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 mu g L-1, mean 0.13 mu g L-1), partly elevated Hg (0.1-16.5 mu g L-1, mean 1.1 mu g L-1), and generally elevated to high As concentrations (2.2-106 mu g L-1, mean 25.7 mu g 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 ill all these media, As concentrations in water (0.4-350 mu g L-1; mean 30.5 mu g 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 2kg(-1)) reveal high concentrations which may lead to an explanation for As pathways in the investigated areas. (C) 1999 Elsevier Science Ltd. All rights reserved.