Natural heavy-metal release by sulphide oxidation in the High Arctic

An assessment of the environmental impact of the weathering of sulphide-ric h rocks at Citronen Fjord, North Greenland, provided information on sulphid e oxidation rates and metal release from outcrops of sediment-hosted, strat iform ore that may be mined for its zinc content. In situ oxygen uptake rat es were measured at the surface of partly weathered sulphide-rich outcrops and compared with metal contents in streams and soil water. The oxygen upta ke rates measured during August 1996 were of the same order of magnitude as those reported from mine tailings at lower latitudes. The variation in met al concentrations and pH of the drainage waters reflects the spatial variat ion in sulphide oxidation and carbonate buffering. High weathering rates of sulphide minerals occur in the High Arctic during the summer, and release of heavy metals must be considered a potential environmental issue if minin g is initiated.