Children's Lead Levels Research Articles

Blood lead concentrations in sub‐Saharan African children below 6 years: systematic review

To assess the geometric mean of blood lead levels in children aged below 6years living in sub-Saharan Africa. Search strategies were developed in MEDLINE, Web of Science and Google scholar system, supplemented by screening of references from included papers and review articles. Studies including children younger than 6years residing in sub-Saharan Africa (SSA) were eligible. The studies were assessed for quality of methods for blood collection, for participants' recruitment and for quality control for lead analyses. Data were extracted and synthetised by estimating the mean weighted by sample size. A total of 11148 published papers were identified with only 16 studies conducted in SSA. Only nine of them were relevant of inclusion criteria. The weighted mean of blood lead levels was 13.1μg/dl. Five of included studies were classified as being less likely to present selection bias, having performed venipuncture and adequate quality control for lead analyses. The weighted mean from analyses involving only these studies was 16.2μg/dl. Six of the included studies reported the prevalence of blood lead levels ≥10μg/dl; levels ranged from 7.0% to 70.9%. Only one study reported the prevalence of blood lead levels ≥5μg/dl (50%). The geometric mean of blood lead levels in sub-Saharan African children is still elevated relative to the US children. The new standard from the Centers for Disease Control and Prevention (5μg/dl) implies that important efforts should be directed towards the initiation (or reinforcement) of prevention programmes and thorough research studies in sub-Saharan Africa.

Blood lead levels in children after phase-out of leaded gasoline in Kinshasa, the capital of Democratic Republic of Congo (DRC)

BackgroundThe phasing out of lead from gasoline has resulted in a significant decrease in blood lead levels (BLLs) in children during the last two decades. Tetraethyl lead was phased out in DRC in 2009. The objective of this study was to test for reduction in pediatric BLLs in Kinshasa, by comparing BLLs collected in 2011 (2 years after use of leaded gasoline was phased out) to those collected in surveys conducted in 2004 and 2008 by Tuakuila et al. (when leaded gasoline was still used).MethodsWe analyzed BLLs in a total of 100 children under 6 years of age (Mean ± SD: 2.9 ± 1.6 age, 64% boys) using inductively coupled argon plasma mass spectrometry (ICP – MS).ResultsThe prevalence of elevated BLLs (≥ 10 μg/dL) in children tested was 63% in 2004 [n = 100, GM (95% CI) = 12.4 μg/dL (11.4 – 13.3)] and 71% in 2008 [(n = 55, GM (95% CI) = 11.2 μg/dL (10.3 – 14.4)]. In the present study, this prevalence was 41%. The average BLLs for the current study population [GM (95% CI) = 8.7 μg/dL (8.0 – 9.5)] was lower than those found by Tuakuila et al. (F = 10.38, p <0.001) as well as the CDC level of concern (10 μ/dL), with 3% of children diagnosed with BLLs ≥ 20 μg/dL.ConclusionThese results demonstrate a significant success of the public health system in Kinshasa, DRC-achieved by the removal of lead from gasoline. However, with increasing evidence that adverse health effects occur at BLLs < 10 μg/dL and no safe BLLs in children has been identified, the BLLs measured in this study continue to constitute a major public health concern for Kinshasa. The emphasis should shift to examine the contributions of non-gasoline sources to children’s BLLs: car batteries recycling in certain residences, the traditional use of fired clay for the treatment of gastritis by pregnant women and leaded paint.

Niveles intelectuales y ansiedad en niños con intoxicación plúmbica crónica. Colegio “María Reiche”. Callao-Perú, 2002

Objetivo: Determinar la asociación entre intoxicación plúmbica crónica y niveles intelectuales, y la asociación entre intoxicación plúmbica crónica y ansiedad, en niños del colegio “María Reiche”-Callao. Materiales y Métodos: Se realizó un estudio observacional transversal en 39 niños que participaron en el dosaje de plomo en sangre hecho por la Dirección General de Salud Ambiental en el año 2002. Se midió el coeficiente intelectual y determinó el nivel intelectual, y se aplicó la lista de chequeo de ansiedad. Se categorizó a los niños, según sus niveles de plomo en sangre, en no intoxicados (niveles &amp;lt; 10 µg/dL) e intoxicados (niveles ≥ 10 µg/dL). Se aplicó las pruebas chi-cuadrado y prueba t con un p &amp;lt;0,05. Resultados: El coeficiente intelectual de los niños intoxicados fue 85,51±12,56, los niveles de plomo fueron 26,54±9.42 µg/ dL en los niños con nivel intelectual bajo (fronterizo e inferior). Los niveles intelectuales y las categorías de plomo en sangre se asociaron con un p=0,355. Los grados de ansiedad y las categorías de plomo en sangre se asociaron con un p=0,03. La distribución t encontró diferencia de medias entre los niveles de plomo en los grupos con ansiedad leve y marcada (p=0,024). Conclusiones: Se encontró asociación entre la intoxicación plúmbica crónica y el grado de ansiedad; sin embargo, no se encontró asociación entre los niveles intelectuales y la intoxicación plúmbica crónica.

Advancing Knowledge on the Environment and Its Impact on Health, and Meeting the Challenges of Global Environmental Change

Advancing Knowledge on the Environment and Its Impact on Health, and Meeting the Challenges of Global Environmental Change

Lead Exposure Assessment for Chinese Children

Lead is unique in that man-made sources contribute almost solely to exposure in the post-industrial era.The adverse health effects caused by low-level exposure to Pb have been reviewed. Such health effects include neurological impairment and deficits in the functioning of the central nervous system. Blood lead level is an important index which can measure how seriously children have been exposed to lead. By consulting the papers on the studies of children’s blood lead levels, the sources and influencing factors of blood lead levels of children in China were reviewed in the present paper, meanwhile, some suggestions were provided to decrease the lead contact probability and improve children’s health.

The burden of disease from pediatric lead exposure at hazardous waste sites in 7 Asian countries

Identification and systematic assessment of hazardous wastes sites in low and middle-income countries has lagged. Hazardous waste problems are especially severe in lower income Asian countries where environmental regulations are non-existent, nonspecific or poorly enforced. In these countries extensive unregulated industrial development has created waste sites in densely populated urban areas. These sites appear to pose significant risks to public health, and especially to the health of children.To assess potential health risks from chemical contamination at hazardous waste sites in Asia, we assessed 679 sites. A total of 169 sites in 7 countries were classified as contaminated by lead. Eighty-two of these sites contained lead at levels high enough to produce elevated blood lead levels in surrounding populations.To estimate the burden of pediatric lead poisoning associated with exposure to lead in soil and water at these 82 lead-contaminated sites, we used standard toxicokinetic models that relate levels of lead in soil and water to blood lead levels in children. We calculated blood lead levels, and we quantified losses of intelligence (reductions in IQ scores) that were attributable to lead exposure at these sites.We found that 189,725 children in the 7 countries are at risk of diminished intelligence as a consequence of exposure to elevated levels of lead in water and soil at hazardous waste sites. Depending on choice of model, these decrements ranged from 4.94 to 14.96 IQ points. Given the restricted scope of this survey and the conservative estimation procedures employed, this number is almost certainly an underestimate of the full burden of disease.Exposure to toxic chemicals from hazardous waste sites is an important and heretofore insufficiently examined contributor to the Global Burden of Disease.

Lead (Pb) in Tap Water and in Blood: Implications for Lead Exposure in the United States

Lead is widely recognized as one of the most pervasive environmental health threats in the United States, and there is increased concern over adverse health impacts at levels of exposure once considered safe. Lead contamination of tap water was once a major cause of lead exposure in the United States and, as other sources have been addressed, the relative contribution of lead in water to lead in blood is expected to become increasingly important. Moreover, prior research suggests that lead in water may be more important as a source than is presently believed. The authors describe sources of lead in tap water, chemical forms of the lead, and relevant U.S. regulations/guidelines, while considering their implications for human exposure. Research that examined associations between water lead levels and blood lead levels is critically reviewed, and some of the challenges in making such associations, even if lead in water is the dominant source of lead in blood, are highlighted. Better protecting populations at risk from this and from other lead sources is necessary, if the United States is to achieve its goal of eliminating elevated blood lead levels in children by 2020.

Health risk assessment of lead for children in tinfoil manufacturing and e-waste recycling areas of Zhejiang Province, China

Tinfoil manufacturing and electronic waste (e-waste) recycling remain rudimentary processes in Zhejing Province, China, which could account for elevated blood lead levels (BLLs) and health impacts on children. We assessed the potential health risks of lead in tinfoil manufacturing and e-waste recycling areas. 329 children in total aged 11–12 who lived in a tinfoil manufacturing area (Lanxi), an e-waste recycling area (Luqiao) and a reference area (Chun'an) were studied. Lead levels in children's blood were determined by inductively coupled plasma mass spectrometer (ICP-MS). Blood urea nitrogen (BUN), serum creatinine, serum calcium, δ-Aminolaevulinic acid (δ-ALA) and intelligence quotient (IQ) were also measured. Geometric mean of BLLs in Lanxi, Luqiao and Chun'an were 8.11μg/dL, 6.97μg/dL, and 2.78μg/dL respectively, with 35.1%, 38.9% and 0% of children who had BLLs above 10μg/dL. The BLLs in exposed areas were much higher than those in the control area. Lanxi children had higher creatinine and calcium than Chun'an children, and Luqiao children had higher δ-ALA and lower calcium than Chun'an children. No significant differences of IQ were observed between Lanxi, Luqiao and Chun'an, however a negative relationship between BLLs and IQ was shown for the study children. The results indicated that lead pollution from e-waste recycling and tinfoil processing appears to be a potential serious threat to children's health.

Human biomonitoring in Israel: Past, present, future

The first human biomonitoring (HBM) studies in Israel in the 1970s and 80s focused on measuring exposure to polychlorinated biphenyls (PCBs) and organochlorine insecticides in the general population and organophosphate pesticides in agricultural workers. In the late 1990 s, a regional human biomonitoring study found differences in blood lead levels in children from Israel, Jordan, and the Palestinian Authority. Taken together with data on time trends in lead emissions in Israel, the study indicated the benefits from phasing out of leaded gasoline. More recently, a pilot study in pregnant women in Jerusalem, conducted in collaboration with the US-CDC, found widespread exposure to phthalates, organophosphate pesticides, and the carbamate bendiocarb. Creatinine-adjusted total dimethyl (DM) metabolite concentrations were between 4 and 6 times higher than populations of pregnant women in the United States. The Israel Ministry of Health is currently collaborating with the Hebrew University of Jerusalem and Al Quds University to study exposures to phthalates and organophosphates in pregnant women in Israel and the Palestinian Authority. The Israel Ministry of Health has also begun the first National Biomonitoring Study to measure exposures to bisphenol A, phthalates, organophosphates, polyaromatic hydrocarbons, the phytoestrogens genistein and daidzein, and cotinine in the Israeli adult population. This study is being carried out in collaboration with the University of Erlangen-Nuremberg in Germany. Until recently, HBM programs in Israel were targeted at selected occupational groups (workers potentially exposed to metals, volatile organic compounds (VOCs), and cholinesterase inhibitors) and naval divers potentially exposed to environmental contaminants. The future of HBM in Israel lies in extending such programs to measuring exposures in representative samples of the general population, increasing international collaboration in this field, developing analytical capacity and expertise, and increasing use of human biomonitoring studies in forming and evaluating environmental health policy.

Airborne inhalable metals in residential areas of Delhi, India: distribution, source apportionment and health risks

The inhalable fraction of ambient particles (particulate matter with aerodynamic diameter less than 10μm, denoted by PM10) collected at three residential sites in Delhi, India during December 2008–November 2009 were characterized with respect to 8 major and trace metals (Fe, Mn, Cd, Cu, Ni, Pb, Zn and Cr). Mean annual 24–h PM10 levels varied from 166.5–192.3μg m–3 at the sites (8–10 times of the WHO limit). Weekday/weekend effects on PM10 and associated metals were investigated. Significant seasonal variations (ANOVA, p<0.001) in species concentrations were observed with PM10 and crustal metals peaking in summer while anthropogenic metals peaked in winter. Spatial distributions of metals were influenced mainly by proximity to traffic and industrial areas. Influence of meteorological parameters on ambient metal distributions was also studied. Source apportionment by principal component analysis–multiple linear regression (PCA–MLR) identified three major sources: crustal (49–65%), vehicular (27–31%) and industrial (4–21%). As a part of health risk assessment, calculated theoretical estimates of blood lead levels in children varied from 10.2–13.3μg dL–1, indicating some degree of lead toxicity. Incremental lifetime cancer risk (ILCR) assessment showed that up to 2 908 excess cancer cases (102 for Cd, 2 559 for Cr (VI) and 247 for Ni) are likely in Delhi for lifetime inhalation exposure to these species at their current concentrations.

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

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. 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. 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. 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. 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.

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.

Highlights of recent studies and future plans for the French human biomonitoring (HBM) programme

This manuscript presents highlights of recent studies and perspectives from the French human biomonitoring (HBM) programme. Until recently, HBM studies focused on specific populations or pollutants to gain a better understanding of exposure to environmental chemicals, to help regulators reduce environmental exposure and to monitor existing policies on specific concerns. Highlights of recent multicentre biomonitoring studies with specific population or pollutant focus are given. These French HBM studies have been implemented to know: (1) the influence of living near an incinerator on serum dioxin and polychlorinated biphenyl (PCB) levels, (2) the influence of consuming river fish contaminated by PCBs on serum PCBs of fishermen, and (3) the evolution of blood lead levels in children from 1 to 6 years old since 1995. Special emphasis is placed on the use of an integrated (HBM coupled with nutrition and health studies), multipollutant approach. This approach has been initiated in France with a recent national population-based biomonitoring survey, the Etude Nationale Nutrition Santé (ENNS; French Nutrition and Health Survey). This survey will provide the first reference distribution for 42 biomarkers in the French population. The current national HBM strategy will build upon the ENNS and include a national survey of people aged between 6 and 74 years complemented for the neonatal period and childhood by the Etude Longitudinale Française depuis l'Enfance (ELFE; French longitudinal study of children). France also contributes to the harmonization of HBM activities in Europe through participation in European HBM projects.

RESULTS OF AN INTERVENTION STRATEGY TO REDUCE LEAD EXPOSURE IN SUSCEPTIBLE POPULATION GROUPS IN COPSA MICA AREA, ROMANIA

Background and Aims: High levels of lead have entered the environment through human activities such as mining, industrial processes and burning fuels. Studies conducted between 1991 and 2002 focused on lead exposure in children in Copsa Mica area where a primary smelter was processing zinc and lead from mining ores. The results showed an important exposure of the children to lead, impacting somatic development, heme synthesis and neuropsychological development. An intervention program was elaborated and implemented in 2002 in Copsa Mica and blood lead levels (BLL) in children aged 4-15 years were monitored over time to measure the progress along with the intervention. Methods: Data on lead sources, risk factors (playing with soil, putting dirty toys in the mouth, hand washing, cleaning practices etc.), and socio-economic factors were collected using a questionnaire. BLL in children were measured by atomic absorption graphite furnace spectometry. A social marketing program have been implemented in the investigated area. Results: The mean measured BLL decreased between 2002-2009 from 46 μg/dL in 2002 to 22 μg/dL in 2007 and to 16 μg/dL in 2009. Statistically significant correlations were found betwen blood lead levels in children and some behaviours/practices/ attitudes: dirty hands/toys to mouth behaviour, and the use of the vacuum cleaner to clean the house in 2009. Conclusions: In spite of such a major decrease in BLL (three fold) during a relatively short period of time (2002-2009) and taking into account the huge amount of resources which have been allocated to the intervention program, there is still a great need for work to be done on formulating, elaborating and implementing additional measures along with specific indicators to measure the process and progress of intervention at individual level.

SECONDHAND TOBACCO SMOKE: A SOURCE OF LEAD EXPOSURE IN US CHILDREN AND ADOLESCENTS

Background and Aims: Secondhand tobacco smoke (SHS) remains a major source of indoor pollution worldwide. Lead is a tobacco constituent measured in mainstream and sidestream smoke. Our goal was to evaluate the relationship between SHS exposure (number of smokers at home and serum cotinine) and blood lead levels in US children and adolescents who participated in the National Health and Nutrition Examination Survey, 1999-2004. We also evaluated lead dust concentrations as a potential mediator between SHS and blood lead levels. Methods: We analyzed data from 6,830 participants 3 to 19 years of age who were not active smokers and had SHS exposure information and blood lead measurements. We performed linear regression models on log-transformed blood lead levels by serum cotinine quartiles or number of smokers at home adjusted for socio-demographic and household characteristics. Stratified analysis by participant characteristics was used to evaluate the consistency of the findings across categories. Results: Median (interquartile range) blood lead levels were 1.1 (0.8-1.7) µg/dL. After multivariable adjustment, participants in the highest quartile of serum cotinine (≥0.44µg/L) had 28% (95% CI 21, 36%) higher blood lead levels compared to those in the lowest quartile (&lt;0.03 µg/L). Similarly, blood lead levels in children who lived with 1 and ≥2 smokers were 14% and 24% higher, respectively, compared to those living with no smokers. In participants with lead dust information available (3 to 5 years of age), the association between SHS and blood lead levels remained similar before and after adjustment for lead dust concentrations. Conclusions: SHS may contribute to increased blood lead levels in US children. Lead dust does not appear to mediate this association, suggesting inhalation as a major pathway of exposure. Eliminating SHS exposure could reduce lead exposure in children. These findings have important public health implications for lead and SHS prevention programs.

Blood lead levels in children and adolescents in Torreón, Mexico, 1999 - 2009: an age, period, and cohort analysis

Background and Aims: Torreon, a large city in Northern Mexico, is home to the 4th largest lead smelter in the world. Previous studies indicate that children in Torreon are exposed to high levels of...

The potential health risk assessment of lead levels in children's toys

The potential health risk assessment of lead levels in children's toys

Are Lead Risk Questionnaires Adequate Predictors of Blood Lead Levels in Children?

To evaluate the accuracy of the verbal lead risk assessment tool in identifying the presence of measurable blood lead levels (BLL) in children. A retrospective analysis comparing results of a verbal lead risk assessment tool intended to identify elevated BLL in children with actual capillary fingerstick lead screening laboratory data. Three hundred and forty-nine children aged 5 years and younger enrolled in Head Start during the 2008-2009 school year were evaluated. Sixty-nine children had complete data and were included for final analysis. Results of the verbal lead risk assessment and laboratory capillary fingerstick BLL. All 69 children had measurable BLL. The Pass group, 84.3% of the sample, had BLL scores of 2.2±1.5 μg/dl, while the Fail group, 15.7% of the sample, had BLL scores of 1.5±0.65 μg/dl. There was no significant difference in BLL between children that passed the verbal risk assessment and those that failed ( p>.05). The verbal lead risk assessment did not accurately predict measurable BLL in children. Universal BLL screening for children is necessary to identify low levels of lead so that parents and caretakers of children can be notified and assisted in identifying and eliminating sources of lead exposure.

Primary prevention and health outcomes: Treatment of residential lead-based paint hazards and the prevalence of childhood lead poisoning

In order to gain a better understanding of the effects of an investment in primary prevention on health, I investigate the impact of treatment of lead-based paint hazards in housing units (the preventive action) on childhood lead poisoning (the health outcome) at the census tract level in Chicago, IL. I use the findings from the analysis to simulate and then weigh the costs of lead interventions against the potential benefits of reducing blood lead levels in children. Childhood lead poisoning presents an interesting case study of the potential of preventive care in reducing the prevalence of a disease. There is a clear, well-defined pathway of exposure (deteriorating lead paint in older homes) and no method of secondary care that effectively mitigates the negative health effects. I find that a one-tenth percentage point increase in the proportion of older housing units that have been remediated is associated with a four-tenths percentage point reduction in the prevalence of childhood lead poisoning, an elasticity of roughly 0.5. Citywide, this is roughly 2.5 cases of lead poisoning averted for every housing unit remediated. Furthermore, I find evidence that the effect of remediations in preventing the disease has improved over time. The lower bound estimates of the benefits associated with the reduction in lead poisoning – increased expected lifetime earnings and reduced medical expenditures – are two to twenty times the estimated costs of the remediations.

Lead in school drinking water: Canada can and should address this important ongoing exposure source.

Reducing all preventable lead exposures in children should be a public health priority given that blood lead levels in children that were once considered "safe" have since been associated with important neuro-developmental deficits. Limited Canadian data indicate that school drinking water can be an important component of children's overall exposure to lead. Outside of Ontario, however, Canadian schools are not required to test for lead in water; in most of Canada, school testing is case by case, typically initiated by parental concerns. Provinces and territories are encouraged to follow Ontario's example by instituting a routine school water lead testing program in order to identify facilities where action can result in a decrease in students' exposure to lead. Testing and remediation frameworks developed by the US Environmental Protection Agency, Health Canada, and the province of Ontario provide direction to school boards and local and provincial/territorial health authorities.