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

Sediment dating has been carried out on the cores. Pollution by Ni, Cu and Co, i.e. heavy metals emitted into the atmosphere by the Pechenganikel smelter, started in the beginning of the 20th century. Pollution by chalcophile elements started at the end of the 19th century, and was primarily due to long-range, airborne transport from indus­ trial sources in Western Europe. It increased considerably at the beginning of the 20th century, and was connected with the start of activities at the “Pechenganikel”smelter. The contamination factor values for these toxic elements range from 2.7 to 14.9 (Table 20), i.e. the values correspond to considerable and high contamination. Lead has the highest Cfvalue. The degree of contamination value (51.7) for this lake corresponds to high contamination, and this is one of the highest values among the studied lakes. 1.18.3. Hydrobiological studies H yd rob iologica l ind ices 30 species of phytoplankton were registered in lake Shuonijaur, the most numerous species being diatoms, cyanobacteriae and yellow-green algae (Kashulin, 2004). The species composition of the ground fauna of the River Sgunijoki, which flows out of Lake Shuonijaur, consists of about 25 species. The zoobenthos consists of chironomids, dayflies, caddis flies and stone flies (Yakovlev et al., 1991). Ichthyofauna. Studies on the fish community of Lake Kuetsjarvi were conducted in 1992 and in 2005. According to these studies, the ichthyofauna of the lake consists of five species belonging to four fish families: arctic char ( Salvelinus alpinus ), trout ( Salmo trutta), perch ( Perea fluviatilis), burbot ( Lota lota) and nine-spine stickleback ( Pun gitiu spun - gitius). Ovewrall, trout and arctic char are predominant in the lake (Fig. 26). Perch is not so common. Burbot is occasionally caught, and nine-spine stickleback inhabits the Catalogue o f Lakes in the Russian, Finnish and Norwegian Border Area 63