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

Fig. 5. Vertical distribution of the concentrations ofNi, Си, Cd and Hg (/ ug/g, dry weight) in the sediment core ofLake LN-2. 1.6.3. Hydrobiological studies The most abundant groups of phytoplankton are diatoms and xantophyta (Sharov, 2004). According to earlier studies (Yakovlev et al., 1991), the lakes close to the “Pechenganikel” smelter have low biodiversity levels. The dominant species are chi- ronomids, water-bugs and beetles. No fish are present in this lake. 1.7. LAKE LN-3. Lake LN-3 (watershed of the River Kolosjoki) is located 14 km to the east of the town of Nikel, and 9 km to the west of the town of Zapolyarny. It is a small (area of the lake 0.05 km2), shallow-water (maximum depth 7 m) round lake of glacial origin. The maximum length is 440 m, and maximum width 180 m.The point of maximum depth (7 m) is located in the central part of the lake. According to the landscape type, the watershed area belongs to the tundra zone with heights extending up to 320 m. The lake shores are not high and are rocky. The water of the lake is colourless. Boulder beds are present in almost all parts of the littoral zone, and extend down to a depth of about 2-2.5 m.The gaps between the boulders are filled with pebbles. 1.7.1. Hydrochemistry The lake is one ofthe most polluted lakes in the Pechenga area, due to its vicinity to the “Pechenganikel”smelter. Airborne industrial pollution has a major impact on the water quality. The water of the lake is neutral and the mean total mineralization 29.5 mg/l and mean alkalinity 109 peq/1. During flood periods the pH of the water falls to 6.56 and then rises back to 6.99, i.e. oxidation processes do not develop due to the buffering capacity of the water. The lake has high concentrations o f base cations and anions, calcium (average 4.8 mg/l) and sulphate (average 10.1mg/l) predominating. Physico-geographical characteristics Watershed River Kolosjoki— Lake Kuetsjarv— River Paz Latitude 69°26.224' Longitude 30°34.911' Height above sea level, m 280.0 Maximum length, km 0.44 Maximum width, km 0.18 Maximum depth, m 7 Area, m2 0.05 Watershed area, km2 0.61 Study period 2003-2007 Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea 27