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

2.13.1. Hydrochemistry The pH of the water in the lake is neu­ tral, and the water has a low total min­ eralization (average 32.5 mg/l) and al­ kalinity (average 315 |ieq/l). The lake has low concentrations of base cati­ ons and anions, with calcium (average 4.99 mg/l) and bicarbonate (average 19.2 mg/l) predominating. 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 8 |ig/l and 172 |ig/l, respectively. According to the concentrations of mineral nutrients, the lake is classified as oligotrophic. The colour values and the organic matter (4.7 mg/l) and Fe con­ centrations (average 95 |ig/l) are typical of small water bodies in the region. Nickel and Cu are discharged and emiitted from the “Pechenganickel” smelter. The watershed of Lake Stuora- jarve is relatively distant from the Pechenganickel smelter, and the average Cu and Ni concentrations in the water are 1.1 [ig/1 and 0.9 |ag/l, respectively. 2.13.2. Lake bottom sediments Hydrochemical properties pH 6.97 6.79-7.30 Electrical conductivity. 42 mS/cm 31-59 Ca, mg/l 4.99 3.32-6.93 Mg, mg/l 1.55 1.00-2.24 Na, mg/l 1.05 0.83-1.33 K, mg/l 0.44 0.38-0.54 HC03, mg/l 19.2 13.7-23.9 S04, mg/l 4.45 2.42-8.65 Cl, mg/l 0.80 0.59-1.12 Total mineralization, 32.5 mg/l 22.3-44.2 Alkalinity, (aeq/l 315 225-392 Water colour, deg. 19 8-24 NH4, цд/І 15 6-25 N03, ид/1 10 1-22 Total N, |_ig/l 136 113-172 P04, (ig/1 1 1-1 Total P, |ig/l 6 5-8 Fe, pg/l 95 52-130 Cu, |ig/l L I 0.9-1.5 0.9 Ni, |ig/l 0.3-1 .8 37 Al, |ig/l 11-53 Pb, ng/l 02 0.1-0.4 The sediments in Lake Stuorajavre have organic matter contents (LOI) in the uppermost 1 cm layer of less than 20% (Table 37). As the lake is located at a distance of about 300 km from the Pechenganickel smelter, emissions from the smelter have almost no effect on water quality in the lake. However, it is exposed to pollution by chalcophile elements, such as Cd, Pb, As and Hg. The top 2-4 cm sediment layer is the most polluted, with maximum Cd and Pb concentrations in the 1-2 cm layer, maximum As in the uppermost 1 cm layer, and Catalogue ofLakes in the Russian, Finnish and Norwegian BorderArea