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

1.4.1. Hydrochemistry The water of the lake is neutral and is characterized by low total mineralization values (average 27.8 mg/l) and low alkalinity (average 135 |ieq/l).The lake has low concentra­ tions of base cations and anions, sodium (average 4.24 mg/l) and bicarbonate (average 8.2 mg/l) predominating. Based on the concentrations of mineral nutrients, the lake is classified as oligo- trophic. The concentrations of total P are 6 [ig/1, and of total N 112 |ig/l. The lake also has colour values, organic matter concentrations (up to 5.2 mg/l) and Fe concentrations (mean 47 |ig/l) typical of small water bodies in this region. Dur­ ing high water periods and high precipi­ tation events in the autumn, the concen­ trations of mineral nutrients (P 0 43 and N 0 3) that determine the lake produc­ tivity are low The water exchange index is 1.1, i.e. full water exchange in the lake takes about one year. The watershed area of the lake Kiriko- vanjarvi is subjected to anthropogenic impacts from the smelter. The main pollutants are sulphur compounds and heavymetals (Ni. Cu, Co etc.). In spite of the fact that emissions from the smelter have been reduced to approximately one third of the peak levels in the late 1970s, the deposition of pollutants still has an impact on the water body Copper (up to 4.3 [ig/1) and Ni (up to 11.3 |ig/l) con­ centrations in the vicinity of the smelter are substantially higher than in other parts of the region. 1.4.2. Lake bottom sediments The sediments ofLake Kirikovanjarvi are characterized by relatively low organic matter contents, with LOI values in the uppermost 1 cm layer of slightly more than 20% (Table 4). The lake is situated at a distance of 18 km from the smelter, and is exposed to significant atmospheric impacts of emissions from the smelter. This is reflected in the increased concentrations of heavy metals (Ni, Cu, Co), and chalcophile elements (Pb, As, Cd and Hg). The top Hydrochemical properties pH 6.99 6.98-6.99 Electrical conductivity, mS/cm 46 46-46 Ca, mg/l 2.36 2.25-2.47 Mg, mg/l 1.25 1.24-1.26 Na, mg/l 4.24 4.24-4.24 K, mg/l 0.58 0.57-0.58 HC03, mg/l 8 2 8.2-8.2 S04, mg/l 4.86 4.79-4.83 Cl, mg/l 63 6.2-6.3 Total mineralization, mg/l 27.8 27.6-28.0 Alkalinity, neq/l 135 135-135 Water colour, deg. 19 19-19 NH4, цд/І 5 2-9 N03, цд/І 2 1-2 Total N, цд/І 92 65-119 P04, |ig/l 1 1-1 Total P, цд/І 6 6-6 Fe, цд/І 47 45-50 Cu, |ig/l 4J_ 4.0-4.3 Ni, |ig/l 10.6 10.0-11.3 Al, ng/l 43 39-48 Pb, |ig/l 0.14 0.13-0.21 Catalogue o f Lakes in the Russian, Finnish and Norwegian Border Area