In the Iron Quadrangle region the public supply of water is done mainly by the impound of water of watersheds. However, in some places, the population use spring water or ground water from closed mines for human consumption. The main natural sources of As in the Iron Quadrangle are related to the rocks that contain lode gold deposits. The antropic sources of As are contaminated refuse piles, soil, and sediment. It was found total As concentration varying from 2 to 2,980 µg/L and As3+ from 1 to 86 µg/L in water samples collected in underground gold mines, artesian wells, and springs in Ouro Preto and Mariana counties. Based on geological and hydrogeochemical studies of the occurrence of As in rocks and groundwater, it was found that the highest As concentrations occurred in aquifers hosted in carbonate sulphide rich rocks. The As monitoring in underground water should be done periodically, independent of its absence in a first instance, in wells and other groundwater caption sources that are used nowadays for public or private suppliers.
arsenic; groundwater; human exposure; gold; Quadrilátero Ferrífero
