A geochemical approach was applied to understand the factors controlling the mobilization of As and trace elements (TEs) in these mining areas. A total of 30 samples (wells and geothermal water) were collected during the rainy season (2009). As, Cd and Mn concentrations exceed WHO drinking guidelines in some groundwater samples, but Cu, Ni, Pb and Zn do not. Factor analysis of the groundwater chemical data suggests the following geochemical processes: i) plagioclase weathering, ii) dissolution of gypsum and halite, iii) trace element mobilization at acidic pH, iv) sulfide oxidation, and v) release of As following competition with phosphate and bicarbonate for adsorption sites. The As and TEs mobilized in these regions could affect the local water sources, which is a prevalent concern with respect to water resource management in this semi-arid Altiplano region.