Blood lead levels and risk factors for lead poisoning among children in a Mexican smelting community

The authors evaluated mean blood lead levels (BLLs) and the prevalence of elevated BLLs in children 1-6 yr of age living in Torreón, Mexico, and assessed risk factors for lead exposure in these children. The study involved a simple random sample of households in the area around a local smelter, as well as a 2-stage cluster sample of neighborhoods and households in the remainder of Torreón. The geometric mean BLL of children in this study (N = 367) was 6.0 microg/dl (95% confidence interval [CI] = 5.2, 6.8) (0.29 microM/l [95% CI = 0.25, 0.33]). Twenty percent of the children had BLLs > or = 10 microg/dl (0.48 microM/l), and 5% had BLLs > or = 20 microg/dl (0.97 microM/l). In multivariate analyses, distance from the smelter, amount of income, and education level of the primary caregiver predicted BLLs. In the environmental risk factor subsample (n = 124), dust and soil lead levels were associated with BLLs and distance from the smelter. BLLs in this study were moderately high, but the levels were lower than those in other smelting communities prior to remediation.     

Environmental surveys in the areas of Bitterfeld,Hettstedt and a comparative area in 1992-2000

The aim of the environmental epidemiological study was to determine possible adverse effects on the health of children in the environmentally polluted areas of Bitterfeld and Hettstedt compared to the less polluted area of Zerbst (Eastern Germany). The changes of the health parameters were recorded together with the environmental changes during the time period of 6 years. The study design consisted of three repeated regional cross-sectional studies in 1992/93, 1995/96 and 1998/99. In total, 7,611 questionnaires could be analysed (participation rate: 89%, 75% and 75%). Children living in the most polluted area of Hettstedt had a noticeable higher risk for non-allergic respiratory diseases and symptoms compared to children living in the control area of Zerbst. From 1992 to 1999 a statistically significant decrease in the prevalences of these health outcomes was found. Children without indoor pollutants in their homes had the greatest benefit by the improvement of ambient air quality. The increase in lung function (FVC, FEV1) also underlines the improvement of the respiratory health. Children living in the polluted areas reported allergies more often (physician's diagnosis, allergy specific antibodies). The prevalence of asthma, the bronchial hyperreactivity and atopic eczema was increased within the observational period of 6 years. An increased prevalence was also shown for more severe allergic sensitisation (RAST classes > 17.5 kU/l), while the prevalence of hay fever increased slightly on a non-significant level. The burden with lead and cadmium was higher in children living in polluted areas and decreased during the study period except for 1997 where the lead concentration in blood increased according to the higher lead concentration in settled dust in Hettstedt at that time.     

Reduction of elevated blood lead levels in children in North Carolina and Vermont, 1996-1999

BACKGROUND: Few studies have examined factors related to the time required for children's blood lead levels (BLLs) > or = 10 microg/dL to decline to < 10 microg/dL. OBJECTIVES: We used routinely collected surveillance data to determine the length of time and risk factors associated with reducing elevated BLLs in children below the level of concern of 10 microg/dL. METHODS: From the North Carolina and Vermont state surveillance databases, we identified a retrospective cohort of 996 children < 6 years of age whose first two blood lead tests produced levels > or = 10 microg/dL during 1996-1999. Data were stratified into five categories of qualifying BLLs and analyzed using Cox regression. Survival curves were used to describe the time until BLLs declined below the level of concern. We compared three different analytic methods to account for children lost to follow-up. RESULTS: On average, it required slightly more than 1 year (382 days) for a child's BLL to decline to < 10 microg/dL, with the highest BLLs taking even longer. The BLLs of black children [hazard ratio (HR) = 0.84; 95% confidence interval (CI), 0.71-0.99], males (HR(male) = 0.83; 95% CI, 0.71-0.98), and children from rural areas (HR(rural) = 0.83; 95% CI, 0.70-0.97) took longer to fall below 10 microg/dL than those of other children, after controlling for qualifying BLL and other covariates. Sensitivity analysis demonstrated that including censored children estimated a longer time for BLL reduction than when using linear interpolation or when excluding censored children. CONCLUSION: Children with high confirmatory BLLs, black children, males, and children from rural areas may need additional attention during case management to expedite their BLL reduction time to < 10 microg/dL. Analytic methods that do not account for loss to follow-up may underestimate the time it takes for BLLs to fall below the recommended target level.     

Metal composition of ambient PM2.5 influences severity of allergic airways disease in mice

Children living in Hettstedt in eastern Germany have been reported to have a higher prevalence of sensitization to common aeroallergens than another cohort living in the neighboring city of Zerbst; these differences correlated with the presence of industrial air pollution. Samples of fine particulate matter (< 2.5 micro m aerodynamic diameter; PM(2.5)) collected in Hettstedt in 1999 had several-fold higher levels of zinc, magnesium, lead, copper, and cadmium than samples from Zerbst. To determine if the results from epidemiologic studies could be repeated in an animal model, we administered PM(2.5) from Hettstedt and Zerbst to ovalbumin-allergic mice. In Balb/c mice, PM(2.5) from Hettstedt, but not PM(2.5) from Zerbst or control filter extract, caused a significant increase in immediate responses to ovalbumin challenge when aspirated 2 hr before challenge, but not when aspirated immediately before sensitization 2 weeks earlier. Antigen-specific IgE was increased by Hettstedt PM(2.5) whether administered before sensitization or challenge. Airway responsiveness to methacholine aerosol and lung inflammatory cell numbers were significantly increased only in allergic mice exposed to Hettstedt PM(2.5) before challenge. Both Hettstedt and Zerbst PM(2.5) significantly increased lung injury parameters and proinflammatory cytokines. These results are consistent with epidemiologic findings and show that metal composition of ambient PM(2.5) influences the severity of allergic respiratory disease.     

Respiratory diseases and allergies in two polluted areas in East Germany.

This cross-sectional epidemiological study collected health data for 2,470 school children between 5 and 14 years of age (89% of eligible children) who had lived most of their lives in either one of two counties strongly impacted by industrial pollution (Bitterfeld and Hettstedt) or in a neighboring county without any sources of industrial pollution (Zerbst). The objective of the study was to examine whether regional differences--with respect to the occurrence of childhood respiratory diseases and symptoms or allergies--exist and, if such differences are found, whether they persist when we adjust for the effects of known risk factors such as medical and sociodemographic factors or factors related to the indoor environment. Controlling for medical, sociodemographic, and indoor factors, according to parental reports, children residing in Hettstedt have about a 50% increased lifetime prevalence for physician-diagnosed allergies, eczema, and bronchitis compared to children from Zerbst and about twice the number of respiratory symptoms such as wheeze, shortness of breath, and cough without cold. Sensitization to common aeroallergens according to skin prick tests [odds ratio (OR) = 1.38; 95% confidence interval (CI), 1.02-1.86] and specific IgE levels (OR = 1.75; CI, 1.31-2.33) was more common for children from Hettstedt than children from the nonpolluted county. Bitterfeld children, on the other hand, more often received a diagnosis of asthma and eczema than children residing in Zerbst and also showed slightly increased sensitization rates. In conclusion, industrial pollution related to mining and smelting operations in the county of Hettstedt were associated with a higher lifetime prevalence of respiratory disorders and an increased rate of allergic sensitization in children between the ages of 5 and 14 years. Further studies are needed to determine what role the high dust content of heavy metals plays in Hettstedt.     

Blood lead levels and associated sociodemographic factors among preschool children in the South Eastern region of China

Children are especially vulnerable to lead toxicity, and exposure to lead has been linked to poor school performance and delinquency in children and adolescents. Even low-level lead exposure [blood lead level (BLL) <10 μg/dL] can cause intellectual deficit. In China, BLLs in children decreased slightly after the phasing out of lead in gasoline, but few studies have examined the sociodemographic factors associated with BLL above 10 μg/dL. In this study, we sought to examine the hypothesis that sociodemographic factors predict BLLs. We measured BLLs of 1344 preschool children (3-5 years old) from the China Jintan Child Cohort Study. Children's sociodemographic and health statuses, as well as parental sociodemographic data, were collected using questionnaires. Regression models were used to explore the association between sociodemographic factors and log-transformed BLLs as well as the relationship between sociodemographic factors and the risk of BLL ≥10 μg/dL. We found the median BLL to be 6.2 μg/dL (range: 1.8-32.0 μg/dL); 8% of children had BLLs ≥10 μg/dL. Boys had a higher median BLL (6.4 μg/dL) than girls and were more likely to have BLL ≥10 μg/dL [odds ratio = 1.77, 95% confidence interval 1.14, 2.74]. BLLs increased as children aged, with a median BLL of 6.6 μg/dL among 5-year-old children. Children with siblings had a higher average BLL and greater prevalence of a BLL ≥10 μg/dL than those without siblings. Living in a crowded neighbourhood was also associated with increased BLLs. Mother's lower education, father's occupation (as professional worker) and parental smoking at home were associated with increased BLLs. This study shows that children in this area still have relatively high BLLs even after the phasing out of leaded gasoline. Both children's and parental factors and community condition are associated with increased BLLs. Future efforts are needed to identify other sources of exposure and develop targeted prevention strategies.     

Ten-year follow-up of blood lead levels with medical removal protection of shipyard workers

This cases report compared the short-term changes of BLL with medical removal intervention and follow-up the long-term changes of BLL afterward. During a physical examination in October 1992, a 44-year old shipyard welder was discovered to have a blood lead level (BLL) of 54.1 microg/dl. It was recommended that the shipyard remove this worker from his workplace. In 1993 the BLLs checked for this worker were 36.7 microg/dl in March and 32.0 microg/dl in April. After six months of medical removal, he returned to initial welding work. In 2002, we collected two blood samples from this worker for analysis in May and October. The results were 30.4 microg/dl and 31.6 microg/dl, respectively. Meanwhile, two other welding workers (case 2 and case 3) with BLLs over 40 microg/dl in the survey conducted at the same shipyard in 1992. It took 4 yr to let BLLs downed to less than 40 microg/dl. However, after the blood lead concentration drops to below 40 microg/dl, 10 yr long-term observation indicates that BLLs reduction level off and do not continue to go down in these three cases.     

Blood lead levels and risk factors for lead poisoning in children and caregivers in Chuuk State, Micronesia

Lead poisoning is a preventable environmental disease. Children and developing fetuses are especially vulnerable; even low blood lead levels (BLLs) are linked with learning and behavioral problems. We assessed children's and their caregivers' BLLs and risk factors for lead exposure in Chuuk State, Federated States of Micronesia. Children aged 2-6 years were randomly selected within 20 randomly selected villages. Children and caregivers provided venous blood, and caregivers offered information about possible risk factors for lead exposure. Mean BLLs were 39 microg/l for children and 16 microg/l for caregivers. Children with BLLs of > or = 100 microg/l (elevated) were 22.9 (95% CI: 4.5-116.0) times more likely to have a caregiver with an elevated BLL, 6.2 (95% CI: 1.4-27.3) times more likely to live on an outer island, and 3.4 (95% CI: 1.7-6.9) times more likely to have a family member who made lead fishing weights than did other children even after controlling for age and sex. For children, 61% of elevated BLLs could be attributed to making fishing weights. Caregivers with elevated BLLs were 5.9 (95% CI: 1.5-23.7) times more likely to live in a household that melted batteries than other caregivers even after controlling for age and education. For caregivers, 37% of the elevated BLLs could be attributed to melting batteries. The association of elevated BLLs in children and their caregiver suggests a common environmental exposure. Melting batteries to make fishing sinkers is a preventable source of lead exposure for children and their caregivers in Chuuk. Published by Elsevier GmbH.     

Lead poisoning among young children in Russia: concurrent evaluation of childhood lead exposure in Ekaterinburg,Krasnouralsk, and Volgograd

The Gore-Chernomyrdin Commission encouraged a binational collaboration to evaluate pediatric lead poisoning in Russia. The study evaluated children in three Russian cities: Krasnouralsk, a small city with minimal traffic centered around a copper smelter; and Ekaterinburg and Volgograd, both of which are large cities with multiple factories and heavy vehicular traffic. This project was the first international use of portable blood lead analysis instruments. In each city, at least 90% of children attending selected neighborhood kindergartens participated. We selected kindergartens on the basis of their proximity to industrial areas and major traffic corridors. We obtained capillary blood samples and analyzed for lead content and hemoglobin (Hgb) levels in the field, and collected environmental samples (i.e., indoor dust, tap water, play area soil, and interior and exterior paint) and analyzed for each participating school and in the homes of about 10% of the children who had elevated blood lead levels (BLLs; greater than or equal to 10 microg/dL). We calculated all age-, sex-, and city-specific geometric means using generalized estimating equations to account for covariance within kindergartens, and used multivariate logistic regression models to identify variables predictive of elevated BLLs. Overall, 23% of study children had elevated BLLs and 2% were anemic, defined as Hgb < 11 g/dL. Krasnouralsk had the highest geometric mean BLL (10.7 microg/dL), the highest percentage of children (60%) with elevated BLLs, and the highest percentage of anemic children (4%). All soil samples in Krasnouralsk had detectable lead levels. Volgograd was the only city that had paint samples with elevated lead levels. We found apparent city-specific differences in the percentages of children with elevated BLLs. Lead-contaminated soil and dust, which can result from lead-based automotive fuel and from lead-related industrial emissions, appear to be the most important routes of lead exposure of those evaluated in this study. Elevated lead levels found in paint samples from Volgograd may indicate old undercoats of lead-based paint that could represent a regionally rather than nationally important source of exposure.     

锌原卟啉作为环境铅污染人群筛查指标的可行性研究

目的探讨红细胞锌原卟啉（ZPP）应用于人群接触环境铅污染筛查指标的可行性。方法以紫金县某电池厂附近常住居民为调查对象,采集被调查者静脉血2～3 mL,采用血液锌原卟啉测定仪测定ZPP、石墨炉原子吸收光谱法测定血铅。儿童以血铅含量≥100μg/L、成年人以≥400μg/L为慢性铅中毒判定标准。结果共调查946名居民,其中1～13岁儿童174人、16～87岁成年人772人。儿童血铅含量超标率为14.9%（26/174）,儿童ZPP含量中位数为0.780μmol/L,血铅中位数为47.675μg/L,儿童ZPP含量与血铅含量的相关关系没有统计学意义（P〉0.05）。成人血铅含量超标率为9.5%（73/772）,成人ZPP含量中位数为0.740μmol/L,血铅中位数为69.572μg/L,成人ZPP含量与血铅含量呈弱相关关系（r=0.344,P〈0.05）。儿童血铅高水平组（血铅≥100μg/L）ZPP含量与血铅含量呈较强的相关关系（r=0.530,P〈0.05）,儿童血铅低水平组（血铅〈100μg/L）ZPP含量与血铅含量的相关关系没有统计学意义（P〉0.05）。成人血铅高水平组（血铅≥400μg/L）和低水平组（血铅〈400μg/L）的ZPP含量与血铅含量均具有相关关系（r分别为0.566、0.142,均P〈0.05）。结论成人血铅或儿童血铅水平较高时,ZPP可以作为环境铅污染人群筛查的指标。     

Binational study of pediatric blood lead levels along the United States/Mexico border

To evaluate lead exposure among children living in border communities, the states of Arizona and New Mexico in the United States (US), and the states of Sonora and Chihuahua in Mexico collaboratively requested that the Centers for Disease Control and Prevention (CDC) provide technical assistance to document pediatric blood lead levels (BLLs) in children living along this part of the US/Mexico border. Two studies were conducted to evaluate BLLs of children aged 1-6 years. In 1998, 1210 children were tested in the Arizona/Sonora study; in 1999, 874 children were tested in New Mexico/Chihuahua. Overall geometric mean BLL was 32.5 microg/l (95% Confidence Interval 31.5-33.5) with BLLs ranging from below limit of detection to 320.0 microg/l. Mean BLLs were higher among children living on the Mexican side of the border (43.2 microg/l) compared to those on the US side (22.3 microg/l). Mean BLLs ranged from 14.9 to 31.2 microg/l at the US sites and from 26.9 to 55.2 microg/l at the Mexican sites. This study used a convenience sample and cannot be considered representative of the general population. Nonetheless, the range of mean BLLs among the sites and especially the higher mean BLLs among children living in the border communities in Mexico suggests different exposures to lead and warrants further attention.     

Performance of several decision support tools for determining the need for systematic screening of childhood lead poisoning around industrial sites

BACKGROUND: Living around industrial sites may expose young children to lead and cause elevated blood lead levels (BLLs). Systematic screening for childhood lead poisoning is necessarily invasive but may be appropriate, depending on children's exposure levels. Our objective was to assess the performance of several decision support tools for determining the need for systematic BLL screening in children around industrial sites. METHOD: We used several exposure models to predict BLLs: the pharmacokinetic model IEUBK, the InVS dose model, and an empirical relation (Lewin, 1999) between soil concentrations and BLLs. We tested the BLLs (percentage of children with a BLL >100 micro g/l) that they predicted as well as threshold levels of soil pollution (200, 400, 500 ppm) for 71 situations for which the literature reports both environmental soil concentrations and BLLs in children aged 0-6 years. The tools' performance (sensitivity and specificity) was assessed by the rate of 'correct' (mass screening or not) decisions, judged retrospectively on the basis of measured BLLs, for different tolerated percentages of children with elevated BLLs. RESULTS: Decision support systems based on soil pollution levels were not adequately protective. The IEUBK and (updated) InVS mechanistic exposure models were the most effective in this setting. CONCLUSION: Exposure models may provide decision support if sufficient data about environmental contamination and dietary intake are available. Absolute performance measurement nonetheless remains difficult, in view of the limitations of the input data.     

Behavioral and Environmental Explanations of Elevated Blood Lead Levels in Immigrant Children and Children of Immigrants

Immigrant/refugee children sometimes have substantially higher blood lead levels (BLLs) than US-born children in similar environments. We try to understand why, by exploring the relationship between immigration status of mother and the BLLs of US-born children. We compared BLLs of children born in Michigan to immigrant and non-immigrant parents, using the Michigan database of BLL tests for 2002–2005, which includes the child’s race, Medicaid eligibility and address. We added census data on socio-demographic/housing characteristics of the child’s block group, and information about parents. Low parental education, single parent households, mothers’ smoking and drinking, all increase the child’s BLL. However, immigrant parents had fewer characteristics associated with high BLL than US born parents, and their children had lower BLLs than children of US-born mothers. Our findings suggest that prior findings of higher BLLs among immigrant/refugee children probably result from them starting life in high-lead environments.     

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.     

Blood lead levels of primary-school children in Penghu County,Taiwan: distribution and influencing factors

OBJECTIVES: The purpose of this study was to investigate the blood lead levels (BLLs) of primary-school children aged 7 to 12 in Penghu island and to determine the factors affecting their BLLs. METHODS: A total of 1,885 participants were recruited and BLLs were measured with a flameless atomic absorption spectrophotometer. A questionnaire was used to collect personal information. RESULTS: The results indicated that the mean BLL of primary-school children in Penghu was 6.0+/-2.4 microg/dl (1.0 approximately 29.3 microg/dl). The mean BLL of schoolboys ( n=1,046) was 6.3+/-2.6 microg/dl, with a maximum of 29.3 microg/dl, while the mean BLL of schoolgirls ( n=839) was 5.7+/-2.2 microg/dl, with a maximum of 23.4 microg/dl. Risk-factor analysis showed that personal characteristics (i.e., gender, frequency of milk consumption, grade levels) and geographic factors (i.e., levels of urbanization) significantly influence the BLLs. However, there was no significant impact on BLLs from drinking water, residential distance from a major road, and living close to lead-emitting sources. CONCLUSIONS: Geographical factors were highly associated with BLLs. The BLLs of the primary-school children living in the main Penghu island were lower than those in the other small islands.     

Demographic and socioeconomic factors associated with blood lead levels among Mexican-American children and adolescents in the United States

OBJECTIVE: This study was designed to assess demographic and socioeconomic differences in blood lead levels (BLLs) among Mexican-American children and adolescents in the United States. METHODS: We analyzed data from the Third National Health and Nutrition Examination Survey, 1988-1994, for 3,325 Mexican-American youth aged 1 to 17 years. The main study outcome measures included a continuous measure (microg/dL) of BLL and two dichotomous measures of BLL (> or =5 microg/dL and > or =10 microg/dL). RESULTS: The mean BLL among Mexican-American children in the United States was 3.45 microg/dL (95% confidence interval [CI] 3.07, 3.87); 20% had BLL > or =5 microg/dL (95% CI 15%, 24%); and 4% had BLL > or =10 microg/dL (95% CI 2%, 6%). In multivariate analyses, gender, age, generational status, home language, family income, education of head of household, age of housing, and source of drinking water were statistically significant independent predictors (p<0.05) of having higher BLLs and of having BLL > or =5 microg/dL, whereas age, family income, housing age, and source of drinking water were significant predictors (p<0.05) of having BLL > or =10 microg/dL. CONCLUSIONS: Significant differences in the risk of having elevated BLLs exist among Mexican-American youth. Those at greatest risk should be prioritized for lead screening and lead exposure abatement interventions.     

Blood lead levels in young children--United States and selected states, 1996-1999

Lead exposure adversely affects the cognitive development and behavior of young children (1). For children aged < 6 years, CDC has defined an elevated blood lead level (BLL) as > or = 10 microg/dL, but evidence exists for subtle effects at lower levels (2). Data from CDC's Third National Health and Nutrition Examination Survey, Phase 2 (1991-1994) (NHANES) showed that average BLLs in children had decreased approximately 80% since the late 1970s but that elevated BLLs remained more common among low-income children, urban children, and those living in older housing (3,4). Although these data provide national estimates of the prevalence of elevated BLLs among children, they do not provide information at the state or local level. To target prevention efforts and monitor progress toward reducing BLLs at the state and local level, CDC's Childhood Blood Lead Surveillance (CBLS) program supports state blood lead surveillance programs on the basis of blood lead tests from public and private clinical laboratories. This report summarizes data on BLLs in children aged 1-5 years from NHANES data collected in 1999 and children aged < 6 years from state surveillance data provided to CDC by 19 state surveillance programs during 1996-1998. The findings indicate that, despite the decreases in mean BLL among children, the problem remains concentrated on a local level. Surveillance efforts should be used to target screening efforts to communities at highest risk.     

Determinants of blood lead levels in children: a cross-sectional study in the Canary Islands (Spain)

The adverse effects of lead exposure on children are well known. Low blood lead levels (BLL) produce neurodevelopmental delay and cognitive disorders. However, since BLL thresholds for adverse effects on children's health are not known, the children population at risk of excessive lead exposure still has to be identified. This study was aimed at evaluating BLL in a children population of Gran Canaria (Canary Islands, Spain). Up to our knowledge, this is the first study to report on BLL in this population. Lead was identified and quantified in blood samples of 120 children, by means of Graphite furnace atomic absorption spectrometry (GFAAS). Lead was undetected in 80% of samples; BLL was 1 to 5 μg/dl in 15% of samples, and higher than 5 μg/dl in more than 4% of samples. BLL values in the evaluated children were low and similar to those described for other populations in Western countries. However, samples with the highest contamination (those in percentile 95) reached BLLs as high as 5.2 μg/dl. Positive associations were found between BLL and recent immigration (children adopted from non-western countries), and between BLL and parental smoking in children with low weight at birth. Since lead exposure in childhood may be a causative factor in adverse health trends - especially those involving the neurological system - and since threshold values for adverse lead effects are unknown, our finding that around 20% of the studied children had BLL higher than 1 μg/dl are of concern. Enhancing preventive measures for reducing lead exposure in children from the Canary Islands deserves further study.     

广州市使用无铅汽油十年后儿童血铅水平调查

目的 通过检测现阶段儿童血铅水平,了解广州市使用无铅汽油10年后的实施效果.方法 按分层随机抽样方法从广州市12个区、县级市中取市中心区、城郊区和郊县各1个,每个区、县再按分层各抽4所幼儿园和4所小学,从中取2373名2至12岁自愿抽血检测的儿童为调查对象,每名儿童肘部抽取静脉血1～2 ml,用0.1%Triton X-100和0.1%HNO3,对血样稀释20倍后直接以电感耦合等离子体质谱仪(ICP-MS)测定血铅.结果 2373名儿童中血铅最高值为330μg/L,最小值为10μg/L,几何均值为58.28μg/L,男童血铅均值(61.11μg/L)高于女童(55.37μg/L)(t=8.671,P=0.000).高血铅儿童共60名,占2.51%,其中男童36名(2.90%),女童24名(2.09%),差异无统计学意义(X2=1.594,P=0.207).与10年前全国情况(铅中毒平均流行率50%～85%、血铅均值120～160μg/L)相比高血铅儿童流行率减少了96.25%,血铅平均水平下降了58.37%.城乡结合部的白云区血铅均值为60.33μg/L,明显高于市中心的荔湾区和增城(血铅均值分别为58.09、56.72μg/L).结论 广州市使用无铅汽油10年后儿童铅中毒和血铅水平均大幅下降.     

Blood lead levels in children, China

To evaluate Chinese children's blood lead levels (BLLs) and identify its distribution features, we collected articles on children's BLLs published from 1994 to March 2004 using the Chinese Biomedical Disc and reviewed 32 articles eligible for the following criteria: (1) BLLs measured by Graphite Furnace Atomic Absorption Spectroscopy or Inductively Coupled Plasma-Mass Spectrometry; (2) strict quality control; (3) no lead pollution sources in the areas where the screened subjects live; and (4) sample size bigger than 100. We found that mean BLLs of Chinese children was 92.9 microg/L (37.2-254.2 microg/L), and 33.8% (9.6-80.5%) of the subjects had BLLs higher than 100 microg/L. Nine of the 27 provinces or cities reported had average BLLs 100 microg/L. Boys' BLL was 96.4 microg/L, significantly higher than girls' 89.4 microg/L (P<0.001). BLLs of children 6 years increased with age. The mean BLLs of children living in industrial and urban areas were significantly higher than those of children in suburbs and rural areas. Our results suggested that children's BLLs in China are higher than those of their counterparts in other countries due to its heavy lead pollution. Therefore, this is of great public health importance.