PAH content in acid drainage mine (ADM) brazilian effluent.

In Santa Catarina area (southern Brazil) coal mining process was a very important activity, which has carried out many environmental problems. Sulphate oxidation produces acid mine drainage (AMD), which is the major pollution causes referring to water basin because of its low value of pH, high content of heavy metals (HM) and sulphates, and potential presence of polycyclic aromatic hydrocarbons (PAH). In order to verify an eventual impact of those substances on environment, toxicity assays with Daphnia magna were performed using AMD effluent before (in nature) and after (treated) treatment using neutralization followed by flotation by dissolved air (FDA). Daphnia magna mortality acute (24 h) test showed toxicity until 64 (in nature) and 16 (treated) AMD effluent dilution. The obtained results support evidence that it don’t exist relation between treated effluent HM content and bioassay toxicity response, both as single and as mixture tested HM, i.e. without synergic or additive effects. MS-GC analysis reveals maximum PAH value of 3 g L-1 into corresponding effluent sediment. We suppose that PAH content might be responsible for toxicity unexplained.