The River receives a complex anthropogenic load resulting from:
Assessment of waste matters from Russia side (25% of water catchment) shows that major amount of pollutants coms into the Pasvik River from the Kuetsyarvi (Ni 36 tons/year, P 3.3. tons/year) Sewage waters from smelters and pits also are being dumped in the lake with the Kolosjoki Stream.
The Ni and Cu input from the catchment territory amounts about 10% and does not have a noticeable contribution to the total river pollution.
Water chemistry of the river is stable until mixing with runoff from the Kuetsyarvi. Ni and Cu concentration corresponds to the background values - less then 1 mcg/l. Bat in comparison with water chemistry of the Inari Lake, the P concentration is more than doubled.
An increasing a content of nutrients was found downstream, indicating the river euthrophication. According to the classification on P concentration by Carlson (1991) the trophic status of the middle part of the river was oligo - mesotrophic , lower part mesotrophic. In the lower part of the river a sharp increase in Ni, Cu and also sulphates concentrations was seen.
It results from water income from the heavily polluted Kuetsyarvi.
For the Pasvik River two major ecological problems are distinguished:
- HEP regulations;
- air pollution of the water catchment by the "Pechenganikel" smelter emissions;
- smelter and mine wastes;
- municipal sewage from the settlements on Russian and the Norwegian sides.
Analysis of heavy metals accumulation in the sediments did not show any distinct influence of smelter atmospheric emissions in the river above the inlet from Kuetsyarvi. On the contrary, considerable accumulations of Ni and Cu were noticed below the Kuetsyarvi inlet, a contamination with obviously stems from the "Pechenganikel" company sewage. Concentrations of other metals (Co, Zn, Cd, Pb) were also higher than background values. The Kuetsyarvi receiving the main part of "Pechenganikel" company sewage had maximum Ni, Cu, Hg, Co, Zn concentrations in the surface sediments. Hg did show a deviating pattern of accumulation, being present in the surface sediments of all investigated water localities. In our opinion, this may be caused by processes owing to the regulation of the river (for example, mercury methylation).
According to the Håkanson (1980) index, the upper part of the river system has a moderately degree of contamination, mainly due to the Hg-content (Cd=10.9, CfHg=5.0). The Pasvik River system downstream Kuetsyarvi has considerable Cd values (Cd=22.1), and t he Kuetsyarvi has a very high Cd value Cd=58.7, mainly due to the contribution from Ni and Cu.
Toxicofication by heavy metals. This process is observed in the lower part of the river and is caused by the Ni and Cu input with sewage waters from smelters and pits of the "Pechenganikel" company;
Euthrophication. This process is caused by municipal sewage from the settlements situated within the water catchment and the river regulation.