| Summary: | For the Pasvik River watercourse two major ecological problems was encountered: 1) Effects of heavy metals. This process is observed especially in Keutsyarv and to a lesser extent in lower part of Pasvik River. This is caused by the Ni and Cu input with waste water from smelters and pits of the "Pechenhanickel" company. Very high content of heavy metals (especially Ni) in water, lake sediment, macrophytes and fish is documented in Kuetsyarv. Extensive toxic effects were documented on the fish-population in the lake. The toxic effects are less than expected from the concentrations of heavy metals. This is due to high calsiumcontent, organic matter and eutrophication. 2) Eutrophication. This process is caused by domestic sewage from the settlements and compostion of planctonic and benthic communities, Kuetsyarv is eutrophic and the Pasvik River is oligotrophic to oligo-mesotrophic. Norwegian Ministry of Environment Miljøverndepartementet (MD)
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