Arsenic contamination, speciation and environmental consequences in the Bolivian plateau

There are no comprehensive studies of geogenic arsenic (As) contamination of water resources and its human impact in Bolivia. A few studies have been conducted in the historic mining areas of the Bolivian plateau, where acid water drainage (locally known as copagira) from active and abandoned sites has caused extensive contamination of rivers and soils. This chapter describes As and heavy metal contamination of surface water, groundwater and soils in the Poopó and Uru Uru basins and the Uyuni salt pan in western Bolivia, which are generally attributed to past mining of silver and gold associated with sulfides of Fe, Cu, Cd, Zn, Pb, As and Co. Concentrations of As and Cd at the sites close to mining areas are much higher than in reference areas. Without exception, the rivers that drain mining areas into Poopó lake are chemically contaminated. Some rivers are acid, with a pH of around 3, and polluted with heavy metals and As at concentrations 10 to 100 times aboveWHOguidelines. Such concentration ranges are also observed in the suspended solid concentrations