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Lead (Pb) is a toxic heavy metal that is widely distributed throughout the environment. Pb is an important neurotoxic metal and children are more susceptible to its effect due to their higher absorption rate and greater susceptibility of the developing nervous system. In this work, we evaluated the lead exposure levels in children living near a metallurgical plant and identified risk factors associated with its internal dose. All children, aged 1-10 years and 11 months, living near a metallurgical plant in the great Salvador area, Brazil were evaluated in this cross-sectional study and compared with children from a non exposed area. Occipital hair and blood were used to assess exposure. Air lead levels in the respirable fraction (PM(2.5)) were also measured in both areas. Blood lead levels (BLL), hair lead levels (PbH) and air lead were determined by graphite furnace atomic absorption spectrometry. Spearman correlations analysis was used to evaluate correlations between BLL, PbH and descriptors. Significant risk factors were modeled using multivariate linear regression analysis. Air lead levels were approximately ten-folds lower than EPA reference concentration (0.15 μg/m(3)). Median BLL and PbH were 1.65 ± 1.45 μg/dL and 1.26 ± 3.70 μg/g, respectively, in exposed children. In the referents, medians were BLL 1.20 ± 1.20 μg/dL; PbH 2.09 ± 2.06 μg/g. No significant difference was observed in biomarkers levels between boys and girls. It was observed a positive weak correlation (Spearman rho = 0.197, p = 0.033) between BLL and PbH. Our data show that children's lead body burden measured as BLL or PbH are low when compared with the recommended reference values. Despite that, we were able to identify four risk factors associated with increased biological lead levels: age, living near industrial site, environmental tobacco smoking and, above all, domestic waste burning. In order to prevent such avoidable exposure, environmental education and proper waste management should be implemented, especially in developing countries.

Manganese (Mn) is an essential element, but an effective toxic at high concentrations. While there is an extensive literature on occupational exposure, few studies have examined adults and children living near important sources of airborne Mn. The objective of this study was to analyze hair Mn of children living in the vicinity of a ferro-manganese alloy production plant in the Great Salvador region, State of Bahia, Brazil and examine factors that influence this bioindicator of exposure. We examined 109 children in the age range of 1-10 years, living near the plant. Four separate housing areas were identified a priori on the bases of proximity to the emission sources and downwind location. A non-exposed group (n=43) of similar socio-economic status was also evaluated. Mn hair (MnH) concentration was measured by graphite atomic absorption spectrometry (GFAAS). Possible confounding hematological parameters were also assessed. Mean MnH concentration was 15.20 microg/g (1.10-95.50 microg/g) for the exposed children and 1.37 microg/g (0.39-5.58 microg/g) for the non-exposed. For the former, MnH concentrations were 7.95+/-1.40 microg/g (farthest from the plant), 11.81+/-1.11 microg/g (mid-region), 34.43+/-8.66 microg/g (closest to the plant) and 34.22+/-9.15 microg/g (directly downwind). Multiple regression analysis on log transformed MnH concentrations for the exposed children derived a model that explained 36.8% of the variability. In order of importance, area of children's residence, gender (girls>boys) and time of mother's residence in the area at the birth of the child, were significantly associated with MnH. Post hoc analyses indicated two groupings for exposure areas, with those living closest to and downwind of the plant displaying higher MnH concentrations compared to the others. The contribution of the time the mother lived in the community prior to the child's birth to the children's current MnH suggests that in utero exposure may play a role. A study of neurobehavioral performance with respect to Mn exposure in these children is currently underway.