A Preliminary Report from a Study on the Environmental Impact of Pyrite Mining and Dressing in a Mountain Stream in Norway

Abstract

The mining, milling and processing of complex zinc and copper pyrite ores causes water pollution in some districts of Norway To determine the effects of the wastewater from the mining and flotation process, and the acid mine drainage from an old, now exhausted pyrite mine, physical, chemical and biological investigations were performed in the Folia river during 1975–1976. The character of the stream is changed primarily by the inflow of sulphate, calcium and heavy metals. In addition to higher concentrations of a number of substances, increased sediment deposition occurs, which is most distinct in the upper regions, downstream from the tailings impoundment. The bottom fauna in the riffles, sampled by a Surber square foot sampler are qualitatively and quantitatively changed. Ephemeroptera, which seem- to give the best picture of the pollution, are investigated at the species level. In this part of the stream the mayfly fauna is represented by 5 families arid 14 species. The impact of mine drainage on the bottom fauna, particularly on the mayflies is discussed in relation to the physico-chemical parameters.