Children's Blood Lead Research Articles

Blood lead in children and associations with trace elements and sociodemographic factors

BackgroundNo safe blood lead concentration in children has been identified. Lead can affect nearly every system in the body and is especially harmful to the developing central nervous system of children.The aim of this study is to analyze blood lead in a population of children and its association with sociodemographic variables, biochemical parameters, copper, iron, selenium and zinc. MethodsWe recruited 155 children (86 boys and 69 girls) with a mean age of 7.3 (SD:4.1). Blood lead and serum selenium concentrations were measured by electrothermal atomic absorption spectrometry. Serum copper and zinc concentrations were measured by flame atomic absorption spectrometry. Serum iron levels were determined by colorimetric assay. A risk exposure questionnaire for lead was administered to the participants. ResultsThe median blood lead level was 1.1 (IQR 0.7–1.6) μg/dL. Regarding risk exposure factors, the youngest children (<2 years) who played outdoors presented a median blood lead concentration of 1.1 μg/dL IQR: 0.48–1.48, compared to the median of 0.3 μg/dL IQR:0.2-0.48 in the children who stated they played at home (p = 0.024). Significant differences were also found when taking into account those parents who smoked (median 1.3 IQR 0.8–1.9 μg/dL vs 0.9 IQR 0.5–1.4 μg/dL of non-smokers, p = 0.002). Children who drank tap water had higher blood lead levels (median 1.2 IQR 0.7–1.6 μg/dL) than those who drank bottled water (median 0.7 IQR 0.2–1.3 μg/dL p = 0.014). In addition, children whose mothers had not finished school had higher blood lead levels (median 1.7 IQR 1.2–2.3 μg/dL) than those whose mothers had finished school (median 1.2 IQR 0.7–1.7 μg/dL) and those whose mothers had gone to university (median 0.9 IQR 0.5–1.4 μg/dL) p = 0.034. In the multivariate lineal regression analysis we continue to observe the association between mother’s higher level of education and lower blood levels (p = 0.04) and the interaction between age and outdoor play (p = 0.0145). ConclusionsIn spite of the decline in blood lead concentrations, associated risk factors continue to exist in vulnerable populations such as children.

Human exposure and risk associated with trace element concentrations in indoor dust from Australian homes

This study examines residential indoor dust from 224 homes in Sydney, Australia for trace element concentrations measured using portable X-ray Fluorescence (pXRF) and their potential risk of harm. Samples were collected as part of a citizen science program involving public participation via collection and submission of vacuum dust samples for analysis of their As, Cr, Cu, Mn, Ni, Pb and Zn concentrations. The upper 95% confidence level of the mean values for 224 samples (sieved to <250 μm) were 20.2 mg/kg As, 99.8 mg/kg Cr, 298 mg/kg Cu, 247 mg/kg Mn, 56.7 mg/kg Ni, 364 mg/kg Pb and 2437 mg/kg Zn. The spatial patterns and variations of the metals indicate high homogeneity across Sydney, but with noticeably higher Pb values in the older areas of the city. Potential hazard levels were assessed using United States Environmental Protection Agency's (US EPA) carcinogenic, non-carcinogenic and Integrated Exposure Uptake Biokinetic (IEUBK) model human health risk assessment tools for children and adults. US EPA hazard indexes (HI) for Cr and Pb were higher than the safe level of 1.0 for children. HI > 1 suggests potential non-carcinogenic health effects. Carcinogenic risks were estimated for As, Cr and Pb whose carcinogenic slope factors (CSF) were available. Only the risk factor for Cr exceeded the US EPA's carcinogenic threshold (1 × 10−4) for children. Children aged 1–2 years had the highest predicted mean child blood lead (PbB) of 4.6 μg/dL, with 19.2% potentially having PbB exceeding 5 μg/dL and 5.80% exceeding 10 μg/dL. The Cr and Pb levels measured in indoor dust therefore pose potentially significant adverse health risks to children.

Association of childhood blood lead levels with firearm violence perpetration and victimization in Milwaukee

Childhood lead exposure impairs future decision-making and may influence criminal behavior, but its role in future firearm violence is unclear. Using public health, education, and criminal justice datasets linked at the individual level, we studied a population-based cohort of all persons born between June 1, 1986 and December 31, 2003 with a valid blood lead test before age 6 years and stable Milwaukee residency (n = 89,129). We estimated associations with firearm violence perpetration (n = 553) and victimization (n = 983) using logistic regression, adjusting for temporal trends, child sex, race, and neighborhood socioeconomic status. Increasing risks for firearm violence perpetration and victimization were found in each higher category of blood lead compared to the lowest, after adjusting for confounding. For perpetration, risk ratios (RR) for increasing comparisons of mean blood lead in categories of ≥5 < 10, ≥10 < 20, and ≥20 μg/dL compared to persons with mean blood lead < 5 μg/dL, were: RR 2.3 (95% CI 1.6, 3.3), RR 2.5 (95% CI 1.7, 3.9), and RR 2.8 (95% CI 1.8, 4.4). For victimization, the same increasing categoric comparisons were: RR 1.8 (95% CI 1.4, 2.3), RR 2.4 (95% CI 1.8, 3.2), RR 3.3 (95% CI 2.4, 4.5). The proportion of firearm violence attributable to blood lead ≥5 μg/dL was 56% for perpetration and 51% for victimization. In Milwaukee, during a period of high lead exposures, childhood levels may have substantially contributed to adult firearm violence. While we cannot definitively conclude causality, the possibility that over half of firearm violence among this sample might be due to lead exposure suggests the potential importance of lead exposure reduction in firearm violence prevention efforts.

The concurrent decline of soil lead and children’s blood lead in New Orleans

Lead (Pb) is extremely toxic and a major cause of chronic diseases worldwide. Pb is associated with health disparities, particularly within low-income populations. In biological systems, Pb mimics calcium and, among other effects, interrupts cell signaling. Furthermore, Pb exposure results in epigenetic changes that affect multigenerational gene expression. Exposure to Pb has decreased through primary prevention, including removal of Pb solder from canned food, regulating lead-based paint, and especially eliminating Pb additives in gasoline. While researchers observe a continuous decline in children's blood lead (BPb), reservoirs of exposure persist in topsoil, which stores the legacy dust from leaded gasoline and other sources. Our surveys of metropolitan New Orleans reveal that median topsoil Pb in communities (n = 274) decreased 44% from 99 mg/kg to 54 mg/kg (P value of 2.09 × 10-08), with a median depletion rate of ∼2.4 mg⋅kg⋅y-1 over 15 y. From 2000 through 2005 to 2011 through 2016, children's BPb declined from 3.6 μg/dL to 1.2 μg/dL or 64% (P value of 2.02 × 10-85), a decrease of ∼0.2 μg⋅dL⋅y-1 during a median of 12 y. Here, we explore the decline of children's BPb by examining a metabolism of cities framework of inputs, transformations, storages, and outputs. Our findings indicate that decreasing Pb in topsoil is an important factor in the continuous decline of children's BPb. Similar reductions are expected in other major US cities. The most contaminated urban communities, usually inhabited by vulnerable populations, require further reductions of topsoil Pb to fulfill primary prevention for the nation's children.

Influence of maternal characteristics on child blood lead levels in selected locations of Kabwe district in Zambia

Influence of maternal characteristics on child blood lead levels in selected locations of Kabwe district in Zambia

Blood Lead Concentrations and Antibody Levels to Measles, Mumps, and Rubella among U.S. Children.

Child blood lead concentrations have been associated with measures of immune dysregulation in nationally representative study samples. However, response to vaccination—often considered the gold standard in immunotoxicity testing—has not been examined in relation to typical background lead concentrations common among U.S. children. The present study estimated the association between blood lead concentrations and antigen-specific antibody levels to measles, mumps, and rubella in a nationally representative sample of 7005 U.S. children aged 6–17 years. Data from the 1999–2004 cycles of the National Health and Nutrition Examination Survey (NHANES) were used. In the adjusted models, children with blood lead concentrations between 1 and 5 µg/dL had an 11% lower anti-measles (95% CI: −16, −5) and a 6% lower anti-mumps antibody level (95% CI: −11, −2) compared to children with blood lead concentrations <1 µg/dL. The odds of a seronegative anti-measles antibody level was approximately two-fold greater for children with blood lead concentrations between 1 and 5 µg/dL compared to children with blood lead concentrations <1 µg/dL (OR = 2.0, 95% CI: 1.4, 3.1). The adverse associations observed in the present study provide further evidence of potential immunosuppression at blood lead concentrations <5 µg/dL, the present Centers for Disease Control and Prevention action level.

Curtailing Lead Aerosols: Effects of Primary Prevention on Declining Soil Lead and Children's Blood Lead in Metropolitan New Orleans.

After decades of accumulation of lead aerosols in cities from additives in gasoline, in 1975 catalytic converters (which are ruined by lead) became mandatory on all new cars. By 1 January 1986 the rapid phase-down banned most lead additives. The study objective is to review temporal changes of environmental lead and children’s blood lead in communities of metropolitan New Orleans. In 2001, a soil lead survey of 287 census tracts of metropolitan New Orleans was completed. In August–September 2005 Hurricanes Katrina and Rita storm surges flooded parts of the city with sediment-loaded water. In April–June 2006, 46/287 (16%) of the original census tracts were selected for resurvey. A third survey of 44/46 (15%) census tracts was completed in 2017. The census tract median soil lead and children’s median blood lead decreased across surveys in both flooded and unflooded areas. By curtailing a major urban source of lead aerosols, children’s lead exposure diminished, lead loading of soil decreased, and topsoil lead declined. Curtailing lead aerosols is essential for primary prevention. For the sake of children’s and ultimately societal health and welfare, the long-term habitability of cities requires terminating all remaining lead aerosols and cleanup of legacy-lead that persists in older inner-city communities.

Status of lead accumulation in agricultural soils across China (1979–2016)

The first national-scale assessment of lead (Pb) contamination in agricultural soils across China was conducted based on >1900 articles published between 1979 and 2016. Pb concentrations, temporal and spatial variations, and influencing factors were analyzed. Children's blood lead levels (BLLs) were also estimated using the integrated exposure uptake biokinetic (IEUBK) model. Pb concentrations in different areas of China varied greatly, which was closely associated with the distribution of Pb-related industries, especially Pb-zinc mine smelting, non-ferrous polymetallic mine smelting, e-waste recycling, and leaded gasoline consumption. The year 2000 was a significant transition year for Pb concentrations, with a rapid increase pre-2000 and a subsequent slow upward trend. Pb concentrations were found to be strongly associated with indicators of economic and social development including gross domestic product (GDP), population size, and vehicle ownership. Leaded gasoline, coal combustion, and non-ferrous smelting were the main sources of atmospheric Pb during the different periods. Predicted BLLs were higher in South China than those in the north. This study details the overall Pb contamination status of agricultural soils in China, and thus provides insights for policymakers with respect to pollution prevention measures.

Prevalence of childhood lead poisoning and respiratory disease associated with lead smelter emissions

BackgroundThe city of Port Pirie in South Australia has been a world leading centre for lead and zinc smelting and processing since 1889 that continues to cause contamination of its environment and resident population. This study quantifies the effect of lead and SO2 emissions from Nyrstar Port Pirie Pty Ltd's smelter on blood lead and respiratory health outcomes, respectively, and establishes what air quality values are required to better protect human health. MethodBlood lead and emergency department presentation data collected by South Australia Health (SA Health) and lead in air and SO2 data collected by the South Australian Environment Protection Authority (SAEPA) were obtained and analysed to quantify health outcomes due to smelter emissions in Port Pirie. Regression analysis was used to assess the relationship between the concentration of lead in air and children's blood lead levels between the years of available data: 2003 to 2017. Ambient SO2 concentrations (SAEPA) measured continuously between 2008 and 2018 were 24-hour averaged and compared to daily local emergency department respiratory presentation rates (available from July 2012 to October 2018). Rates of emergency department respiratory presentations at Port Pirie and regional comparators were calculated as age-standardised rates. ResultsThe data show that increases in ambient SO2 concentrations are associated with increased rates of emergency department respiratory presentations of Port Pirie residents, in which children are over-represented. The 30-day rolling average of respiratory presentations was significantly associated (p < 0.05) with incremental increases in SO2. Analysis of the relationship between lead in air and blood lead shows that annual geometric mean air lead concentrations need to be <0.11 μg/m3 to ensure the geometric mean blood lead of Port Pirie children under 5 years is ≤5 μg/dL. For children aged 24 months, lead in air needs to be no greater than 0.082 μg/m3 (annual geometric mean) to ensure geometric mean blood lead does not exceed 5 μg/dL. ConclusionCurrent smelting emissions continue to pose a clear risk of harm to Port Pirie children. Allowable emissions must be lowered significantly to limit adverse childhood health outcomes including respiratory illness and IQ, academic achievement and socio-behavioural problems that are associated with lead exposure at levels experienced by Port Pirie children. Current SO2 levels are likely to be responsible for increased rates of emergency department respiratory presentations in Port Pirie compared with other South Australian locations. As a minimum, Australian SO2 air quality standards need to be enforced in Port Pirie to better protect human health. Lead in air needs to be approximately 80% lower than the current national standard (0.5 μg/m3) to ensure that the geometric blood lead of children under 5 years is less than or equal to 5 μg/dL.

Early lead exposure and pubertal development in a Mexico City population

BackgroundPrevious studies have examined the association between blood lead levels and pubertal timing in adolescent girls; however, the evidence is lacking on the role of lead exposure during sensitive developmental periods on sexual maturation. ObjectivesTo examine the association of prenatal and early childhood lead exposure with pubertal stages among 264 boys and 283 girls aged 9.8–18.0 years in Mexico City. MethodsWe measured maternal bone lead (a proxy for cumulative fetal exposure to lead from maternal bone stores mobilized during pregnancy) at 1 month postpartum. Blood lead was measured annually from 1 to 4 years. Pubertal stage was assessed by a pediatrician. We examined the association between lead and pubertal stages of breast, pubic hair and genitalia using ordinal regression. Age at menarche was evaluated using Cox proportional-hazard models. ResultsMultivariate models showed that maternal patella lead and early childhood blood lead were inversely associated with breast growth (patella OR = 0.72, 95% CI: 0.51–1.00; blood OR = 0.70, 95% CI: 0.53–0.93) in girls. Girls with maternal patella lead in the 3rd tertile and child blood lead in the 2nd tertile had a later age at menarche compared with girls in the 1st tertile (patella HR = 0.60, 95% CI: 0.41–0.88; blood HR = 0.65, 95% CI 0.46–0.91). Additionally, early childhood blood lead was negatively associated with pubic hair growth (OR = 0.68, 95% CI: 0.51–0.90) in girls. No associations were found in boys. ConclusionsThese data suggest that higher prenatal and early childhood exposure to lead may be associated with delayed pubertal development in girls but not boys. Our findings are consistent with previous analyses and reinforce the reproductive effects of lead for girls.

Environmental injustice and childhood lead exposure in peri-urban (ger) areas of Darkhan and Erdenet, Mongolia

BackgroundThe ger (“tent city”) areas in Mongolia are a product of rapid urbanization and transitional economic development combine with lack of institutional, administrative and financial capacity of governments to cope with the pace. These areas have become traps for inequities in social and environmental services and the associated effects on human health. Disparities in childhood lead exposure in such communities are largely unexplored.MethodsWe measured the concentrations of lead in blood of children, aged 4–7 years, in Erdenet (Orkhon Province) and Darkhan (Darkhan-Uul Province), the second and third largest cities in Mongolia. A survey instrument was used to gather information on influencing factors on lead exposure and the Strengths and Difficulties Questionnaire (SDQ) was used to assess a spectrum of behavioral problems among the children.ResultsThe mean blood lead level (BLL) of children in the two cities was found to be 3.8 ± 2.6 μg/dL (range: < 1.5–17.2 μg/dL) and 27.8% of the children had BLLs ≥5 μg/dL. Average BLL of children in Erdenet (a mining center) was significantly higher than that for children in Darkhan, and there was statistically significant difference between average BLL of children who live in ger district (4.2 ± 2.8 μg/dL) compared to those of children in housing units within the city (3.2 ± 2.4 μg/dL). In spite of the low values, BLLs was significantly associated with a number of effects on the spectrum of behavioral disorders, specifically with the scores for hyperactivity, conduct disorder and pro-social behavior.ConclusionsThis study shows that childhood lead poisoning is common especially in ger communities of the urban areas of Mongolia. It contributes evidence showing that BLL low as 3.8 μg/dL can selectively activate some effects from a spectrum of likely behavioral disorders in children.

Association of Childhood Lead Exposure With Adult Personality Traits and Lifelong Mental Health

Millions of adults now entering middle age were exposed to high levels of lead, a developmental neurotoxin, as children. Although childhood lead exposure has been linked to disrupted behavioral development, the long-term consequences for adult mental and behavioral health have not been fully characterized. To examine whether childhood lead exposure is associated with greater psychopathology across the life course and difficult adult personality traits. This prospective cohort study was based on a population-representative birth cohort of individuals born between April 1, 1972, and March 31, 1973, in Dunedin, New Zealand, the Dunedin Multidisciplinary Health and Development Study. Members were followed up in December 2012 when they were 38 years of age. Data analysis was performed from March 14, 2018, to October 24, 2018. Childhood lead exposure ascertained as blood lead levels measured at 11 years of age. Blood lead levels were unrelated to family socioeconomic status. Primary outcomes were adult mental health disorder symptoms assessed through clinical interview at 18, 21, 26, 32, and 38 years of age and transformed through confirmatory factor analysis into continuous measures of general psychopathology and internalizing, externalizing, and thought disorder symptoms (all standardized to a mean [SD] of 100 [15]) and adult personality assessed through informant report using the Big Five Personality Inventory (assessing neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness) at 26, 32, and 38 years of age (all scores standardized to a mean [SD] of 0 [1]). Hypotheses were formulated after data collection; an analysis plan was posted in advance. Of 1037 original study members, 579 (55.8%) were tested for lead exposure at 11 years of age (311 [53.7%] male). The mean (SD) blood lead level was 11.08 (4.96) μg/dL. After adjusting for study covariates, each 5-μg/dL increase in childhood blood lead level was associated with a 1.34-point increase (95% CI, 0.11-2.57; P = .03) in general psychopathology, driven by internalizing (b = 1.41; 95% CI, 0.19-2.62; P = .02) and thought disorder (b = 1.30; 95% CI, 0.06-2.54; P = .04) symptoms. Each 5-μg/dL increase in childhood blood lead level was also associated with a 0.10-SD increase in neuroticism (95% CI, 0.02-0.08; P = .02), a 0.09-SD decrease in agreeableness (95% CI, -0.18 to -0.01; P = .03), and a 0.14-SD decrease in conscientiousness (95% CI, -0.25 to -0.03; P = .01). There were no statistically significant associations with informant-rated extraversion (b = -0.09; 95% CI, -0.17 to 0.004; P = .06) and openness to experience (b = -0.07; 95% CI, -0.17 to 0.03; P = .15). In this multidecade, longitudinal study of lead-exposed children, higher childhood blood lead level was associated with greater psychopathology across the life course and difficult adult personality traits. Childhood lead exposure may have long-term consequences for adult mental health and personality.

Environmental and socioeconomic factors induced blood lead in children: an investigation from Kashmir, India.

Blood lead toxicity has been prominently related to vehicular emissions. The lead is a carcinogenic metal systematically damages bones and central nervous system. The present investigation is focused on likely impacts of environmental and socioeconomic factors on the concentration of blood lead levels in children. The findings of the study show that the highest blood lead levels were observed in the age group of 4-8years (5.46μg/dl) with mother's education having an inverse proportionality with the blood lead levels of children. Furthermore, children belonging to families with income (> 100,000) exhibited the highest blood lead levels (5.52μg/dl) than the rest of the categories which was further advocated by lower blood lead levels in children residing in better residential conditions. High proximity of school to highway distance seemed to play a vital role in the concentration of lead in children while the traffic flow density was observed to have proportionality effect on the blood lead levels. From the study, it is concluded that 28% of the children in the sample population were having lead levels above the permissible limits as per Centre for Disease Control and Prevention. The study reflects the alarming toxicity of lead in children residing in a non-industrial region which further gives rise to concerns about the health of the children residing in industrialized regions of the world with high lead levels in the environment.

Integrating Childhood and Adult Blood Lead Surveillance to Improve Identification and Intervention Efforts.

The Centers for Disease Control and Prevention (CDC) collects information on blood lead levels (BLLs) in the United States through the Childhood Blood Lead Surveillance (CBLS) system (<16 years of age) and the Adult Blood Lead Epidemiology and Surveillance (ABLES) program (≥16 years of age). While both of these state-based national programs share the mutual goal of monitoring and reducing lead exposure in the US population, blood lead data for children and adults are maintained in separate data collection systems. This limits the ability to fully describe lead exposure in the US population across these 2 distinct population groups from sources such as take-home and maternal-child lead exposure. In addition, at the state level, having a unified system to collect, maintain, and analyze child and adult blood lead data provides a more efficient use of limited resources. Based on feedback from state partners, CDC is working to integrate CBLS and ABLES data collection systems at the national level. Several states have developed or are developing an integrated child and adult blood lead data collection system. We highlight efforts undertaken in Wisconsin, Minnesota, North Carolina, Iowa, and Oregon to investigate workplace and take-home lead exposure. Integrating blood lead surveillance data at the national level will enhance CDC's ability to monitor sources of lead exposure from both the home and work environments including paint, water, soil, dust, consumer products, and lead-related industries. Together, an integrated child and adult blood lead surveillance system will offer a coordinated, comprehensive, and systematic public health approach to the surveillance and monitoring of reported BLLs across the US population.

Heavy metal blood levels and hearing loss in children of West Bengal, India.

Introduction:Heavy metals are a major environmental threat in India and there are several health risks associated with it. The aim of this study was to investigate the relationship between the blood levels of lead, cadmium, arsenic, and mercury and a sensoneurial hearing loss in children aged one to ten years.Method:Heavy metal blood levels were determined using inductively coupled plasma mass spectrometry, with appropriate quality control.Results:We found significantly higher blood lead concentration (mg/L; Mean ± SE) in children with a hearing loss (53.2 ± 4.4) compared to healthy controls (38.4 ± 4.7)/P = 0 0.03/.Conclusion:Children’s blood lead levels ≥ 50 mg/L compared to the levels < 10 mg/L were associated with increased probability of hearing loss (OR, 48.8; 95% CI, 41.9–55.6). The differences in the blood levels of cadmium, arsenic, and mercury between the children with a hearing loss and controls were statistically insignificant (P > 0.05).

Using Medicaid Data to Improve Childhood Lead Poisoning Prevention Program Outcomes and Blood Lead Surveillance.

Wisconsin-specific data revealed that not all Medicaid providers were testing children appropriately for blood lead levels and not all blood lead tests were reported to the Department of Health Services, Childhood Lead Poisoning Prevention Program. The Medicaid program requires blood lead screening for all Medicaid-enrolled children at specific ages. Wisconsin state law requires reporting of all blood lead test results. Projects were implemented to encourage appropriate testing for Medicaid-enrolled children and improve blood lead surveillance. Medicaid billing data were linked to blood lead data to identify Medicaid-enrolled children who had not received the required tests. Medicaid provider report cards were distributed annually from 2006 to 2011 to inform providers of their compliance with federal testing requirements and of the names of children within their practice who had not been tested. Blood lead tests billed to Medicaid but not in the blood lead database were identified and billing providers were contacted to obtain the test report. The number of children tested increased from 81 834 children per year in 2006 to 106 003 children per year in 2010. Testing of Medicaid-enrolled children increased by 31% from 2006 to 2010. The percentage of Medicaid-enrolled children receiving an age-appropriate test increased from 46% in 2004 to a high of 55% in 2010. There were 9035 blood lead tests identified in the Medicaid billing data that had not been reported from 2007 to 2015. There were 468 billing providers who had unreported tests. All sites with unreported tests were contacted, 84% of test results were obtained, and 14% of test records could not be retrieved. Outpatient clinics accounted for the majority of all unreported tests (72%) and irretrievable test records (74%). Childhood lead poisoning prevention programs can effectively utilize Medicaid data to increase testing and improve blood lead surveillance. Primary health care providers should ensure that Medicaid-enrolled children in their care receive the age-appropriate tests. Many Wisconsin health care providers lack awareness of blood lead test reporting requirements. Outpatient clinics account for the largest proportion of unreported tests and highest priority should be given working with these sites to improve reporting practices.

Findings of a Statewide Environmental Lead Inspection Program Targeting Homes of Children With Blood Lead Levels as Low as 5 μg/dL.

There are limited data on the nature of environmental lead hazards identified during residential inspections for child blood lead levels (BLLs) of less than 10 μg/dL. We compare inspection findings for child BLLs of 5 to 9 μg/dL versus 10 μg/dL or more. We reviewed inspection reports in Maine from September 2016 to March 2018. We used continuity-adjusted or Fisher's exact test for categorical variables and Wilcoxon rank-sum tests for continuous variables to compare differences in child, family, household, and lead hazard characteristics between BLL categories (5-9 μg/dL vs ≥10 μg/dL). We used Spearman correlation coefficients to assess relationships between home surface lead dust measurements and BLLs. Of 351 residential inspections, 272 (77%) were for children with BLLs of 5 to 9 μg/dL. Children with BLLs of 5 to 9 μg/dL as compared with children with BLLs of 10 μg/dL or more were less likely to chew window sills and door frames (8% vs 21%; P = .01), but otherwise were similar with respect to other established risk factors for lead poisoning. Children with BLLs of 5 to 9 μg/dL tended to have fewer paint hazards inside their homes (64% vs 78%; P = .03), and they were more likely to have dust-only hazards (8% vs 3%) or no identified lead paint hazards (23% vs 15%), though these differences were not statistically significant. For children with BLLs of 5 to 9 μg/dL, BLL was weakly correlated with average window sill dust level (Spearman r = 0.16; P = .01) and average floor dust level (r = 0.13; P = .03), but these correlations were not observed for children with BLLs of 10 μg/dL and higher. We have found that inspections of homes of children with BLLs of 5 to 9 μg/dL are nearly as likely to identify lead hazards that require abatement as inspections of homes of children with BLLs of 10 μg/dL.

Globally temporal transitions of blood lead levels of preschool children across countries of different categories of Human Development Index

In the past decades, efforts to eliminate lead from gasoline, paint and drinking water around the world have substantially reduced human blood lead levels. This study was therefore aimed at examining the global temporal trends in the blood lead levels of preschool children by the category of UN Human Development Index (HDI). In total, 103 blood lead records were retrieved from 51 articles searched from PubMed and Google Scholar, with study subjects aged up to 8years old. Collected preschool children blood lead levels were plotted chronologically by HDI category and their reciprocals were used in regression analysis against calendar year to establish their temporal transition trends in the past decades. Results show that the modes of blood lead level of the preschool children were reduced from 4–6μg/dL to 0.8–1.5μg/dL, from 6–15μg/dL to 3–6μg/dL and from 12–16 to 5–6μg/dL for the very high HDI countries, the high HDI countries and the medium/low HDI countries, respectively. The highest correlation coefficient, 0.849, between the reciprocal of blood lead level and the calendar year was found for the very high HDI countries. Based on the regression lines, the predicted preschool children mean blood lead levels in the year of 2030 are 0.74μg/dL, 2.21μg/dL and 2.86μg/dL, respectively, for the very high HDI countries, the high HDI countries and the medium/low HDI countries. Persistent differences in blood lead level prevailed among countries of different HDI category, suggesting the effects of disparities and inequalities, at the state level, on preschool children blood lead levels. Further action is warranted to reduce the already low environmental lead exposure to eliminate the developmental burden of lead on children through (1) identification of individual local factors for lead exposure and (2) averting health disparity and inequalities at the state level.

The effect of contemporary mine emissions on children's blood lead levels

BackgroundBroken Hill is home to Australia's oldest silver–zinc–lead mine. However, the precise source of childhood blood lead (PbB) exposures has been subject to considerable debate. Lead sources include natural soil Pb enrichment, legacy deposition, contemporary mining emissions, and Pb-based paint. ObjectiveTo test whether contemporary mining emissions independently affect childhood PbB in Broken Hill. MethodsChildren's (<5 years old) PbB measures from 2011 to 2015 (n = 4852), obtained from Broken Hill Child & Family Health Centre, were analyzed using generalised linear regression models, including covariates of household soil Pb, city dust Pb concentrations (PbD), demographic factors and Pb ore production. Two natural experiments involving wind direction and the 2009 dust storm were examined to test whether the PbB-distance gradient from the mining operations was influenced by contemporary emissions. The influence of contemporary emissions was further interrogated by examining the effect of ore production on PbB and PbD. ResultsChildren living downwind and proximate to the mine had substantially higher PbB outcomes than children similarly distant but upwind. Dust Pb deposition increased significantly with proximity to mining operations as well to Pb production (1991–2013). Average annual PbB correlated with Pb ore production (p < 0.01) with all subsets of children PbB levels responding with near unit elasticity to Pb ore production (p < 0.01). Pre- and post-analysis of the dust storm showed the PbB-distance gradient remained statistically unaltered further confirming contemporary emissions as a source of exposure. ConclusionsContemporary mining emissions influence children's PbB measures independent of other sources and need to be remediated to facilitate reductions in harmful exposure.

Lead Environmental Pollution and Childhood Lead Poisoning at Ban Thi Commune, Bac Kan Province, Vietnam.

Lead poisoning is a public health problem in many areas of the world. Children are at particularly high risk for adverse effects of lead exposure; even at low concentrations, lead can affect physical, mental, and behavioral development. Children living near lead-zinc mines are at high risk for environmental lead poisoning, especially the contaminated soil. We conducted a cross-sectional descriptive study in Ban Thi Commune, northern Vietnam. 195 children (92,9% participation) aged 3-14 years old (average: 7.69 ± 2.90) were randomly selected from a list of all children prepared by the village health collaborators. 109 (55.90%) were boys and 86 (44.10%) were girls. The research measures were the lead concentration in native soil and the children's total blood lead concentration determined by the inductively coupled plasma-mass spectrometry (ICP-MS) method. The results showed that lead content in soil was many times higher than American Environmental Protection Agency and Vietnam standards (average 2980.23 ± 6092.84 mg/kg dry weight of soil (range 80.05 – 33820.62)). Average blood lead levels for children were 15.42 ± 6.45 μg/dL (95% CI: 14.50 -16.33 μg/dL). The percentage of children with lead levels >10 μg/dL (value considered to be lead poisoning for children according to the Ministry of Health of Vietnam) was 79.49% of the total number of children. None of the children in this study had blood lead level (BLL) that required chelation treatment according to Vietnam MOH guideline (BLL ≥45 μg/dL). There is weakly evidence that lead exposure relates to the physical development of children. Children with low lead concentrations (less than 10 μg/dL) had height and weight of 1.47-3.51 cm and 1.19-2.81 kg, greater than those with BLL >10 μg/dL (p>0.05).