Association between children's blood lead levels, lead service lines, and water disinfection, Washington, DC, 1998-2006

Objective

Evaluate the effect of changes in the water disinfection process, and presence of lead service lines (LSLs), on children’s blood lead levels (BLLs) in Washington, DC.

Methods

Three cross-sectional analyses examined the relationship of LSL and changes in water disinfectant with BLLs in children <6 years of age. The study population was derived from the DC Childhood Lead Poisoning Prevention Program blood lead surveillance system of children who were tested and whose blood lead test results were reported to the DC Health Department. The Washington, DC Water and Sewer Authority (WASA) provided information on LSLs. The final study population consisted of 63,854 children with validated addresses.

Results

Controlling for age of housing, LSL was an independent risk factor for BLLs ≥10 μg/dL, and ≥5 μg/dL even during time periods when water levels met the US Environmental Protection Agency (EPA) action level of 15 parts per billion (ppb). When chloramine alone was used to disinfect water, the risk for BLL in the highest quartile among children in homes with LSL was greater than when either chlorine or chloramine with orthophosphate was used. For children tested after LSLs in their houses were replaced, those with partially replaced LSL were >3 times as likely to have BLLs ≥10 μg/dL versus children who never had LSLs.

Conclusions

LSLs were a risk factor for elevated BLLs even when WASA met the EPA water action level. Changes in water disinfection can enhance the effect of LSLs and increase lead exposure. Partially replacing LSLs may not decrease the risk of elevated BLLs associated with LSL exposure.     

The effect of lead-based paint hazard remediation on blood lead levels of lead poisoned children in New York City

Despite the widespread use of lead paint hazard control for children with lead poisoning, few controlled studies that estimate the effect of such control on children's blood lead levels have been published. This retrospective follow-up study examined the effects of lead hazard remediation and its timing on the blood lead levels of lead-poisoned children. From the New York City child blood lead registry, 221 children were selected who had an initial blood lead level of 20-44 micro g/dL between 1 July 1994 and 31 December 1996; were 6 months to 6 years of age; had a report of a follow-up blood lead test between 10 and 14 months after the initial test; had a lead-based paint hazard identified in the primary dwelling unit prior to the 10- to 14-month follow-up blood lead test; had resided or spent time at only one address with an identified lead-based paint hazard; and were not chelated. The decline in geometric mean blood lead levels from baseline to 10-14 months later was compared for children whose homes were remediated and whose homes were not remediated during the follow-up period. Regardless of remediation, geometric mean blood lead levels declined significantly from 24.3 micro g/dL at the initial diagnosis to 12.3 micro g/dL at the 10- to 14-month follow-up blood lead test (P<0.01). Among the 146 children whose homes were remediated the geometric mean blood lead levels declined 53% compared to 41% among the 75 children whose homes were not remediated by the follow-up blood lead test, a remediation effect of approximately 20% (P<0.01). After adjusting for potential confounders, the remediation effect was 11%, although it was no longer significant. Race was the only factor that appeared to confound the relationship: Black children had higher follow-up blood lead levels even after controlling for other factors, including the natural logarithm of the initial blood lead level. The effect of remediation appeared to be stronger for younger (10 to <36 months old) than for older (36 to 72 months old) children (P=0.06). While children in homes with earlier remediation (within less than 3 months) appeared to have greater declines in blood lead levels at the follow-up test than children in homes with later remediation (after 3 or more months), this trend was not significant when controlling for confounding factors. The findings of this study suggest that early identification of lead-poisoned children and timely investigation and abatement of hazards contribute to reducing blood lead levels. However, the apparent effect is modest and further research is needed to systematically test and improve the effectiveness of lead hazard controls.     

Case-control study of blood lead levels and attention deficit hyperactivity disorder in Chinese children

Background

Attention deficit/hyperactivity disorder (ADHD) and lead exposure are high-prevalence conditions among children.

Objective

Our goal was to investigate the association between ADHD and blood lead levels (BLLs) in Chinese children, adjusting for known ADHD risk factors and potential confounding variables.

Methods

We conducted a pair-matching case–control study with 630 ADHD cases and 630 non-ADHD controls 4–12 years of age, matched on the same age, sex, and socioeconomic status. The case and control children were systematically evaluated via structured diagnostic interviews, including caregiver interviews, based on the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., revised criteria (DSM-IV-R). We evaluated the association between BLLs and ADHD using the Pearson chi-square test for categorical variables and the Student t-test for continuous data. We then performed conditional multiple variables logistic regression analyses with backward stepwise selection to predict risk factors for ADHD.

Results

There was a significant difference in BLLs between ADHD cases and controls. ADHD cases were more likely to have been exposed to lead during childhood than the non-ADHD control subjects, with adjustment for other known risk factors [children with BLLs ≥ 10 μg/dL vs. ≤ 5 μg/dL; OR = 6.0; 95% confidence interval (CI) = 4.10–8.77, p < 0.01; 5–10 μg/dL vs.≤ 5 μg/dL, OR = 4.9; 95% CI = 3.47–6.98, p < 0.01]. These results were not modified by age and sex variables.

Conclusions

This was the largest sample size case–control study to date to study the association between BLLs and ADHD in Chinese children. ADHD may be an additional deleterious outcome of lead exposure during childhood, even when BLLs are < 10 μg/dL.     

Occurrence and determinants of increases in blood lead levels in children shortly after lead hazard control activities

This study is an examination of the effect of lead hazard control strategies on children's blood lead levels immediately after an intervention was conducted as part of the US Department of Housing and Urban Development's Lead-Based Paint Hazard Control Grant Program. Fourteen state and local government grantees participated in the evaluation. The findings indicated an overall average reduction in the blood lead levels of 869 children soon after the implementation of lead hazard controls. However, 9.3% of these children (n = 81) had blood lead increases of 5 microg/dL or more. Data routinely collected as part of the evaluation, as well as additional information supplied by the individual programs, were used to determine potential reasons for these observed increases in blood lead. A logistic regression analysis indicated that three principal factors were associated with the blood lead increases: the number of exterior deteriorations present in the child's home (prior to intervention), the educational level of the female parent or guardian of the child, and the child's age. The statistical analysis did not find evidence that children living in households that either did not relocate or relocated for less than the full work period were significantly more likely to have a blood lead increase equal to or greater than 5 microg/dL than children living in households that fully relocated. Statistical analyses also did not reveal any single interior strategy to be more or less likely than others to be associated with a blood lead increase of 5 microg/dL or more.     

鞍山市儿童血铅水平状况调查

目的了解鞍山市3~6岁儿童铅中毒情况并探讨血铅水平与不同地区、年龄、性别的关系。方法采用分层整群抽样法,抽取鞍山市5所托幼机构的3~6岁408名学龄前儿童（男孩217名,女孩192名）,用石墨炉法测定血铅,并对其父母进行相关知识问卷调查。结果鞍山市不同地区幼儿园间儿童血铅水平差异有统计学意义（P〈0.05）。男孩与女孩在同年龄组间血铅水平差异无统计学意义（P〉0.05）,但不同年龄组男孩的血铅水平差异有统计学意义（P〈0.01）。结论目前鞍山市儿童铅中毒问题比较严重,应采取行之有效的干预措施。     

Surveillance of elevated blood lead levels in children in Torreon, Coahuila, Mexico, 1998-2010

Introduction

Because children exposed to lead have a very high health risk, surveillance and prevention programs are very important to avoid short- and long-term health effects.

Objectives

To describe the trend for the blood lead levels over a 12-year period in environmentally exposed children and to document the actions implemented to reduce the blood lead levels.

Materials and methods

We performed a retrospective cohort study of children aged 0–15 years who were enrolled in the Coahuila Health Secretary's Childhood Blood Lead Level Surveillance program. This database includes children from the city of Torreon, Coahuila, Mexico, where the biggest smelter in Latin America is located.

Results

A total of 151,322 observations were analyzed in the study. The percentage of samples with elevated blood lead levels decreased from 84.9% to 10.4% during 1998–2010, and the decrease was greater in girls than in boys.

Conclusion

According to the results of our study, the majority of strategies and activities to decrease blood lead levels in an environmentally exposed population should be focused on children aged 0–5 years, on the home environment, on preventing fugitive emissions from smelters and other sources and on the proper disposal and confinement of industrial residues.     

Impact of lead transport on children's blood and environmental lead levels

Introduction: A lead monitoring project was established in 1996 to monitor the environmental and health effects of lead being transported through a remote town in tarpaulin‐covered trucks. Methods: Dust samples from sites on the transport route were collected at 3–6 monthly intervals between 1996 and 1999. Annual blood lead testing clinics, offering voluntary testing to children, were conducted from 1997 to 1999. Results: Of the 55 dust samples analysed, only nine contained particles of lead concentrate and these were present at very low levels. During the project 167 children were tested. The geometic mean of blood lead levels in 1997, 1998 and 1999 were 4.5 μg/dL, 5.0 μg/dL and 5.1 μg/dL, respectively (all within the normal range). Residence on the transport route was not associated with higher lead levels (P > 0.05). Conclusions: Lead transport was not associated with any detectable environmental contamination or increase in children's blood lead levels.     

南京市7～12岁儿童血铅水平状况调查

目的了解南京市7～12岁儿童血铅水平状况。方法对南京市1 113名7～12岁儿童血铅水平进行调查,采用石墨炉原子吸收光谱法进行检测。结果南京市儿童血铅均值为36.90μg/L,铅中毒率为1.8%;血铅水平男童为39.07μg/L,女童为34.55μg/L,差异有统计学意义(P<0.05);各年龄组儿童血铅水平差异有统计学意义(P<0.05)。结论南京市7～12岁儿童血铅平均水平及中毒率低于全国,但仍需通过环境治理及监管降低环境铅水平,同时加强健康宣传教育,提高儿童及家长防护意识。     

婴幼儿血铅水平与出生前后铅暴露关系的队列研究

[目的]了解婴幼儿血铅水平与出生前后铅暴露的关系,为防治和减轻铅暴露对婴幼儿的不利影响提供科学依据。[方法]采用前瞻性队列研究的方法,在环境铅污染区建立新婚夫妇研究队列,分别在女方怀孕前、孕中期、分娩时以及子代婴幼儿期采集血样,并用石墨炉原子吸收法测定血铅水平;纵向分析出生前后铅暴露对婴幼儿血铅水平的影响。[结果]基线血铅明显高于孕中血铅和脐带血铅,且孕中血铅、脐带血铅与基线血铅高度相关(P<0.01);婴幼儿血铅要明显高于母亲基线血铅、孕中血铅和脐带血铅(P<0.01),且婴幼儿血铅与母亲基线血和脐带血血铅均呈正相关,但差异均无显著性(P>0.05)。[结论]婴幼儿血铅水平与出生前宫内暴露和出生后环境暴露均有关,但与后者关系可能更密切。     

株洲市门诊儿童血铅水平及其影响因素的流行病学研究

目的了解株洲市门诊儿童血铅水平及其影响因素,为防治铅中毒提供针对性建议。方法对株洲地区儿科门诊的1 200例1月~14岁儿童进行问卷调查,并测定其静脉血铅水平和血清铁、钙、铜、镁、锌含量。结果 1)门诊儿童血铅水平平均为(96.1±64.4)μg/L,≥100.0μg/L者检出率达28.7%。2)逐步回归分析:血铅水平与全血铁、钙、铜含量呈负相关,而不认为血铅水平与全血镁、锌含量存在显著关系。3)Logistic回归分析:母亲年龄较大、常补充钙/铁/锌制剂、常食用乳类和乳制品、散居是儿童血铅含量≥100μg/L的保护因素。母亲文化程度低、父亲吸烟、男童、常在交通繁忙地带散步/玩耍、进食前几乎不洗手、常咬文具/玩具、常食爆米花、常吸吮手指/啃手指甲、常玩橡皮泥、常服中草药、经常饮用罐装饮料、住所距离主干道较近、居室有墙皮脱落、住所楼层较低、大年龄儿童是儿童血铅含量≥100μg/L的危险因素。结论株洲市门诊儿童血铅水平≥100.0μg/L检出率较高,当地政府和社会应以改善生态环境、加强营养干预、普及健康教育、落实行为指导为切入点,减轻儿童铅暴露及其危害。     

合肥市七区2008-2009年儿童血铅水平及其影响因素研究

【目的】 描述2008-2009年合肥市七区儿童血铅水平,分析其影响因素,为儿童血铅防治提供循证依据。 【方法】 应用分层整群抽样方法,2008-2009年选取合肥市七个地区3 394例0～6岁儿童为调查对象,采用钨舟原子吸收光谱仪检测血铅;同时,开展儿童血铅影响因素问卷调查。 【结果】 合肥市0～6岁男童血铅平均水平为(47.06±23.30) μg/L,女童血铅平均水平为(45.09±23.30) μg/L。1～岁组、2～岁组男童血铅平均水平高于其他年龄组;0～岁组、1～岁组、2～岁组女童血铅水平高于其他年龄组;除包河区和高新区外,其余各区及全市2009年血铅水平均较2008年显著降低,且2009年全市儿童铅中毒率较2008年显著降低;父亲从事铅相关职业、住所距主干道≤30 m、户外活动时间>3 h、进食前不洗手等成为影响儿童血铅水平过高的主要危险因素。 【结论】 目前合肥市的儿童血铅水平呈下降趋势,应进一步加强铅中毒危害的宣传教育,对重点人群采取行之有效的干预措施。     

A geospatial analysis of the effects of aviation gasoline on childhood blood lead levels

Background: Aviation gasoline, commonly referred to as avgas, is a leaded fuel used in small aircraft. Recent concern about the effects of lead emissions from planes has motivated the U.S. Environmental Protection to consider regulating leaded avgas.Objective: In this study we investigated the relationship between lead from avgas and blood lead levels in children living in six counties in North Carolina.Methods: We used geographic information systems to approximate areas surrounding airports in which lead from avgas may be present in elevated concentrations in air and may also be deposited to soil. We then used regression analysis to examine the relationship between residential proximity to airports and North Carolina blood lead surveillance data in children 9 months to 7 years of age while controlling for factors including age of housing, socioeconomic characteristics, and seasonality.Results: Our results suggest that children living within 500 m of an airport at which planes use leaded avgas have higher blood lead levels than other children. This apparent effect of avgas on blood lead levels was evident also among children living within 1,000 m of airports. The estimated effect on blood lead levels exhibited a monotonically decreasing dose–response pattern, with the largest impact on children living within 500 m.Conclusions: We estimated a significant association between potential exposure to lead emissions from avgas and blood lead levels in children. Although the estimated increase was not especially large, the results of this study are nonetheless directly relevant to the policy debate surrounding the regulation of leaded avgas.     

2 705例儿保门诊体检儿童血铅检测结果分析

目的了解兰州市儿童铅中毒患病情况,提出预防措施.方法用石墨炉原子吸收光谱法,对兰州市妇幼保健院儿童保健科正常体检的2 705例0～6岁儿童进行血铅检测.结果2 705例儿童中,铅中毒(血铅浓度I＞100μg/L)的检出率为57.1%,男性高于女性(P=0.000);年龄越大,检出率越高(P=0.000);检出率在春秋季高于冬夏季节(P=0.016＜0.05).结论兰州市0～6岁儿保门诊体检儿童铅中毒的检出率较高,男性高于女性,年龄越大,检出率越高,春秋季是铅中毒的高发季节,应予以足够重视,采取适当措施,防治铅中毒.     

2705例儿保门诊体检儿童血铅检测结果分析

目的:了解兰州市儿童铅中毒患病情况,提出预防措施。方法:用石墨炉原子吸收光谱法,对兰州市妇幼保健院儿童保健科正常体检的2 705例0~6岁儿童进行血铅检测。结果:2 705例儿童中,铅中毒(血铅浓度≥100μg/L)的检出率为57.1%,男性高于女性(P=0.000);年龄越大,检出率越高(P=0.000);检出率在春秋季高于冬夏季节(P=0.016<0.05)。结论:兰州市0~6岁儿保门诊体检儿童铅中毒的检出率较高,男性高于女性,年龄越大,检出率越高,春秋季是铅中毒的高发季节,应予以足够重视,采取适当措施,防治铅中毒。     

江苏省正常人群血锰、血铅负荷水平调查

目的了解江苏省正常人群体内锰(Mn)、铅(Pb)负荷水平,评估其对正常人群健康的影响,为中毒原因的筛查及疾病的诊断、预防和控制重金属污染提供依据。方法采用多阶段分层随机整群抽样方法,抽取具有代表性的3个市/县,共调1 289人,采集全血样本,采用离子耦合质谱法(ICP-MS)检测。结果正常人群中血Mn负荷为0.58～32.93μg/L,均值为(9.02±0.69)μg/L;血Pb负荷为1.83～151.90μg/L,均值为(20.71±5.01)μg/L;异常率均较高。血Pb异常率苏北>苏中>苏南,血Mn异常率苏北>苏南>苏中;16～岁组异常率最高;男性异常率大于女性。结论江苏地区正常人群体内Mn、Pb的负荷水平均值较低,但异常率较高,存在地区、年龄和性别之间的差异。应重视江苏地区特别是经济欠发达地区重金属污染的现状,加强环境保护。     

临沂市区0～6岁儿童血铅水平调查

【目的】了解临沂市区0～6岁儿童血铅水平及铅中毒流行状况，为制定防止环境铅污染。保护儿童健康政策提供科学依据。【方法】在严格质量控制下．应用原子吸收光谱法对临沂市区2670名0～6岁儿煮进行血铅含量检测并统计分析。【结果】2670名0～6岁儿童血铅水平均值为0．344μmol／L。其中，血铅含量≥0．483μmol／L者387例．铅中毒检出率为14．5％。不同性别间儿童血铅水平均值和铅中毒率差异均无显著性（P〉0．05）；随着年龄增加。0～岁组、1～岁组、2～岁组血铅水平均值有逐渐增高趋势，而2～岁组、3～岁组、4～岁组随着年龄增加叉表现出血铅水平均值略有下降趋势。【结论】临沂市区0～6岁儿童血铅水平较高，铅中毒流行状况不容乐观，应引起儿童家长乃至全体市民的高度重视。     

Status of children's blood lead levels in Pakistan: implications for research and policy

OBJECTIVES: Data on blood lead levels, sources of lead and health effects were reviewed among children in Pakistan. METHODS: A systematic review was conducted of published studies found through PubMed, an index of Pakistani medical journals PakMediNet and unpublished reports from governmental and non-governmental agencies in Pakistan. RESULTS: With the exception of a few studies that had adequate sample sizes and population-based samples, most studies were small and used convenience sampling methods to select study subjects. Overall, blood lead levels declined from 38 microg/dl in 1989 to 15 microg/dl in 2002. The major sources of lead that directly or indirectly resulted in lead exposure of children included: leaded petrol; father's occupation in lead-based industry; leaded paint; traditional cosmetics; and remedies. Apart from leaded petrol, there was no information regarding the level of lead in other sources such as paints and the household environment. Very little information was available regarding the adverse health effects of lead among children. CONCLUSION: The phasing out of leaded petrol was a commendable mitigation measure undertaken in July 2001 in Pakistan. A comprehensive assessment is now needed urgently to explore other sources of lead contributing to adverse health effects, and to plan intervention options with the ultimate goal of reducing the burden of disease due to lead exposure.     

血铅结果对血细胞参数的影响

目的 了解血铅对儿童血液系统的影响及血铅与血细胞参数的关系.方法 对北京市1 584名体检儿童进行血铅及血细胞的检测.按血铅值分为高铅(血铅≥100μg/L)和低铅(血铅<100μg/L)两组.结果 高铅组的血红蛋白、红细胞比积、平均红细胞体积和红细胞平均血红蛋白含量均低于低铅组,经比较有显著性差异(t分别为2.38、2.47、2.39、2.41,均P<0.05).血铅与血红蛋白、红细胞比积、平均红细胞体积、红细胞平均血红蛋白含量呈负相关关系(r分别为-0.156、-1.571,均P<0.05;-0.219、-0.249,均P<0.01).结论 血铅升高(≥100μg/L)的儿童患低色素性小细胞贫血的几率较血铅正常的儿童高,虽然其贫血的指标无明显变化,但要重视潜在贫血的可能性.     

The decay of blood lead levels in workers suspended under the control of lead at work regulations

AIMS: To study the rate of decline in blood lead levels post-suspension under Control of Lead at Work Regulations (CLAW) and thereby suggest sampling frequencies for follow-up blood lead measurements. METHODS: A retrospective cohort of lead workers with blood lead levels over the current suspension level were identified from blood lead records. Data on their suspension and follow-up blood lead measurements were obtained. RESULTS: Sixteen per cent of the identified cohort did not appear to return to lead work under CLAW. Twenty-seven suspension cases with an initial mean blood lead of 79 microg/dl (3.82 micromol/l) formed the dataset for analysis of decline in blood lead levels. The mean length of time between the blood sample indicating suspension and the first follow-up blood sample was 32 days. The mean length of suspension under CLAW was 61 days. The mean initial rate of blood lead decay was 0.659 microg/dl per day (0.032 micromol/l per day), although with a wide range. The rate of decline in blood lead after suspension was increased by the blood lead level at suspension, but was decreased by increasing past cumulative exposure. CONCLUSIONS: A follow-up blood lead sample 1 month after suspension should show a mean decrease between 13 and 26 microg/dl (0.63-1.25 micromol/l), which is substantially greater than that due to analytical 'noise' associated with two sequential measurements (approximately 5 microg/dl). Therefore, a follow-up blood sample taken around 3-4 weeks after suspension would seem practical. A decrease in blood lead of 7-8 mug/dl (0.36 micromol/l) or less in the month after suspension may suggest continuing lead exposure.     

A study of pediatric blood lead levels in a lead mining area in South Africa

This study aimed to determine the blood lead distributions among young children in the lead mining town of Aggeneys in South Africa's Northern Cape Province, and in the comparison community of Pella, about 40 Km away. A further objective of the study was to explore factors associated with elevated blood lead levels. Children aged between 6 and 10 years (average age, 8 years) were studied, 86 from Aggeneys and 68 from Pella. The results showed that blood lead levels among the children of Aggeneys averaged around 16 microg/dL, while in Pella the mean blood lead level equaled 13 microg/dL. Overall, children with raised blood lead levels performed less well at school relative to other children. Within Aggeneys, fathers of "high" lead children tended to shower at work rather than at home, which may have been insufficient to prevent lead from being transported into the home. In conclusion, more stringent environmental control measures are needed, as well as stricter personal hygiene measures, to prevent childhood lead exposure in the mining community.