Determinant Factors of Children's Blood Lead Levels in Java, Indonesia.

INTRODUCTION: Lead poisoning contributes to a significant burden of disease as a toxic substance found in air, soil, and water. In Indonesia, the risk of exposure is high due to the inappropriate recycling of used lead batteries. The objective was to investigate the factors that influence lead levels in children's blood. METHODS: This cross-sectional study assessed blood lead levels (BLLs) in children aged 12-59 months in four communities exposed to used lead-acid batteries (ULABs) recycling activities, comparing them to a control area. The study employed a threshold level of 20 µg/dL to identify high BLLs and utilized a sample size of 324 children from exposed sites and 240 from control sites. Questionnaires, blood lead tests and a home-based assessment for environmental exposures were applied. RESULTS: The study participants comprised 295 boys and 269 girls, with an average age of 35 months. Significant disparities in soil lead concentrations median: Q1-Q3 were found between exposed (6581.7 : 2432.6-16647.1) ppm and control areas (253.5 : 158.8-417.1) ppm. Children in exposed areas had 3.9 times higher odds of BLL ≥20 µg/dL. Fathers with BLL ≥20 µg/dL had children with similarly elevated BLLs. Multivariate analysis identified socioeconomic status, study areas, environmental factors (cookware, food ware, spices, house cleaning), and children's behavior (breastfeeding duration) as determinants of elevated BLLs. Reported environmental factors had notable impact on BLLs, with aluminum cookware (aOR = 1.4, 95%CI [1.2-1.6]), food ware materials (aOR = 1.15, 95%CI [1.0-1.3]), type of spices (aOR = 2.7, 95%CI [1.7-48.0]), and house cleaning method (aOR = 2.9, 95%CI [1.2-7.1]). CONCLUSION: This study highlighted key risk factors affecting children's blood lead levels (BLL) and emphasized the urgency of employing effective strategies to remediate lead-contaminated soils in exposed regions. The findings underscore the need for prompt medical intervention and monitoring for children in these areas, with additional research essential to fully understand lead poisoning pathways in the environment.

Children's lead exposure in the U.S.: Application of a national-scale, probabilistic aggregate model with a focus on residential soil and dust lead (Pb) scenarios.

Lead (Pb) exposures from soil and dust ingestion contribute to children's blood lead levels (BLLs) in the United States. The U.S. Environmental Protection Agency (EPA)'s Strategy to Reduce Lead Exposures and Disparities in U.S. Communities and the Federal Action Plan to Reduce Childhood Lead Exposure describe multi-pronged collaborative approaches. These include reducing multi-media lead exposures nationally using analytical tools such as EPA's Stochastic Human Exposure and Dose Simulation model for lead [SHEDS-Pb; formerly known as SHEDS-IEUBK (Integrated Exposure Uptake Biokinetic model)], which was initially developed and applied with a focus on children's drinking water exposures. In this study we applied SHEDS-Pb to determine what residential soil Pb and dust Pb concentrations (individually and their sum) can keep BLLs of potentially exposed young children in the general U.S. population below specified values, considering aggregate exposures from water, soil, dust, food, and air. We considered two age groups (1 to <2 years and 2 to <6 years), two BLL values (5 µg/dL and 3.5 µg/dL), and two population percentiles (95th and 97.5th). Sensitivity analyses were conducted using several alternative model inputs and data sets, yielding 15 scenarios summarized in the paper. Of those scenarios, we focused on ones with the most recent science and available data. Modeled soil Pb concentrations by age group, population percentile and reference BLL scenarios for the focus scenarios ranged from 70 ppm to 220 ppm; and modeled dust Pb concentrations ranged from 110 ppm to 240 ppm. These results are consistent with current soil and dust Pb concentrations in the U.S. general population and are lower than most of the current U.S. Federal standards. Estimated BLLs compared well with measured BLLs from CDC's NHANES 2009-2016 (0-27 % relative error for focus scenarios). This analysis can be used to inform EPA and other federal Pb efforts.

Exopolysaccharide-producing bacteria enhanced Pb immobilization and influenced the microbiome composition in rhizosphere soil of pakchoi (Brassica chinensis L.).

Lead (Pb) contamination of planting soils is increasingly serious, leading to harmful effects on soil microflora and food safety. Exopolysaccharides (EPSs) are carbohydrate polymers produced and secreted by microorganisms, which are efficient biosorbent materials and has been widely used in wastewater treatment to remove heavy metals. However, the effects and underlying mechanism of EPS-producing marine bacteria on soil metal immobilization, plant growth and health remain unclear. The potential of Pseudoalteromonas agarivorans Hao 2018, a high EPS-producing marine bacterium, to produce EPS in soil filtrate, immobilize Pb, and inhibit its uptake by pakchoi (Brassica chinensis L.) was studied in this work. The effects of strain Hao 2018 on the biomass, quality, and rhizospheric soil bacterial community of pakchoi in Pb-contaminated soil were further investigated. The results showed that Hao 2018 reduced the Pb concentration in soil filtrate (16%-75%), and its EPS production increased in the presence of Pb2+. When compared to the control, Hao 2018 remarkably enhanced pakchoi biomass (10.3%-14.3%), decreased Pb content in edible tissues (14.5%-39.2%) and roots (41.3%-41.9%), and reduced the available Pb content (34.8%-38.1%) in the Pb-contaminated soil. Inoculation with Hao 2018 raised the pH of the soil, the activity of several enzymes (alkaline phosphatase, urease, and dehydrogenase), the nitrogen content (NH4 +-N and NO3 --N), and the pakchoi quality (Vc and soluble protein content), while also raising the relative abundance of bacteria that promote plant growth and immobilize metals, such as Streptomyces and Sphingomonas. In conclusion, Hao 2018 reduced the available Pb in soil and pakchoi Pb absorption by increasing the pH and activity of multiple enzymes and regulating microbiome composition in rhizospheric soil.

The Distribution Characteristics and Potential Risk Assessment of Lead in the Soil of Tieguanyin Tea Plantations in Anxi County, China.

Assessing the distribution and risks associated with the soil lead content in the Tieguanyin tea plantations of Anxi County is critical, given the county's significance as the primary Tieguanyin tea production area in Fujian Province. This study examined the distribution characteristics of soil lead in Anxi County's tea plantations according to the Kriging spatial interpolation of the parameters of the semivariance function of the exponential model. Moreover, the sources of lead content were analyzed, considering geological backgrounds and anthropogenic influences. Ecological risks and the issuance of early warnings were also assessed. The soil lead content in the rocks of the Tieguanyin tea plantations in Anxi County followed the order: andesite > dacite > rhyolite > granite. The soil lead content gradually decreased from the center toward the east and west, forming four distinct north-south parallel zones. High-lead-content areas were identified at the border of Jiandou, Bailai, and Hushang; in the central part of Lutian; and in the southern part of Huqiu. The high levels of soil lead in the tea plantations possibly originated from industrial and mining activities, automobile exhaust, and agricultural activities. The distribution of single-factor pollution indices and potential risk evaluation based on the Soil Environmental Quality Standard, Environmental Technical Conditions for Tea Production Area, and Environmental Technical Conditions for Organic Tea Production Area indicated that the soil in Tieguanyin tea plantations in Anxi County was clean and safe for tea cultivation.

Lead Levels in a Potters Population and Its Association With the Use of Different Glazes: Cross-Sectional Evaluation of the Approved Pottery Program.

Lead is one of the most harmful toxic metals to humans. In Mexico, though most potters still use a lead-based glazing process, a new lead-free glaze has been introduced to the production of pottery. The Approved Pottery Program (APP) promotes the production of lead-free pottery. As a component of the APP, we aimed to document in this pilot study the blood lead levels (BLLs) of a sample of potters and the association with the type of glaze used. A cross-sectional study was conducted based on information from 46 potters grouped by 26 workshops. We measured general sociodemographic characteristics, capillary BLLs, and the lead levels of the dirt floors of the workshops. The evaluation of associations and comparisons between glaze types was performed based on a regression model clustered by workshop. The median BLL measured was 13.6 µg/dl (IQR: 7.8-20.4 µg/dl), and 70% of the BLLs were greater than 10 µg/dl. Workshop managers presented higher BLLs compared to others working in the same workshop (median of 14.1 µg/dl (IQR: 11.6-25.3 µg/dl) versus 10.1 µg/dl (IQR: 5.2-16.7 µg/dl), respectively). The median BLLs of potters who used lead-free glaze in at least 80% of production were 8.8 µg/dl (95% CI: -17.3 to -0.3 µg/dl) lower than the BLLs of those who used lead-free glaze in less than 30% of production, adjusted by workshop role. Additionally, the lead levels were significantly lower in workshop dirt floors where lead-free glaze was used in at least 80% of the production compared to those that use less than 30% (180 versus 916 mg/kg; p < 0.05). The use of lead-free glaze in the production of pottery was associated with both lower BLLs in potters and lower soil lead levels in the workshop area.

One map: Using geospatial analysis to understand lead exposure across humans, animals, and the environment in an urban US city.

Environmental lead contamination negatively impacts human, animal, and ecosystem health, yet there is a lack of research in this area that incorporates a One Health framework - examining co-exposures among species through their shared environment. The purpose of this study was to integrate human and animal data with public soil lead levels to better understand lead exposure patterns across species in an urban US city. Over 200 soil samples were collected, analyzed for lead, and mapped in combination with other risk factors pulled from the literature to identify areas of highest risk. Human socio-demographic data, dog, and house sparrow density data were mapped to investigate the association between these variables and soil lead levels. Geospatial analysis software was used to visualize the geospatial distribution of soil lead levels and known risk factors for environmental lead contamination, and a block group risk score was calculated and mapped. Associations between human and animal-associated variables and soil lead levels and block risk scores were assessed using Spearman's correlations. Positive, statistically significant associations were found between soil lead levels and higher population density, higher education levels, and higher median household income. Areas with higher soil lead levels and lead exposure risk scores were associated with greater dog density and greater house sparrow density. This study fills an important knowledge gap on the risk of environmental lead exposure to humans, domestic animals, and wildlife.

Characteristics and Risk Assessment of Soil Polluted by Lead around Various Metal Mines in China.

The contamination of soil by lead (Pb) is a serious and widespread problem in China, especially in mining areas. This paper summarized the available data regarding Pb-contaminated soils around various metal mines in China. Based on these data, the Pb concentration in the soil and its temporal and spatial changes were analyzed. Potential ecological hazards and adult lead models were also used to estimate ecological and health risks. The results indicated that the concentration of Pb was closely related with the type of mine. Compared with other types of mine, soil around lead-zinc (Pb-Zn) and tin (Sn) mines with high Pb contents in the metallic ores and high pollutant emission coefficient were more strongly polluted by Pb. The characteristic spatial and temporal variations of Pb pollution status in China were clarified, and the results showed that the concentration was high in the southern, southwestern, and central regions of China where many mining areas were located, and the mean value passed a turning point in 2012. Ecological risk assessments indicated that some areas around mines were at considerable to high risk, and the risk was relatively severe in Pb-Zn mining areas. According to the adult lead model, Pb-Zn mines had a greater impact on blood Pb concentration than the other types of mine.

Spatial-temporal association of soil Pb and children's blood Pb in the Detroit Tri-County Area of Michigan (USA).

Lead is a well-known toxicant associated with numerous chronic diseases. Curtailing industrial emissions, leaded paint, lead in food, and banning highway use of leaded gasoline effectively decreased children's exposure. In New Orleans, irrespective of Hurricane Katrina flooding, lead declined concurrently in topsoil and children's blood. We postulate that topsoil lead and blood lead decreases are associated and common in U.S. cities. This study tests that concept. A small 2002 soil lead survey of 8 Detroit Tri-County Area census tracts was repeated in October 2019. Between 2002 and 2019, Detroit median soil lead decreased from 183 to 92 mg/kg (or 5.4 mg/kg/yr.) and declined in Pontiac from 93 to 68 mg/kg (or 1.4 mg/kg/yr.). Median soil lead remained ~10 mg/kg in outlying communities. Median soil lead (in mg/kg) in communities at < 21 km compared to ≥ 21 km from central Detroit, respectively, decreased from 183 to 33 (P-value 10-12) in 2002 and from 92 to 35 (P-value 10-07) in 2019. Children's lead exposures were highest in Detroit (population 0.7 million in 2010) and lower by more than half in Pontiac (population 60 thousand in 2010). Between 2002 and 2018, children with blood lead ≥4.5 µg/dL in Detroit declined from 44% to 5%, and in Pontiac from 17% to 2%. The most vulnerable children live in the most lead contaminated communities. To meet the goal of primary prevention for children, along with other efforts, this study supports landscaping with low lead soil to reduce exposure in lead contaminated communities.

Growth responses and physiological and biochemical changes in five ornamental plants grown in urban lead-contaminated soils.

An increasing concentration of lead (Pb) in urban contaminated soil due to anthropogenic activities has been a global issue threatening human health. The use of urban ornamental plants as phytoremediation of Pb-contaminated soil is a new choice. In the present experiment, the physiological and biochemical response of five ornamental plants to increase in concentrations of C4H6O4Pb·H2O in the soil were measured to investigate these plans' Pb tolerance strategies and abilities. Our results showed that Pb stress significantly inhibited the growth and the biomass of all the plants. The root activity (RA), net photosynthetic rate (P n), and chlorophyll (Chl) content in Pb-stressed leaves were significantly decreased, whereas the leaf proline (Pro), soluble sugar (SS), and membrane stability index (MSI) were remarkable increased compared with those in the control group. By application of all-subsets regression and linear regression, the reduction in photosynthetic capacity in the five plants is mainly due to the decrease in the leaf Chl content caused by Pb stress. The bioconcentration factor (BCF) in Canna generalis was greater than 1, while in the other plants were lower than 1, suggesting that Canna generalis had the highest Pb accumulation ability. The translocation factor (TF) in all the plants were lower than 1, suggesting that Pb preferentially accumulated in the external part of roots. By calculating the comprehensive evaluation value (CEV), Iris germanica L. was found to be the most sensitive species, and Canna generalis was the most tolerant species, to Pb stress among the five ornamental plants.

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.

The State of Public Health Lead Policies: Implications for Urban Health Inequities and Recommendations for Health Equity.

Although lead has been removed from paint and gasoline sold in the U.S., lead exposures persist, with communities of color and residents in urban and low-income areas at greatest risk for exposure. The persistence of and inequities in lead exposures raise questions about the scope and implementation of policies that address lead as a public health concern. To understand the multi-level nature of lead policies, this paper and case study reviews lead policies at the national level, for the state of California, and for Santa Ana, CA, a dense urban city in Southern California. Through a community-academic partnership process, this analysis examines lead exposure pathways represented, the level of intervention (e.g., prevention, remediation), and whether policies address health inequities. Results indicate that most national and state policies focus on establishing hazardous lead exposure levels in settings and consumer products, disclosing lead hazards, and remediating lead paint. Several policies focus on mitigating exposures rather than primary prevention. The persistence of lead exposures indicates the need to identify sustainable solutions to prevent lead exposures in the first place. We close with recommendations to reduce lead exposures across the life course, consider multiple lead exposure pathways, and reduce and eliminate health inequities related to lead.

Improving human health outcomes with a low-cost intervention to reduce exposures from lead acid battery recycling: Dong Mai, Vietnam.

This study details the first comprehensive evaluation of the efficacy of a soil lead mitigation project in Dong Mai village, Vietnam. The village's population had been subject to severe lead poisoning for at least a decade as a result of informal Used Lead Acid Battery (ULAB) recycling. Between July 2013 to February 2015, Pure Earth and the Centre for Environment and Community Development (Hanoi, Vietnam) implemented a multi-faceted environmental and human health intervention. The intervention consisted of a series of institutional and low-cost engineering controls including the capping of lead contaminated surface soils, cleaning of home interiors, an education campaign and the construction of a work-clothes changing and bathing facility. The mitigation project resulted in substantial declines in human and environmental lead levels. Remediated home yard and garden areas decreased from an average surface soil concentration of 3940mg/kg to <100mg/kg. One year after the intervention, blood lead levels in children (<6 years old) were reduced by an average of 67%-from a median of 40.4µg/dL to 13.3µg/dL. The Dong Mai project resulted in significantly decreased environmental and biological lead levels demonstrating that low-cost, rapid and well-coordinated interventions could be readily applied elsewhere to significantly reduce preventable human health harm.

The Association between Environmental Lead Exposure and High School Educational Outcomes in Four Communities in New South Wales, Australia.

The associations between environmental lead exposure and high school educational outcomes in four communities located in New South Wales, Australia, were examined in this ecological study. A mixed model analysis was performed to account for each school's results being more similar than results for other schools. The effect of environmental lead exposure on mean results for five educational outcomes was examined. 'Leaded' schools with more than five per cent of students living in the highest lead risk areas were tested against non-leaded 'comparison' schools that were matched by a pre-defined socio-educational advantage rating. A small disadvantage was found for leaded schools for four out of five outcomes, which was statistically significant for three outcomes: Higher School Certificate English (p < 0.01), School Certificate Mathematics (p < 0.05), and Australian Tertiary Admissions Rank eligibility rate (p < 0.01). This study adds to the large body of evidence in Australia and elsewhere supporting the importance of primary prevention to protect health at multiple stages of development.

Analysis of Pollution Hazard Intensity: A Spatial Epidemiology Case Study of Soil Pb Contamination.

Heavy industrialization has resulted in the contamination of soil by metals from anthropogenic sources in Anniston, Alabama. This situation calls for increased public awareness of the soil contamination issue and better knowledge of the main factors contributing to the potential sources contaminating residential soil. The purpose of this spatial epidemiology research is to describe the effects of physical factors on the concentration of lead (Pb) in soil in Anniston AL, and to determine the socioeconomic and demographic characteristics of those residing in areas with higher soil contamination. Spatial regression models are used to account for spatial dependencies using these explanatory variables. After accounting for covariates and multicollinearity, results of the analysis indicate that lead concentration in soils varies markedly in the vicinity of a specific foundry (Foundry A), and that proximity to railroads explained a significant amount of spatial variation in soil lead concentration. Moreover, elevated soil lead levels were identified as a concern in industrial sites, neighborhoods with a high density of old housing, a high percentage of African American population, and a low percent of occupied housing units. The use of spatial modelling allows for better identification of significant factors that are correlated with soil lead concentrations.

Spatiotemporal dynamic transformations of soil lead and children's blood lead ten years after Hurricane Katrina: New grounds for primary prevention.

BACKGROUND: The contribution of lead contaminated soil to blood lead, especially as it is a large reservoir of lead dust, has been underestimated relative to lead-based paint. On 29 August 2005 Hurricane Katrina flooded and disrupted habitation in New Orleans. Soil and blood lead were mapped prior to Katrina. This unique study addresses soil and blood lead conditions pre- and ten years post-Katrina and considers the effectiveness of low lead soil for lead exposure intervention. OBJECTIVES: Comparison of soil and blood lead levels pre- and ten years post-Katrina to evaluate and assess the impact of flooding on soil and blood lead at the scale of the city of New Orleans. METHODS: Post-Katrina soil and blood lead data were stratified by the same census tracts (n=176) as pre-Katrina data. This unique city scale data-set includes soil lead (n=3314 and 3320, pre- vs. post-Katrina), blood lead (n=39,620 and 17,739, pre- vs. post-Katrina), distance, and changes in percent pre-1940 housing. Statistical analysis entailed permutation procedures and Fisher's Exact Tests. RESULTS: Pre- vs. ten years post-Katrina soil lead median decreased from 280 mg/kg to 132 mg/kg, median blood lead decreased from 5µg/dL to 1.8µg/dL, respectively. Percent pre-1940 housing did not change significantly (P-value=0.674). Soil and blood lead decrease with distance from the center of New Orleans. Except for age-of-housing results, P-values were extremely small (<10(-12)). CONCLUSIONS: Ten years after Katrina, profound changes in soil lead and children's blood lead occurred in New Orleans. Decreasing the lead on soil surfaces reduces children's interaction with lead dust, thus underscoring soil as a major of source of exposure.

Editorial: Lead Risk Assessment and Health Effects.

In 1980, Clair C. Patterson stated: "Sometime in the near future it probably will be shown that the older urban areas of the United States have been rendered more or less uninhabitable by the millions of tons of poisonous industrial lead residues that have accumulated in cities during the past century". We live in the near future about which this quote expressed concern. This special volume of 19 papers explores the status of scientific evidence regarding Dr. Patterson's statement on the habitability of the environments of communities. Authors from 10 countries describe a variety of lead issues in the context of large and small communities, smelter sites, lead industries, lead-based painted houses, and vehicle fuel treated with lead additives dispersed by traffic. These articles represent the microcosm of the larger health issues associated with lead. The challenges of lead risk require a concerted global action for primary prevention.

Bioaccessibility of lead in urban soil of Broken Hill, Australia: A study based on in vitro digestion and the IEUBK model.

This study was conducted to investigate lead (Pb) bioaccessibility in urban soil and to assess health risk to children in the city of Broken Hill, Australia, which was established around one of the world's largest lead-zinc-silver mines. Fifty-three topsoil (0-0.1m) and 50 subsoil (0.3-0.5m) samples were collected from earthen footpaths, nature strips, parks or vacant land throughout the urban area. The soil samples were analysed for total Pb concentration, Pb bioaccessibility and Pb mineral phases, together with important soil physicochemical properties known to influence Pb bioaccessibility. Lead bioaccessibility ranged from 24% to 89% in topsoil and from 16% to 100% in subsoil, exhibiting a generally decreasing pattern with increasing distance from the orebody. Lead bioaccessibility was strongly positively related to total Pb concentration in both the topsoil and subsoil. In subsoil, a moderate negative correlation existed between Pb bioaccessibility and soil pH, while a moderate positive correlation existed between Pb bioaccessibility and soil organic matter (OM) content. In contrast, only a weak positive correlation existed between Pb bioaccessibility and OM content in topsoil. The presence of different Pb mineral phases also appeared to have caused variation in soil Pb bioaccessibility, with galena (PbS)-rich samples tending to exhibit lower Pb bioaccessibility. The prediction of blood lead (PbB) levels in Broken Hill children aged 1-4years using the IEUBK model well matched the measured data from a recent PbB screening, suggesting a high risk of childhood chronic low-level Pb exposure (PbB levels >5µg/dL) in Broken Hill, especially in the vicinity of the orebody. Future Pb abatement programs in Broken Hill should utilise the IEUBK model to establish target soil Pb values in an effort to achieve particular child PbB outcomes.

Use of a Field Portable X-Ray Fluorescence Analyzer for Environmental Exposure Assessment of a Neighborhood in Cairo, Egypt Adjacent to the Site of a Former Secondary Lead Smelter.

The objectives of this study are to demonstrate for the first time the use of a field portable X-Ray Fluorescence Analyzer (XRF) in a multi-media environmental survey and to use the survey results to determine if residual lead from a once-active secondary lead smelter in Cairo, Egypt, still posed a health risk to the residents when comparing results with US EPA standards. Results were analyzed to determine if relationships among the variables indicated that there were residual impacts of the former smelter. Samples collected inside and near a total of 194 dwellings were analyzed. The mean floor dust lead loading was 7.48 µg lead/ft(2). Almost 10% of the dwellings had at least one floor dust wipe sample that exceeded the United States Environmental Protection Agency's (USEPA) interior settled dust lead level of 40 µg lead/ft(2). The median paint lead level was 0.04 mg lead/cm(2). 17% of the dwellings had at least one interior paint sample that exceeded the USEPA standard of 1.0 mg lead/cm(2). Mean soil lead concentration in the study area was 458 ppm and 91 ppm outside the study area. Four of nine composite soil samples exceeded the US EPA limit for bare soil in play areas. Lead concentrations in samples collected in locations outside the study area did not exceed the limit. The highest concentration was in the plot closest to the smelter and may represent residual impact from the former smelter. Statistically significant relationships were not detected between interior floor dust lead loading and either interior paint lead loading or exterior dust lead concentration. Thus, no significant exposure from the former smelter was indicated by these analyses. This may have resulted from the time elapsed since the closing of the smelter and/or the relatively low paint lead levels. Further study is needed in other areas of Egypt near former and active lead smelters. Elevated levels of mercury and arsenic detected in soil samples do not appear to be related to the smelter but warrant further study.

Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid.

Understanding the effects of oxalic acid (OA) on the immobilization of Pb(II) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(II) by KH2PO4, phosphate rock (PR), activated phosphate rock (APR) and synthetic hydroxyapatite (HAP) at different phosphate:Pb (P:Pb) molar ratios (0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or CaCl2, Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after 120 days was reduced by 100% when soils were amended with APR, HAP and HAP+OA, and the TCLP-Pb was <5 mg/L for the red soil at P:Pb molar ratio 4.0. Water-soluble Pb could not be detected and the TCLP-Pb was <5 mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APR was most effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability.

Maternal exposure to neighborhood soil Pb and eclampsia risk in New Orleans, Louisiana (USA): evidence from a natural experiment in flooding.

BACKGROUND: Previous studies link maternal blood lead (Pb) levels and pregnancy-related hypertensive disorders. OBJECTIVE: Assess the relationship between neighborhood soil Pb and maternal eclampsia risk. METHODS: Zip code summarized high density soil survey data of New Orleans collected before and after Hurricanes Katrina and Rita (HKR) were merged with pregnancy outcome data on 75,501 mothers from the Louisiana office of public health. Cross-sectional logistic regression analyses are performed testing the association between pre-HKR accumulation of Pb in soils in thirty-two neighborhoods and eclampsia risk. Then we examine whether measured declines in soil Pb following the flooding of the city resulted in corresponding reductions of eclampsia risk. RESULTS: Cross-sectional analyses show that a one standard deviation increase in soil Pb increases the odds of eclampsia by a factor of 1.48 (95% CI: 1.31, 1.66). Mothers in zip code areas with soil Pb>333 mg/kg were 4.00 (95% CI: 3.00, 5.35) times more likely to experience eclampsia than mothers residing in neighborhoods with soil Pb<50mg/kg. Difference-in-differences analyses capturing the exogenous reduction in soil Pb following the 2005 flooding of New Orleans indicate that mothers residing in zip codes experiencing decrease in soil Pb (-387.9 to -33.6 mg/kg) experienced a significant decline in eclampsia risk (OR=0.619; 95% CI: 0.397, 0.963). CONCLUSIONS: Mothers residing in neighborhoods with high accumulation of Pb in soils are at heightened risk of experiencing eclampsia.