation; (4) for feedstuffs, most samples did not exceed the Cd and Pb legislation limits, indicating that feedstuffs may be an opportunity for most agricultural produce; and (5) a high proportion of the vegetables produced in the kitchen gardens did not conform with the European foodstuff legislation. The high contamination level of the soils studied continues to be a risk for the environment and the population's health. A further investigation (part 2) assesses the associated potential health risk for local inhabitants through consumption of homegrown vegetables and ingestion of soil particles by estimating the site-specific human health assessment criteria for Cd and Pb.

Human biomonitoring on heavy metals in Ath: methodological aspects

The municipality of Ath is characterised by the presence, in its center, of two non-ferrous metal industries whose emissions make local residents concerned for their health. Therefore, authorities of the Walloon Region and the municipality of Ath undertook biomonitoring to assess the impact of those industrial emissions on heavy metal body burden in humans.

This paper describes the study design and methodology used to carry out this human biomonitoring.

A random sampling was done in the general population, in two areas of Ath: an area centered around the industries and a peripheral area. The target population was children (2.5-11 years) and adults (40-60 years) without occupational exposure. The three-stage sampling procedure consisted of a mixture of both mail and telephone recruitment. Firstly, 3259 eligible people, identified from a population register, were mailed an introductory letter. In a second stage, eligible individuals were contacted by phone to propose them to participate in the study. They were randomly contacted until the required sample size was obtained. In the third stage, a second mail was sent to those who agreed to participate with a questionnaire to be filled out. Finally, biological samples (blood and urine) from 278 persons were collected. The final participation rate of this study was 24%.

This sampling procedure, especially designed for the purpose of this biomonitoring study in Ath, allowed us to recruit a sample representative of the population of children and adults of Ath, reaching the expected sample size in a short period of time.

Cd, Pb and Zn oral bioaccessibility of urban soils contaminated in the past by atmospheric emissions from two lead and zinc smelters

Ingestion of dust or soil particles could pose a potential health risk due to long-term metal trace element (MTE) exposure. Twenty-seven urban topsoil samples (kitchen garden and lawn) were collected and analyzed for Cd, Pb and Zn using the unified Bioaccessibility Research Group of Europe (BARGE) method (UBM) test to estimate the human bioaccessibility of these elements. The quantities of Cd, Pb and Zn extracted from soils indicated, on average, 68, 62 and 47% bioaccessibility, respectively, in the gastric phase and 31, 32 and 23% bioaccessibility, respectively, in the gastro-intestinal phase. Significant positive correlations were observed between concentrations extracted with UBM and total MTE contents. Stepwise multiple regression analysis showed that human bioaccessibility was also affected by some physico-chemical soil parameters (i.e. total nitrogen, carbonates, clay contents and pH). The unified test presents some valuable data for risk assessment. Indeed, the incorporation of oral bioaccessible concentrations into risk estimations could give more realistic information for health risk assessment.

Blood lead levels in children of Lucknow, India

After implementing measures to control lead pollution in many countries, blood lead levels (BLLs) in children have been declined. The phase-out of leaded petrol began in Lucknow, the capital of most populated state, Uttar Pradesh in India on April 1, 2000. We evaluated the mean BLL and associated risk factors for lead exposure in Lucknow children (3-12 years) after petrol lead phase-out activity. The mean BLL of the 200 children was 9.3 microg/dL (range: 1.0-27.9 microg/dL). Seventy-four children (37%) had BLL above the Centre for Disease Control and Prevention's (CDC) level of concern (10 microg/dL). When these data were compared with BLLs determined by the George Foundation among the children of Mumbai, Bangalore, Kolkata, Chennai, Hyderabad, and Delhi during the year 1997 when leaded petrol was in use, where 62%, 62%, 87%, 96%, 43%, and 95%, respectively, then exceeded the CDC intervention level. Further, BLL of present study was very close to Mumbai children (age < or =12 years) estimated following the introduction of unleaded petrol, and 33% children had BLL above the CDC concern level with an average 8.4 microg/dL. Low socioeconomic status, proximity of home to traffic density, and mother's illiteracy were the factors associated with elevated BLLs in Lucknow children (P < 0.05). Overall, results indicate a declining trend of BLL in Lucknow children when compared with those reported from other cities of India when leaded petrol was in practice. A national population-based study is recommended to determine the prevalence of elevated BLLs after the phase-out of leaded-petrol. In addition, future studies on other sources of lead exposure in Lucknow are warranted for public health purposes.

Geographical patterns in blood lead in relation to industrial emissions and traffic in Swedish children, 1978-2007

Background

Blood lead concentrations (B-Pb) were measured in 3 879 Swedish school children during the period 1978–2007. The objective was to study the effect of the proximity to lead sources based on the children's home and school location.

Methods

The children's home address and school location were geocoded and their proximity to a lead smelter and major roads was calculated using geographical information system (GIS) software. All the statistical analyses were carried out using means of generalized log-linear modelling, with natural-logarithm-transformed B-Pb, adjusted for sex, school year, lead-exposing hobby, country of birth and, in the periods 1988–1994 and 1995–2007, parents' smoking habits.

Results

The GIS analysis revealed that although the emission from the smelter and children's B-Pb levels had decreased considerably since 1978, proximity to the lead smelter continued to affect levels of B-Pb, even in recent years (geometric mean: near smelter: 22.90 μg/l; far from smelter 19.75 μg/l; p = 0.001). The analysis also revealed that proximity to major roads noticeably affected the children's B-Pb levels during the period 1978–1987 (geometric mean near major roads: 44.26 μg/l; far from roads: 38.32 μg/l; p = 0.056), due to the considerable amount of lead in petrol. This effect was, however, not visible after 1987 due to prohibition of lead in petrol.

Conclusion

The results show that proximity to the lead smelter still has an impact on the children's B-Pb levels. This is alarming since it could imply that living or working in the vicinity of a former lead source could pose a threat years after reduction of the emission. The analysis also revealed that urban children exposed to lead from traffic were only affected during the early period, when there were considerable amounts of lead in petrol, and that the prohibition of lead in petrol in later years led to reduced levels of lead in the blood of urban children.

Impact of a smelter closedown on metal contents of wheat cultivated in the neighbourhood

BACKGROUND

The contamination of soils by heavy metals engenders important environmental and sanitary problems in Northern France where a smelter has been located for more than one hundred of years. It has been one of the most important Pb production sites in Europe until its closedown in March 2003. Ore smelting process generated considerable atmospheric emissions of dust. Despite an active environmental strategy, these emissions were still significant in 2002 with up to 17 tonnes of Pb, 32 tonnes of Zn and 1 tonne of Cd. Over the years, the generated deposits have led to an important contamination of the surrounding soils. Previous studies have shown pollutant transfers to plants, which can induce a risk for human and animal health. The objective of this study was to evaluate the consequences of the smelter closedown on the Cd and Pb contents of wheat (grain and straw) cultivated in the area.

METHODS

Paired topsoil and vegetable samples were taken at harvest time at various distances to the smelter. The sample sites were chosen in order to represent a large range of soil metal contamination. Sampling was realised on several wheat harvests between 1997 and 2003. 25 samples were collected before the smelter closedown and 15 after. All ears of about 1 m long of two rows were manually picked and threshed in the lab. Similarly, straw was harvested at the same time. Total metal contents in soil and wheat samples were quantified.

RESULTS

A negative correlation between metal concentrations in soil and the distance to the smelter was shown. The wheat grain and straw showed significant Cd and Pb contents. The straw had higher metal contents than the grain. During the smelter activity, the grain contents were up to 0.8 mg kg(-1) DM of Cd and 8 mg kg(-1) DM of Pb. For the straw, maximum contents were 5 mg kg(-1) DM of Cd and 114 mg kg(-1) DM of Pb. After the smelter closedown, we observed a very large decrease of Pb in the grain (82%) and in the straw (91%). A smaller decrease was observed for Cd in grain. Despite this improvement, 80% of the studied samples remained non-acceptable for human consumption, according to the European legislation values, due to a high Cd content.

DISCUSSION

Results highlighted a difference in metal accumulation in the plant organs as well as a difference in metal uptake. The approach pointed out the importance of atmospheric fallout in the wheat contamination pathways for Pb. The smelter closedown has lead to a decrease of the Pb content in wheat. It is interesting to relate this finding with the lead blood levels in children living close to the smelter.

CONCLUSIONS

Those results have confirmed the importance of dust fallout in the plant contamination pathways. Before the closedown, Pb measured in the plant was principally originating from the smelter dust emissions. It raised the question of the sanitary risks for humans and animals living in the surrounding a of the smelter.

RECOMMENDATIONS AND PERSPECTIVES

In the literature, very few articles take the dust deposit as contamination pathways for crops into consideration. However, in highly contaminated sites, this pathway can be very important. Thus, it would be worthy studying the uptake of metal contaminants by plants through the foliar system.

Lead exposure in an urban community: investigation of risk factors and assessment of the impact of lead abatement measures

INTRODUCTION

A battery recycling plant located in an urbanized area contaminated the environment with lead oxides. The Secretary of Environment of the State of São Paulo demanded an evaluation of lead exposure among the population in the vicinity of the plant.

OBJECTIVES

To assess the lead exposure of children, to propose control measures and evaluate the impact of these measures.

METHODS

Cross-sectional study of all children<13 years old in a radius of 1km from the plant responsible for the contamination. Blood lead levels (BLL) were determined for each child and questionnaires were applied to their parents. Mean BLL were compared before and after control measures were implemented. Logistic regression identified risk factors of lead exposure.

RESULTS

Of the 850 investigated children, 311 presented BLL above the action limit established by the World Health Organization. Overall, the median BLL was 7.3 micro g/dL and it varied according to age of children (higher among 1-5 years old) and distance of the residence from the plant. Risk factors identified for BLL>10 micro g/dL were: to live in unpaved areas, parent working in the plant, distance from the plant, to play on the ground, pica, and to drink locally produced milk. After control measures were implemented (closing the plant, soil removal, dust vacuum-cleaning in the households, etc.), a reduction of 46% in BLL was observed considering the 241 re-evaluated children with levels >10 micro g/dL.

CONCLUSIONS

This study showed that combined abatement measures were effective in reducing BLL in children living close to a contaminating source. These results informed the decision-making process regarding management of contaminated areas in Brazil.

Occupational and environmental human lead exposure in Brazil

The purpose of this paper is to present a review of data on assessment of exposure and adverse effects due to environmental and occupational lead exposure in Brazil. Epidemiological investigations on children lead exposure around industrial and mining areas have shown that lead contamination is an actual source of concern. Lead in gasoline has been phasing out since the 1980s, and it is now completely discontinued. The last lead mining and lead refining plant was closed in 1995, leaving residual environmental lead contamination which has recently been investigated using a multidisciplinary approach. Moreover, there are hundreds of small battery recycling plants and secondary smelting facilities all over the country, which produce focal urban areas of lead contamination. Current regulatory limits for workplace lead exposure have shown to be inadequate as safety limits according to a few studies carried out lately.

Specific factors for prenatal lead exposure in the border area of China

The objectives of this study are to examine the prevalence of increased blood lead concentrations in mothers and their umbilical cords, and to identify risk factors for prenatal lead exposure in Kunming city, Yunnan province, China. The study was conducted at two obstetrics departments, and 100 peripartum women were enrolled. The mean blood lead concentrations of the mothers and the umbilical cords were 67.3microg/l and 53.1microg/l, respectively. In multiple linear regression analysis, maternal occupational exposure, maternal consumption of homemade dehydrated vegetables and maternal habitation period in Kunming city were significantly associated with an increase of umbilical cord blood lead concentration. In addition, logistic regression analysis was used to assess the association of umbilical cord blood lead concentrations that possibly have adverse effects on brain development of newborns with each potential risk factor. Maternal frequent use of tableware with color patterns inside was significantly associated with higher cord blood lead concentration in addition to the three items in the multiple linear regression analysis. These points should be considered as specific recommendations for maternal and fetal lead exposure in this city.

Renal and neurologic effects of cadmium, lead, mercury, and arsenic in children: evidence of early effects and multiple interactions at environmental exposure levels

Lead, cadmium, mercury, and arsenic are common environmental pollutants in industrialized countries, but their combined impact on children's health is little known. We studied their effects on two main targets, the renal and dopaminergic systems, in > 800 children during a cross-sectional European survey. Control and exposed children were recruited from those living around historical nonferrous smelters in France, the Czech Republic, and Poland. Children provided blood and urine samples for the determination of the metals and sensitive renal or neurologic biomarkers. Serum concentrations of creatinine, cystatin C, and beta2-microglobulin were negatively correlated with blood lead levels (PbB), suggesting an early renal hyperfiltration that averaged 7% in the upper quartile of PbB levels (> 55 microg/L; mean, 78.4 microg/L). The urinary excretion of retinol-binding protein, Clara cell protein, and N-acetyl-beta-d-glucosaminidase was associated mainly with cadmium levels in blood or urine and with urinary mercury. All four metals influenced the dopaminergic markers serum prolactin and urinary homovanillic acid, with complex interactions brought to light. Heavy metals polluting the environment can cause subtle effects on children's renal and dopaminergic systems without clear evidence of a threshold, which reinforces the need to control and regulate potential sources of contamination by heavy metals. Key words: arsenic, biomarkers, cadmium, dopaminergic, heavy metals, interactions, lead, mercury, renal.

Environmental contamination and human exposure to lead in Brazil

Adverse effects caused by environmental lead pollution are well recognized. Being a widespread agent in the environment and a major harmful element to organic systems, mostly to children, lead has been investigated all over the world, aiming to improve measures regarding its control. The purpose of this chapter is to present a review of the situation of production, uses, assessment of exposure, and adverse effects from environmental lead contamination in Brazil. It also presents aspects of Brazilian legislation setting up maximum permissible levels of lead in several environmental compartments such as surface and drinking water, soils, sediment, urban air, and also in commercially sold food, vegetables, fish, and meat, in an effort to control industrial emissions. Epidemiological investigations on children's lead exposure around industrial and mining areas are revised, showing that many situations where lead contamination is potentially present still need to be addressed by governmental agencies. In Brazil, lead was withdrawn from gasoline by the end of the 1980s, and the last lead mining and primary smelting plant was closed in 1995, leaving residual environmental lead contamination, which has recently been investigated using a multidisciplinary approach. Nevertheless, there are hundreds of small secondary battery recycling plants all over the country, running smelting facilities that produce local urban areas of lead contamination.

Assessment of lead exposure and associated risk factors in urban children in Silesia, Poland

A program of childhood lead poisoning prevention was conducted in six cities of Silesia, the most industrialized region of Poland. We analyzed records of 11,877 children aged 24-84 months, tested between 1993 and 1998, to assess children's exposure to lead and associations of blood lead levels (BLL) with season of sampling, questionnaire data, and environmental levels of lead. Air lead concentrations and lead fallout, as measured in the ambient air monitoring system, were below current Polish air quality standards and gradually decreased. The geometric mean (GM) BLL was 6.3 microg/dL (range from 0.6 to 48 microg/dL), and >13% of children had BLL > or =10 microg/dL. Mean BLL declined from 6.8 microg/dL in 1993-1994 to almost 5.5 microg/dL in 1998. GM BLL in spring and summer ('nonheating' season) months were 10% higher than BLL in children tested in fall and winter ('heating' season), although air lead concentrations were lower in nonheating and higher in the heating season. For both the heating and nonheating seasons, there was a significant increase in the mean BLL with increasing air lead concentrations. Poor housing (odds ratio (OR): 1.82; 95% CI: 1.4, 2.3), two or more siblings in the family (OR: 3.12; 95% CI: 2.6, 3.7), lack of recreational trips outside the region (OR: 1.66; 95% CI: 1.47, 1.89), and the time child spent outdoors were associated with elevated BLL. Variables found to affect BLL in the Silesian children should be used to propose criteria to improve identification of children at risk and to focus prevention activities more effectively.

Biomarkers of renal effects in children and adults with low environmental exposure to heavy metals

The health effects of chronic exposure to heavy metals such as lead, cadmium, and mercury are widely documented, yet few data exist about the renal impact of low environmental exposure to these metals, particularly in children. The aim of this study was to assess renal parameters in children and adults living in an environment known for its past heavy metal contamination around two nonferrous smelters in northern France (Noyelles-Godault and Auby) and to compare their results with age and gender-matched controls living in neighboring municipalities with unpolluted soil (total: 400 children, 600 adults, sex ratio = 1). The integrity of renal function was assessed by measuring the urinary excretion levels of total protein, albumin, transferrin, beta(2)-microglobulin, retinol-binding protein, brush border antigen, and the enzyme N-acetyl-beta-D-glucosaminidase (NAG). The mean blood concentrations of lead (Pb-B, children </=42.2 micro/L, adults </=71.3. micro/L) and of cadmium (Cd-B, children </=0.52 microg/L, adults 0.86 microg/L) were all relatively low, indicating a low uptake of these heavy metals from the environment despite relatively high levels in soil (between 100 and 1700 ppm for lead and 0.7 to 233 ppm for cadmium). Pb-B levels were, however, significantly increased in boys, girls, and women--but not men--living in the polluted area. Boys, men, and women living in the polluted area had also on average higher Cd-B levels. The concentrations of mercury in urine (Hg-U) were by contrast similar in control and exposed groups. None of the renal parameters studied showed a significant difference between control and exposed groups. The influence of heavy metals on renal parameters was further assessed by stepwise multiple regression, testing Pb-B, Cd-B, Hg-U, age, gender, body mass index (BMI), urinary creatinine levels, and area of residence as predictors in both children and adults, including first-order metal interaction terms, smoking habits, and alcohol consumption in adults. The only positive correlation was found between the urinary excretion of NAG activity (standardized for BMI and urinary creatinine) and Cd-B levels when taking the whole children population, indicating that even low cadmium burdens may produce subtle effects on the proximal tubule in children, although deleterious consequences are unlikely should exposure not increase. However, in the absence of other positive findings even after studying the smaller subgroups with higher levels of heavy metals, these results are clearly indicative of the minimal renal impact of living around nonferrous smelters that are currently complying with pollution regulations, even when soil contamination is still high.

Health risk for children from lead and cadmium near a non-ferrous smelter in Bulgaria

In an interdisciplinary approach the exposure to lead and cadmium of the population living in the vicinity of a Bulgarian non-ferrous metallurgical plant was studied to determine the routes of exposure. Two exposed villages situated 4 and 6 km SW and W, respectively,--in the plume of the plant's emissions--and a village for comparison situated 14 km SE of the plant were selected for the study. The blood of children aged 3-13 years from the exposed villages (n = 111) and the village for comparison (n = 18) was analyzed for lead (PbB) and cadmium (CdB) as well as for free erythrocyte protoporphyrin (FEP) and haematological parameters. A personal questionnaire concerning nutrition habits and life-style was filled in by interviewers of the children's parents. The cadmium levels in blood were within the variation range stated for Bulgaria. The exposed children had a mean CdB of 0.38 +/- 0.18 microgram/l (range 0.10-0.90 microgram/l) and the comparison group 0.31 +/- 0.35 microgram/l (0.06-1.42 micrograms/l). The mean PbB value measured in the exposed children was 240 +/- 96 micrograms/l (77-631 micrograms/l), while the mean value of PbB for the reference group was 149 +/- 57 micrograms/l (63-285 micrograms/l). Individual PbB levels > 150 and > 200 micrograms/l were found in 85% and 62%, respectively, of the exposed children and FEP > 80 micrograms/dl erythrocytes was detected in 21%. There was a concentration-response and a concentration-effect relationship (r = 0.51, D > 0.001) between PbB and FEP. According to the questionnaire only 10.3% of the interviewed families in the two exposed villages buy all food from the market, the others produce a significant part of their food themselves. The PbB levels of children who consume certain foods of local production (cabbage, cereals, poultry, and beef) were significantly higher compared to the PbB values of children whose families purchase these foods from the market. No significant relationship between lead in children's blood and the use of tin and ceramic utensils, drinking and irrigation water, hygiene habits, family tobacco smoking habits, playgrounds and traffic intensity were revealed. There was a significantly higher incidence of prematurely born babies in the exposed population. The proven relationship between lead intake via the food chain and existing significant health risks is the basis for risk communication. Measures aimed at healthier nutrition and life-style intend to contribute to decreasing the risk of the population living in the smelter region.

Exposure of children to lead and cadmium from a mining area of Brazil

During the past 50 years the Ribeira river valley, in the southern part of the state of São Paulo, Brazil, had been under the influence of the full activity of a huge lead refinery and mine working by the side of the river. The plant completely stopped all kinds of industrial activities at the end of 1995, and part of the worker population and their families still remain living nearby in small communities. The objective of the study was to assess the exposure of children to lead and cadmium in these areas, where residual environmental contamination from the past industrial activity still exists. Blood samples of 295 children aged 7 to 14 years, residing in rural and urban areas around the mine and the refinery, were collected. A questionnaire was given to gather information on food habits, leisure activities, father's past employment, current and former residential places, and other variables. Blood lead and cadmium concentrations were analyzed by graphite furnace atomic absorption spectrometry using Zeeman background correction. Cadmium values obtained in this population were mostly below established quantification limits (0.5 microg/dl). The median of blood lead level (BLL) obtained in children living close to the lead refinery was 11.25 microg/dl, and the median in other mining regions far from the refinery was 4.4 microg/dl. Logistic regression analysis was conducted to examine the independent contribution of selected variables in predicting BLL in these children. The following variables showed significant association with high BLL: residential area close to the lead refinery [odds ratio (OR)=10.38 (95% confidence interval (Cl)=4.86-23.25)], former father's occupational lead exposure [OR=4.07 (95% Cl=1.82-9.24)], and male gender [OR=2.60 (95% Cl=1.24-5.62)].

Determinants of cadmium burden levels in a population of children living in the vicinity of nonferrous smelters

This report covers part of the assessment of a site in northern France polluted by industrial metal emissions. Our objectives were to assess the cadmium burden in children aged 8 to 11 years and look for factors that affected it. A cross-sectional population-based study took place in 1996-1997 and included 400 children (200 in the metal-polluted area). The geometric mean of the blood cadmium (CdB) levels of children living on the polluted site was 0.51 microg/L (95% CI=[0.49-0.53]); that of the nonexposed children was 0.47 microg/L (95% CI=[0.45-0.49]) (P<0.01). The geometric mean of the urinary cadmium (CdU) levels of children living on the polluted site was 1.16 microg/g creatinine (95% CI=[1.01-1.34]); that of the nonexposed children was 0.99 microg/g creatinine (95% CI=[0.86-1.14]) (P=0.10). Mean CdB was higher among children within 4 km of a zinc smelter and consuming > or =500 ml of tap water daily (x1.34; 95% CI=[1.14-1.51]) compared with children living more than 4 km away and consuming <500 ml of tap water daily. Independently of this association, consumption of fish and shellfish (> or =once a week vs. <once a week) and homegrown vegetables (> or =once daily vs. <once daily) was associated with higher mean CdB levels, respectively: x 1.14; 95% CI=[1.07-1.21] and x 1.25; 95% CI=[1.04-1.50]. Neither sex nor age was associated with CdB. Mean CdU was associated with paternal occupational cadmium exposure.

Environmental exposure to lead in a population of adults living in northern France: lead burden levels and their determinants

As part of the assessment of a site in northern France polluted by metals from two smelters (in particular, lead, cadmium and mercury), a cross-sectional study was carried out which intended to estimate the levels of the lead burden of the adult population living on the site and the factors associated with these levels. The exposed zone included 10 municipalities in the Nord-Pas de Calais region, located in the vicinity of two non-ferrous metal smelters. The soils in these municipalities contained between 100 and 1700 ppm of lead. The non-polluted zone contained 20 municipalities from the same region, drawn randomly from those in the region of comparable size but free from any industrial lead exposure. The adult study population (301 men and 300 women) was stratified according to age, sex, employment status and exposure level. The inclusion criteria required subjects who were aged between 20 and 50 years and had been living in the exposed zone for at least 8 years; the exclusion criteria were pregnancy, cancer, kidney disease and diabetes. No more than 10% of the subjects participating could work at one of the two smelters. Data collection took place at home; visiting nurses interviewed subjects to complete a questionnaire and also took blood samples. The lead assay was performed by atomic absorption spectrometry. The geometric mean of the blood-lead levels was 74 microg/l, 95% CI = 69-80 among men and 49 microg/l, 95% CI = 46-53 among women. Blood-lead levels exceeding 100 microg/l were found among 30% of men and 12% of women. Several factors were associated with variation of the mean blood-lead level: the blood-lead level was significantly higher among the men for subjects living less than 1 km from the smelters (geometric mean x 1.3, 95% CI = 1.1-1.6), for those who drink alcoholic beverages (x 1.1, 95% CI = 1.0-1.2 for consumption of 30 g/day), those who smoke (x 1.2, 95% CI = 1.0-1.3 for 20 cigarettes/day), and for subjects with occupational exposure; among the women, for subjects living less than 1 km from the smelters (geometric mean x 1.5, 95% CI = 1.2-1.7), for those who drink alcohol (x 1.1, 95% CI = 1.1-1.2 for a daily consumption of 10 g), and for women living in a building constructed before 1948 (x 1.2, 95% CI = 1.0-1.4).