Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

Elevated concentrations of P and N are important criteria when estimating water eutrophication.The concentrations of and relationships between species ofP and N vary according to the season and the dynamics is to a greater extent de­ termined by the level of production and, consequently, the trophicity of the water body. The maximum concentrations of total P and total N during the vegeta­ tion period are 5 pg/l and 188 pg/l, respectively. According to the concentrations of mineral nutrients, the lake is classified as oligotrophic. The colour values and the organic matter (4.2 mg/l) and Fe con­ centrations (average 20.7 pg/l) are typi­ cal of small water bodies in the region. During flood periods in the summer the concentrations ofP 0 43' and N 0 3~,which determine the lake productivity, are low. The watershed of Lake Skrukkevatn is subjected to severe anthropogenic im­ pacts from the “Pechenganickel”smelter. The main pollutants are sulphur com­ pounds and heavy metals (Ni, Cu, Co etc.). Despite the fact that emissions from the smelter have been reduced to approximately one third of the maxi­ mum levels of the late 1970s, the depo­ sition of pollutants still influences the water bodies in the area. The average concentrations of Cu and Ni are 4.3 pg/l and 7.2 pg/l, respectively. Hydrochemical properties pH 6.66 6.61-6.72 Electrical conductivity, mS/cm 34 34-35 Ca, mg/l 2.29 2.25-2.34 Mg, mg/l 0.72 0.71-0.75 Na, mg/l 2.80 2.77-2.88 K, mg/l 0.37 0.37-0.38 HC03, mg/l fLO 4.9-5.1 S04, mg/l 4.16 4.05-4.22 Cl, mg/l 4.39 4.36-4.45 Total mineralization, mg/l 19.8 19.5-20.1 Alkalinity, (jeq/l 82 81-84 Water colour, deg. 14 14-14 NH4, pg/l 6 4-8 N03, цд/І 12 2-18 Total N, ng/l 142 116-188 P04, мд/і 1 1-1 Total P, цд/І 4 3-5 Fe, цд/І 20.7 10.6-41.0 Cu, цд/І 43 3.6-4.9 Ni, цд/І Z 2 6 . 8 - 8.0 Al, |ag/l 51 38-75 Pb, цд/І 0 2 0.2-0.3 2.12.2. Lake bottom sediments The sediments in Lake Skrukkevatn have relatively low organic matter contents (LOI) : in the uppermost 1 cm layer LOI is about 20% (Table 36). As the lake is situated at a distance of only 18 km from the Pechenganickel smelter, emissions have a considerable effect on pollution (Ni and Co) levels in the lake, and the lake is also subjected to pollution by chalcophile elements, such as Hg, Pb and As. The top 2-3 cm layer is the most polluted (Fig. 49). The contamination factor values for these heavy metals range from 1.5 to 6.6 (Table 1), i.e. the values correspond to moderate and high (Co and Pb) contamination. Cobolt has the highest Cfvalue. The contamination fac­ tor values for the other heavy metals are low. The degree of contamination value (20.7) calculated for the lake corresponds to considerable contamination. Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea