Human and environmental contamination in the Iron Quadrangle, Brazil

Arsenic (As) exposure is a potential health risk to local populations around Au mining areas in southeastern Brazil. In April 1998, 126 schoolchildren, aged 9.8±1.12 years in the Minas Gerais mining districts of Nova Lima and Santa Barbara, had their spontaneous urine sampled. Toxicologically low Cd (0.04–0.35 μg L−1, mean 0.13 μg L−1), partly elevated Hg (0.1–16.5 μg L−1, mean 1.1 μg L−1), and generally elevated to high As concentrations (2.2–106 μg L−1, mean 25.7 μg L−1) were found. Twenty per cent of the total sample population showed elevated As concentrations where adverse health effects cannot be excluded on a long-term basis. To assess the potential sources particularly of As, a parallel study of surface waters, sediments, soils, and tailing materials was conducted. While Cd and Hg values were low in all these media, As concentrations in water (0.4–350 μg L−1; mean 30.5 μg L−1), in soils (200–860 mg kg−1), sediments (22–3200 mg kg−1, mean 350 mg kg−1), and tailings (300–21000 mg kg−1; mean 10500 mg kg−1) reveal high concentrations which may lead to an explanation for As pathways in the investigated areas.