Heavy metal pollution and health risk assessment of soils from open dumps in the Metropolitan Area of Buenos Aires, Argentina

Abstract

We assessed heavy metal pollution and potential health risk by ingestion of soil in six open dumps in the Metropolitan Area of Buenos Aires (MABA), Argentina. For the determination of Cd, Cu, Ni, Pb, Zn, Hg, and Cr, soil samples were taken from the first 10 cm using sampling grids installed between the boundaries of the waste final disposal sites and the beginning of the urban area. Soil samples were considered contaminated if at least one metal exceeded the maximum levels established by the Argentine regulation. Potential health risk by soil ingestion was calculated using deterministic analysis for both adults and children and stochastic analysis only for children. In 39.8% (N = 171) of the soil samples, the concentration of at least one metal was above the guide levels. Concentrations of Pb, Cu, and Zn exceeded maximum permissible values in all open dumps. Except for Hg, heavy metal concentrations differed significantly among open dumps. Hazard indexes > 1 were obtained for the children's population using both deterministic and stochastic models. The most sensitive variables in the stochastic model were exposure frequency and soil ingestion rate, together explaining 70% of the variation in the forecasts. The calculated risks were highly dependent on Pb concentrations. The determination of blood lead concentration in children and the assessment of other exposure routes are needed in areas of open dump influence in MABA.

Keywords: Health risk; Heavy metal pollution; Metropolitan Area of Buenos Aires; Open dumps; Urban soil; Waste.