Preliminary assessment of potential pollution risks in soils: case study of the Corrego do Feijao Mine dam failure (Brumadinho, Minas Gerais, Brazil)

The magnitude of the impacts caused by tailing dam failures represents, in a very short space of time, the potential risks of metals on the environment along time. In riparian soils affected by the failure of Corrego do Feijao Mine dam (Brazil), potential pollution risks were estimated using geochemical indices. Based on background and baseline values, strong anthropogenic interferences in the soil metal enrichment has been evidenced after collapse. Abnormal levels of Cd (1.01 mg kg(-1)), Cr (80 mg kg(-1)), As (28 mg kg(-1)), Cu (90 mg kg(-1)), Pb (80 mg kg(-1)), and Ni (35 mg kg(-1)) in soils were associated to the highest risks. Overall, the potential ecological risk (>600) and pollution load (>5) indices indicated Brumadinho, Mario Campos, Betim and Sao Joaquim de Bicas as the areas most affected by the tailings spill. For the most areas, the geological accumulation index calculated from baseline values showed high commitments in soil quality, with pollution degree from moderately to strongly polluted (from 3 to 5, for Hg and Ni) and extremely polluted (>5, for Cd and Pb). In order to maintain the functional ecosystem integrity, restorative and reparative actions must be urgently carried out in these areas