Sandimirov. S. Pasvik Water Quality Report. Environmental Monitoring Programme in the Norwegian, Finnish and Russian Border Area. Finland, Kuopio: Kopijyva Oy. 2011, №7, p.27-34.

Water Quality in the Lake Kuetsjarvi This report describes the Lake water quality concerning the concentrations of organic matter, nitrogen and phosphorus compounds, principal ions and metals, and shows the diagrams of the distribution of indicators in the lake and the dynamics of their changes. The results confirm the existence of a stable hydro-chemical regime in the lake for over 10 years (2000-2009). Organic matter A sufficiently permanent value of chemical oxygen demand, which varies little across the water area, is characteristic (3,2-7,1 mgl-1) of the Lake Kuetsjarvi. The average content of organic carbon in the study period of 2000 -2009 was 5,0 mgl-1 (Figure 2). No considerable seasonal changes have been found in the content of organic carbon. In the springtime, the TOC, mg/l content of organic carbon is 6,1 mgl-1, while in the summer-autumn period the figure is 4,8 mgl-1. The biggest differences are seen in the receiving area o f Pechenganikel smelter waste water discharges (River Kolosjoki). During the study period, the content o f organic carbon in various years alternately increased and decreased by 1 -2 mgl-1. At present, its content over the entire Lake Kuetsjarvi has increased to reach the 2005 -2007 levels (Figure 2). The colour of water has sufficiently low values (12-36° Pt), making on average 19°Pt. Higher values can be observed in the summertime near River Kolosjoki, Lake Salmijarvi and the lake outlet. Before the commencement of studies in 1990-2000 , the colour of water near Lake Salmijarvi reached an average of 39°Pt. Total phosphorus and phosphates The analysis of data concerning the total phosphorus content in Kuetsjarvi Lake shows that at present, the content of this element corresponds to the natural content across the entire lake (Figure 3). Mg/i 60- 50 40 30 20 2 2 2 Whi t e st one 0 0 0 2 3 0 0 2 "sf Ю 1--- 0 0 0 0 0 0 2 2 2 CO 0 0 2 CD 0 0 2 0 0 0 2 3 0 0 2 2004 2005 2007 2008 CD 0 0 2 0 0 0 2 3 0 0 2 ■'šf Ю 1— CO о о о о о о о о N (N N W CD 0 0 2 Golfsream Salmijarvi Kolosjoki о о о о о о о OJ OJ CM CM OJ см lake outlet P tot PO4 Figure 3. Distribution of total phosphorus and phosphates. Pasvik Water Quality Report | 29