Iron speciation in acid mine effluents: chemical and microbial controls

The Black Fork Creek watershed, located in Perry and Morgan Counties, Ohio, was selected as a representative field site for evaluating the solution chemistry of iron in streams receiving acid coal mine drainage. Water samples from a point source of acid discharge and a 2 km downstream section of the receiving stream were examined in detail. The total sulfate content, total iron content, Eh and pH of the acid effluent were 4500 micro-g/ml, 1250 micro-g/ml, + 584 mV and 2.9, respectively, at the time of sampling. Ferrous iron accounted for 95% of the total iron load.