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

that emissions from the smelter have dropped to approximately one third of the peak levels of the late 1970s, the deposition of pollutants still has an impact on the water bodies in the area. The average concentrations of Cu and Ni are 1.8 |ag/l and 5.8 |ag/l, respectively. 2.8.2. Lake bottom sediments The sediments of Lake Kobbholmvatn have extremely low organic matter contents (LOI): in the uppermost 1 cm layer it is only slightly more than 3% (Table 32). Owing to the fact that the lake is situated at a distance of 34 km from the smelter, the depo­ sition of pollutants has only a minor effect on water quality. Pollution by chalcophile elements is also relatively insignificant. The contamination factor values for the heavy metals range from 0.5 to 1.1 (Table 32), i.e. almost all the metals, apart from Ni, have low contamination levels. The degree of contamination value (5.2) for this lake cor­ responds to low contamination. Lake Layer, cm LOI Cu NI Zn Co Cd Pb As Hq Kobbholmvatn 0-1 3.45 74 67 107 27 0.13 16.0 1.35 0.022 14-15 13.13 130 60 197 61 0.22 33.5 1.53 0.037 c, 0.6 1.1 0.5 0.5 0.6 0.5 0.9 0.6 5.2 2.8.3. Hydrobiology investigations No direct hydrobiology investigations have been carried out in this lake. 2.9. LAKE LANGVATN Lake Langvatn (watershed of the River Dammasjoki) is located 34 km to the north of the town of Zapolyarny. The elongated lake is relatively small (area of the lake 0.87 km2), not deep (maximum depth 21 m), and is of glacial origin. The maximum length is 2.23 km and maxi­ mumwidth 0.57 km. The points ofmax­ imum depth are located in the central part of the lake. The lake belongs to a lake-river system. According to the landscape type, the watershed belongs to the tundra zone, with heights of up to 356 m. Boulder beds occur in almost all parts of the littoral zone. The lake shores are high, and covered by grass and shrub vegetation. The southern shore leads abruptly down to the water. The road to Jacobselv passes along the northern shore. The water of the lake is colourless. Physico-geographical characteristics Watershed River Dammasjoki— Jarfjord (The Barents Sea) Latitude 69°43.553' Longitude 30°35.509' Height above sea level, m 87.0 Maximum length, km 2.23 Maximum width, km 0.57 Maximum depth, m 21 Area, km 2 0.87 Watershed area, km 2 7.3 Study period 2003-2005 Table 32. The organic matter contents (LOI, %) and heavy metal concentrations (цд/д, dry weight) in the surface (0-1 cm) and pre-industrial (14-15 cm) sediment layers. Cfand Cbare the contamination factor and degree of contamination values, respectively. Catalogue of Lakes in the Russian, Finnish and Norwegian BorderArea 93