The specific objectives of this study were: (1) to establish background content levels of potentially harmful elements in topsoil of Quintero and Puchuncavi districts; (2) to assess the degree of topsoil pollution and identify the local sources of pollution; and (3) to assess the health risk of metal exposure to population. Data from a Chilean Environmental Ministry report were analyzed. Multivariate analysis suggests that the potentially harmful elements are split into two main groups, which can be explained by controlling geogenic (Ni, V and Zn) and anthropogenic (As, Cd, Cu and Pb) factors. The spatial distribution of As, Cd, Cu and Pb displays a spatial pattern around the Puchuncavi-Ventanas industrial park. The background values determined with MAD (median absolute deviation) method include As 31.6 mg kg-1, Cd 0.7 mg kg-1, Cu 296 mg kg-1, Ni 16.9 mg kg-1, Pb 48.6 mg kg-1, V 199 mg kg-1 and Zn 192 mg kg-1. The pollution indices reported considerable contamination to very high contamination in some soil samples. Hazard quotient values were higher for children than for adults, due to the ingestion and dermal absorption, while the cancer risk index values were in the acceptable range.
Keywords: Background range; Compositional data; Ecological indices; Health risk assessment; Potential harmful elements; Urban soils.