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

According to the concentrations of mineral nutrients, the lake is classified as oli- gotrophic. The colour values and the organic matter (3.3 mg/l) and Fe concentrations (average 39 pg/l) are typical of small water bodies in the region. During flood periods in the summer the concentrations of P 0 43- and N03-, which determine the lake productivity, are low. The low micronutrient concentrations of the water entering the water body reflect the low level of chemical weathering of the minerals present in the watershed area. The watershed area of Lake N-254 is 19 km from the “Pechenganickel”smelter, and is ex­ posed to the emission of pollutants. The main pollutants are sulphur compounds and heavy metals (Ni, Cu, Co, etc.). De­ spite the fact that emissions from the smelter dropped to approximately one third of the peak levels of the late 1970s, the deposition of pollutant still has an impact on the water quality. The average concentrations of Cu and Ni are 3.2 (ig/1 and 6.7 |ig/l, respectively. 2.10.2. Lake bottom sediments The sediments in Lake N-254 have relatively high organic matter contents (LOI): in the uppermost 1 cm layer LOI is above 30% (Table 34). As the lake is situated at a distance of 27 km from the Pechenganickel smelter, emissions from the smelter affect the amount of pollution (Ni, Cu, Zn and Co) in the lake. The lake is also subject to pollution by chalcophile elements, such as Cd, Pb and As. The top 2-3 cm sediment layer is the most polluted. The contamination factor values for these toxic heavy metals range from 1.2 to 2.0 (Table 34), i.e. the values correspond to moderate contamination. Zinc has the highest Cfvalue. The contamination factor value for Hg is low. The degree of contamination value (11.5) for this lake corresponds to moderate contamination. Lake Layer, cm LOI Cu Ni Zn Co Cd Pb As Hg cd N-254 0-1 32.69 34 53 89 9 0.44 2.58 1.67 0.022 6-7 34.06 28 36 45 7 0.33 1.63 0.93 0.025 c, 1.2 1.5 2.0 1.3 1.3 1.6 1.8 0.9 11.5 2.10.3. Hydrobiology investigations No direct hydrobiological investigations have been carried out in this lake. Cu, ng/l 32 2.5-3.8 Ni, цд/І 6 1 5.2-8.7 Al, цд/І 16 12-24 Pb, цд/І 03 0.2-0.3 Table 34. The contents oforganic matter (loss of weight on ignition - LOI, %) and heavy metals (цд/д, dry weight) in surface (0-1 cm) and back­ ground (6-7 cm) layers ofsediments. CfandC d - values ofcontamina­ tion factor and degree ofcontamination, respectively. Catalogue o f Lakes in the Russian, Finnish and Norwegian Border Area 97