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Relationship between Lead Mining and Blood Lead Levels in Children

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Abstract

The authors studied blood lead levels of 226 randomly selected children, aged 6-92 mo, who lived in either a lead-mining area or a nonmining area, and 69 controls. The authors sought to determine to what extent mining activities contributed to blood lead levels in the children. The mean blood lead levels in the study and control groups were 6.52 microg/dl and 3.43 microg/dl, respectively. The corresponding proportions of children with elevated blood lead levels were 17% and 3%. Soil and dust lead levels were up to 10 times higher in the study than the control group. Elevated blood lead levels appeared to result from exposure to both lead-mining waste and lead-based paint. Mining waste was the cause of the higher prevalence of elevated blood lead levels in these children.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
Copyright © 1998. All rights reserved.
... This pattern could be explained by the high background levels associated with an area of volcanic rock in the east. Moreover, children are potentially more readily exposed to contaminated soil than are adults, owing to their particular diet and behavioral habits [66,67], which contribute to higher HI values. The increased non-cancer risk found in soil in the eastern part of the ...
... This pattern could be explained by the high background levels associated with an area of volcanic rock in the east. Moreover, children are potentially more readily exposed to contaminated soil than are adults, owing to their particular diet and behavioral habits [66,67], which contribute to higher HI values. The increased non-cancer risk found in soil in the eastern part of the study area can be ascribed primarily to the contents of As, Pb, and Cr in natural sources. ...
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... These results indicate that the lead mining caused contamination of the population living in the entire Upper Ribeira Valley region, with the communities of Vila Mota and Capelinha being the most affected, since they live very close to the Panelas mine and the Plumbum refinery. The results of this study are similar to those obtained in studies carried out by Taskinen et al. (1981) and Murgueytio et al. (1998). ...
... In Vila Mota and Capelinha there are no paved roads or streets so the contaminated soils and the soil dust can be significant sources of lead exposure in children (CDC 1991, Murgueytio et al. 1998, Berglund et al. 2000. In this study, it was found that the children in this area usually play outdoors, behavior that increases the possibility of lead absorption, principally due to the natural tendency of children to touch their mouths with their hands when playing. ...
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For several decades, the Ribeira Valley, Brazil, was under the influence of the full activity of Pb-Zn mines and of the Plumbum refinery. Since 1996, all the mines and the refining plant have been closed. The objective of the present study was to assess the exposure of children to lead and to verify the probable sources of human contamination. For the lead exposure study, blood samples were collected from 335 children aged 7 to 14, residing in municipalities around the mines and the refinery. To assess the probable sources of lead exposure, a parallel study of surface water, water from residential taps, stream sediments and surface soils was carried out. The results showed significant correlation between high blood lead levels and the proximity of the residential area to the lead refinery. Lead concentrations in water are consistently low. Stream sediment samples showed elevated lead concentrations, but do not constitute a risk for human exposure because the water pH conditions (pH > 7) prevent the release of lead into the water. Soil samples revealed high lead concentrations, with the highest values found in areas close to the refinery. The highly contaminated soils are considered the main source for human exposure in the Upper Ribeira Valley. 29 than adults. Among residents in lead polluted land, children are more susceptible to absorb the metal present in soil and dust when playing outdoors and because their higher gastrointestinal absorption rates (CDC 1991, Ziegler et al. 1978, WHO 1995, ATSDR 2000). In Brazil, there have been few studies assessing lead exposure among children. The most impressive occurred in Santo Amaro da Purificação, in the state of Bahia, where high levels of lead and toxic effects from that metal were detected among children living close to a lead refinery (Carvalho et al. 1984, 1985, 1995; Tavares et al. 1989, Silvany-Neto et al. 1989, 1996). The present study considered that the population of the Upper Ribeira Valley has been exposed to lead poisoning for decades, both from mining activities and emission of gases and particles into the atmosphere by the Plumbum refinery. Then the possibility that environmental contamination could be affecting people, especially infants, living in the Upper Ribeira Valley was investigated in several municipalities both in urban and rural areas. The ecotoxicological study also included a group of children living in the municipality of Cerro Azul (upstream the mining area in the State of Paraná) making up the reference population for comparison purposes.
... Heavy metals that are formed in fine and light compounds remain suspended in the ambient air and in case of rain, some of these pollutants are dissolved in the rain and return to the earth's surface and some of the heavy metals in the heavy particles are deposited over time and reach the surface of the earth (dust fall particles). In general, the presence of heavy metals in the air or in the dust present in the air increases the concentration of these elements in the body of residents of contaminated areas through ingestion, respiration and skin absorption (8,9). These dust fall particles in addition to polluting the air, are concentrated in the soil after reaching the ground level, and then, the contaminated soils are considered as secondary environmental hazards in two ways: contamination of grains and vegetables and groundwater contamination by the migration of heavy metals from the soil system to the water, especially when the soil is used for agriculture (10). ...
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... However, the number of individuals exposed to metals because of mining activities might be larger if we consider the potential distribution of these elements in the environment. Human exposure to metals has been described at mining sites (42)(43)(44); however, studies of people exposed to metal mixtures at those sites are not easily found in the literature. At a mining site in Mexico (the same site described in Table 2), we have found that 31% of the studied children had lead levels in blood higher than 10 µg/dL, and 71% had urinary arsenic concentrations higher than 50 µg/creatinine (45,46). ...
... There are many miles of unsurfaced roads in rural Missouri mining districts that are responsible for generating large quantities of fugitive dust from vehicle traffic. The concentrations of Pb in this dust are substantially higher than those for non-mining areas and have the potential for being a human health concern especially in young children (Witt et al., 2014;Murgueytio et al., 1998). The proximity of these contaminated dusts to mining, ore processing, and smelting operations suggests that the source is the supporting industry of the region. ...
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Infant exposures to metals are a concern for mining-impacted communities, although limited information is available to assess residential exposures over the first year of life. We measured lead (Pb), manganese, arsenic, and cadmium in indoor air, house dust, yard soil, and tap water from 53 infants' homes near the Tar Creek Superfund Site (Oklahoma, USA) at two time points representing developmental stages before and during initial ambulation (age 0-6 and 6-12 months). We measured infant metal biomarkers in: umbilical cord blood (n=53); 12- (n=43) and 24- (n=22) month blood; and hair at age 12 months (n=39). We evaluated cross-sectional and longitudinal associations between infant residential and biomarker concentrations. A doubling of mean dust Pb concentration was consistently associated with 36-49% higher 12-month blood Pb adjusting for cord blood Pb (P⩽0.05). Adjusted dust concentration explained 29-35% of blood Pb variance, and consistent associations with other media were not observed. Although concentrations in dust and blood were generally low, strong and consistent associations between dust and body burden suggest that house dust in mining-impacted communities may impact children's health. These relationships were observed at a young age, typically before blood Pb levels peak and when children's development may be particularly vulnerable to toxic insult.Journal of Exposure Science and Environmental Epidemiology advance online publication, 9 December 2015; doi:10.1038/jes.2015.76.
... There was a strong relationship between blood lead levels and dust, soil, and paint lead. The authors concluded that soil lead from mining operations played a significant role in children's blood lead levels (Murgueytio et al 1998b). ...
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Chapter
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This book considers how exposure to toxic mixtures affects the different physiological systems and organs, including the respiratory, cardiovascular, immunological, musculoskeletal, nervous and reproductive systems, as well as the various organs, including the kidneys, liver and skin. The author evaluates various sources of exposure, including air, water, and soil pollution; in utero exposure; chemicals contained in foods, cosmetics, and domestic cleaning products; adhesives and paints; industrial chemicals; pesticides; electromagnetic radiation; and chemicals ingested or inhaled during the use of alcohol, tobacco and narcotics. Human Toxicology of Chemical Mixtures also examines the interplay between exposure to these mixtures and the prevalence of various diseases and conditions, including autism, attention deficit hyperactivity disorder (ADHD), developmental neurotoxicology, multiple chemical sensitivity (MSC), chronic fatigue syndrome (CFS), fibromyalgia (FM), Gulf war syndrome, cancer and cancer clusters. The author also discusses how exposure to these mixtures yields the above diseases and conditions in different populations: fetuses, infants, pre-adolescent children, adolescents and adults. Finally, the book addresses the profound policy implications for formulation, labeling and use of chemical products, and it proposes more stringent exposure limits and warning requirements in light of the newly recognized toxic effects that are directly attributable to the mixture of toxic lipophilic and hydrophilic chemicals. * Addresses chemical mixtures, while most literature only deals with single chemicals exposure. * Explains why certain toxicological effects are observed. * Discusses diagnosis and treatment of injuries resulting from exposure. * Explores consequences of effects on product formulation, use, handling and required warnings. * Provides guidelines for safer development of personal care, cosmetic, industrial and consumer use products.
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We identified 24 modern studies of childhood exposures to lead in relation to IQ. From this population, 12 that employed multiple regression analysis with IQ as the dependent variable and lead as the main effect and that controlled for nonlead covariates were selected for a quantitative, integrated review or meta-analysis. The studies were grouped according to type of tissue analyzed for lead. There were 7 blood and 5 tooth lead studies. Within each group, we obtained joint P values by two different methods and average effect sizes as measured by the partial correlation coefficients. We also investigated the sensitivity of the results to any single study. The sample sizes ranged from 75 to 724. The sign of the regression coefficient for lead was negative in 11 of 12 studies. The negative partial r's for lead ranged from -.27 to -.003. The power to find an effect was limited, below 0.6 in 7 of 12 studies. The joint P values for the blood lead studies were less than .0001 for both methods of analysis (95% confidence interval for group partial r, -.15 +/- .05), while for the tooth lead studies they were .0005 and .004, respectively (95% confidence interval for group partial r, -.08 +/- .05). The hypothesis that lead impairs children's IQ at low dose is strongly supported by this quantitative review. The effect is robust to the impact of any single study.
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