Pollution Characteristics and Risk Assessment of Potential Toxic Elements in a Tin-polymetallic Mine Area Southwest China: Environmental Implications by Multi-Medium Analysis

A multi-medium system, involving tailing area (tailings, surrounding soils and water) and downstream agricultural area (river water, sediments and farmland soils), was conceived to evaluate the pollution status of potential toxic elements (PTEs, including Fe, Mn, Ni, Cu, Zn, As, Sn, Pb, Cr and Cd) and environmental risks in a tin-polymetallic mine area southwest China. The results indicated that tailings exhibited representative enrichment and combination characteristics of Sn, Cu, Ni, Fe, As, Pb and Cr compared to surrounding soils. Acid mine drainage (AMD) from tailings and other mining-related sources greatly affected river water and farmland soils, resulting in soil acidification and accumulation of Sn, As, Cu and Pb in paddy soils. Overall, potential ecological risks posed by tailings and river sediments, and pollution risks from Cu, As and Pb in farmland should be concerned. Therefore, effective measures should be urgently taken to prevent PTEs and AMD into surrounding environmental media.