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

Table 26. The organic matter contents (LOI, % ) and heavy metal concentra­ tions (цд/д, dry weight) in the surface (0-1 cm) and pre-industrial (16-17 cm) sediment layers. Cfand Cd are con­ tamination factor and degree ofcontamination values, respectively. Fig. 41. Vertical distribution of the concentrations of Cu, Ni and Pb (pg/g, dry weight) in the sediment core of Lake Gardsjoen. metals range from 1.5 up to 5.7 (Table 26), i.e. the values correspond to moderate and considerable (Pb) contamination. Lead has the highest Cf value. The contamination factor values of the other heavy metals are low. The degree of contamination value (15.0) for this lake corresponds to moderate contamination. Lake Layer, cm LOI Cu Ni Zn Co Cd Pb As Hg C , . Gardsjoen 0-1 21.89 66 72 58 12 0.18 17.7 1.52 0.082 16-17 18.91 41 28 81 25 0.23 3.1 0.94 0.056 c, 1.6 2.6 0.7 0.5 0.8 5.7 1.6 1.5 15.0 2.3.3. Hydrobiology investigations No direct hydrobiological investigations have been carried out in this lake. 2.4. LAKE GJOKVATN Lake Gjokvatn (watershed of the River Paz) is located 58 km to the south-west of the town of Nickel. The elongated, oval-shaped lake is relatively small (area of the lake 0.62 km2), not deep (maxi­ mum depth 12 m), and is of glacial ori­ gin. The maximum length is 1.22 km and maximum width 0.60 km. The points of maximum depth are located in the cen­ tral part of the lake. The lake originates from the River Gjekbekken. According to the landscape type, the watershed belongs to the forest zone, with heights of up to 180 m.The lake shores are high and covered by pine forests and shrub vegetation. Boulder beds occur throughout almost the whole littoral zone. Physico-geographical characteristics Watershed River Gjokbekken— River Paz CGjnkhnktal Latitude 69°09.181' Lonqitude 29°05.910' Height above sea level, m 96.0 Maximum lenqth, km 1.22 Maximum width, km 0.60 Maximum depth, m 12 Area, km 2 0.62 Watershed area, km 2 6.37 Study period 2004-2005 80 Catalogue o f Lakes in the Russian, Finnish and Norwegian Border Area