Elemental characterization of superficial waters contaminated by an abandoned sulfide-mining area, through neutron activation analysis

Abstract

In this work, superficial waters of two small rivers flowing in the São Domingos' abandoned mining area were analyzed in order to infer on soil-water transfer of the elements determined. Instrumental neutron activation analysis was used for elemental concentration assessment. The following elements were found at the mg L−1 level: As, Ba, Co, Cu, Fe, K, Na and Zn. The dry-mass residues varied between 70 mg and 1 g in 20-mL volumes. High enrichment relative to soil was found for most elements. Good statistical associations between Br and Na, between Cr and Sc, and between Ce, Co, Fe, Yb, and Zn, were found, suggesting a similar mechanism of soil-water, elemental transfer. Both the superficial waters' composition and their elemental levels indicate a potential risk of contamination of the underground waters and an actual health risk for the resident populations.