Catalogue of Lakes in the Russian, Finnish and Norwegian Border Area = [Каталог озер в приграничном районе России, Финляндии и Норвегии] / Nikolay A. Kashulin, Vladimir A. Dauvalter, Sergey S. Sandimirov etc. - Apatity : Institute of the North Industrial Ecology Problems KSC RAS etc., 2008.

Elevated concentrations of P and N are important criteria when estimating water eutrophication.The concentrations of and relationships between species of P and N vary according to the season and the dynamics is to a greater extent determined by the level of production and, consequently, the trophicity of the water body. The average concentrations of total P and total N during the veg etation period are 6 |ig/l and 126 jag/1, respectively. According to the concentrations of mineral nutrients, the lake is classified as oligotrophic. The colour values and or ganic matter (3.4 mg/l) and Fe concen trations (average 24 (ig/1) are typical of small water bodies in the region. During flood periods in the summer the concen trations ofP 0 43‘ and N 0 3“, which deter mine the lake productivity, are low. The low micronutrient concentra tions of the water entering the water body reflect the low level of chemical weathering of the minerals present in the watershed area. Although the water shed of Lake Gardsjoen is relatively dis tant from the “Pechenganickel” smelter, it is still subjected to anthropogenic im pacts. The main pollutants are sulphur compounds 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 has an impact on the water bodies in the region. The average concentrations of Cu and Ni are 2.0 (ig/1 and 4.5 |ig/l, respectively. Hydrochemical properties pH 6.57 6.33-6.71 Electrical conductivity, 36 mS/cm 34-38 Ca, mg/l 1.61 1.50-1.70 Mg, mg/l 0.74 0.78-0.92 Na, mg/l 3.61 3.40-3.83 K, mg/l 0.34 0.32-0.36 HC03, mg/l 37 3.3-4.0 S04, mg/l 4.22 4.04-4.44 Cl, mg/l 5.82 5.34-6.26 Total mineralization, 20.1 mg/l 19.4-20.8 Alkalinity, neq/l 60 54-65 Water colour, deg. 10 8-11 NH4, цд/І 4 1-9 N03, цд/І 3 1-16 Total N, цд/І 108 86-126 po 4, мд/і 1 1-1 Total P, (jg/l 4 1-6 Fe, цд/І 24.2 17.4-35.7 Cu, (jg/l 2Л 1.2-3 .6 Ni, цд/І 4J> 3.7-5.7 Al, цд/І 39 30-48 Pb, цд/І 03 0.2-0.5 2.3.2. Lake bottom sediments The sediments ofLake Gardsjoen have relatively low organic matter contents (LOI) in the uppermost 1 cm layer of slightly more than 20% (Table 26). The lake is located at a distance of only 38 km from the Pechenganickel smelter, and is therefore subjected to the deposition of heavy metals (Ni and Co), as well as chalcophile elements such as Hg, Pb and As. The top 2-4 cm sediment is the most polluted. The accumulation of Pb in the sediments started earlier (Fig. 41). The contamination factor values of these Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea