Child neurodevelopment in a Bolivian mining city

Abstract

This study evaluates the neurodevelopment of children living near contaminated mining industries during their first year of life. Participants from the city of Oruro (Bolivia) were prospectively recruited during pregnancy. Follow-up occurred between May 2007 and November 2009. Information about the socioeconomic status and medical history of the pregnant women were collected using questionnaires. Neurodevelopment was evaluated for 246 children using the Bayley Scales of Infant Development (BSID) at 10.5-12.5 months of age. Exposure to trace elements (Pb, As, Cd, Sb, Cs, Zn, Fe, Cu, Se, Rb, and Sr) during prenatal life was evaluated by testing maternal blood concentrations before delivery. Almost all measured levels were lower than the control limits. The blood lead concentration of pregnant women was low, considering the contaminated environmental context. The geometric mean was 1.76 μg/dL (95% CI: 1.68-1.84), a level comparable with those observed in non-contaminated areas. The only element found to be relatively elevated was antimony, with a geometric mean of 1.03 μg/dL (95% CI: 0.96-1.11). Our results suggest that women from this mining area were not highly exposed. The Bayley Scales of Infant Development (BSID) did not reveal mental or psychomotor abnormalities. Surprisingly, at the observed low levels, lead was positively associated with the children's BSID performance.