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

dwarf arctic birch and dwarf shrubs oc­ cur in places.The bogginess coefficient is 14.8%. The water of the lake is colourless but, during high precipitation episodes in the summer, the colour of water in­ creases to 32 deg. and becomes slightly yellowish. Boulder beds occur in almost all parts of the littoral zone, and extend down to a depth of about 2-2.5 m. The gaps be­ tween the boulders are filled with peb­ bles. Dark green silt deposits are pre­ dominant at a depth of ca. 2-3 m. 1.16.1. Hydrochemistry The water of the lake is neutral, close to the oxidation point; it is characterized by low total mineralization (average 22.4 mg/l) and alkalinity (average 212 peq/1). During flood pe­ riods the pH of the water falls to 6.88 and then rises back to 7.13, i.e. oxida­ tion processes do not develop due to the buffering capacity of the water. The lake has low concentrations of base cations and anions, with calcium (average 2.92 mg/l) and bicarbonate (average 12.9 mg/l) predominating. Intensive pollution of the lake oc­ curred during the period of peak emis­ sions from the Pechenganikel smelter in the late 1980s and early 1990s. At that time there were maximum concentrations of most elements, especially sulphate (up to 6.4 mg/l), Cu and Ni. At the present time, however, the concentrations of these ele­ ments, as well as of other elements that characterize the sate of the water body, are lower. The annual chemical cycle of the lake is characterized by a reduction in total miner­ alization to 20 mg/l, an increase in the oxidizability and a drop in pH during the flood period and when high precipitation episodes result in an increased inflow of humic water into the lake. During low-water periods, which mainly occur in winter and au­ tumn, and when the inflow ofgroundwater increases, the total mineralization increases slightly to 31.3 mg/l, the oxidizability is reduced and the pH rises. The P and N concentrations ofwater are the main criteria used in assessing the de­ velopment of water eutrophication. The concentrations and relationships between the species of these mineral nutrients vary according to the season, and the dynamics is to a greater extent determined by the level ofproduction and, consequently, the trophicity of the water body. The highest total P concentration in the lake (up to 12 |ag/l) typi­ cally occurs in the summer, when it is 3 times higher than the concentrations during the flood period. The highest total N concentrations (up to 256 |ig/l) occur during the Physico-geographical characteristics Watershed River Madsash— River Lotta Latitude 68°35.853' Longitude 28°40.250' Height above sea level, m 133.1 Maximum length, km 5.6 Maximum width, km 1.0 Maximum depth, m 8 Area, m 2 3.2 Watershed area, km 2 27.5 Study period 1989-2007 Hydrochemical properties pH 7.08 6.88-7.29 Electrical conductivity, mS/cm 30 28-41 Ca, mg/l 2.92 2.69-3.63 Mg, mg/l 1.02 0.89-1.35 Na, mg/l 1.39 1.26-1.88 K, mg/l 0.43 0.37-0.58 HC03, mg/l 12.9 11.8-16.5 S04, mg/l 2.75 2.04-6.40 Cl, mg/l 1.10 0.80-2.10 Total mineralization, mg/l 22.4 20.0-31.3 Alkalinity, |jeq/l 212 193-270 Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea