Sandimirov S. Pollution of the Sediments of the Paz River basin / In State of the environment in the Norwegian, Finnish and Russian border area. The Finnish Environment. Finland, Jyvaskyla: Kopijyva Oy. 2007, №6, 98p.

1000 100 10 tl 0.1 0.01 I п □ Hestefoss □ Ruskebukta H Vaggatem ■ Bjornevatn □ Skrukkebukta И Cu Ni Zn Co Cd Pb As Hg 1 Fig 3. Distribution o f the element concentrations in the upper layer (0 - 1 cm) o f the sediment cores downstream the investigated Paz River parts. the capture and accumulation o f mobile heavy metals (e.g., Ni, Cu, and Cd) in lake sediments. The prevailing south-western winds mainly spread the emission plume in the north-eastern and southern direction (bottom sediments in lakes located 40 km and farther south o f Nikel’ are con­ taminated only slightly). In northern areas o f Norway and Finland, deposition o f these elements with precipitation is low. In these places, emissions o f the plant only slightly affect the heavy metal content o f top layers o f lake sediments. The Lake Bjornevatn received the contaminated water from Lake Kuetsjarvi accumulates the maximum concentrations in the surface sediment layer o f the almost all contaminated elements (Table 2, Fig. 3). The exception are Pb and Hg, which have the highest concentrations in the top sediment layer in Skrukkebukta and Ruskebukta respectively. Concentrations o f the Ni, Cu, Zn and Co in the top sediment layers o f the Lake Bjornevatn increased during the last ten years in 1.1 - 2.1 times, Cd decreased, and Pb is the same (Dauvalter, 1998). In distribution o f concentration Hg in the top layers o f sediment cores decreasing contents downstream o f the Paz River has been marked (Fig. 3). In top layers o f the sediments in the upper reaches, the concentrations o f Ni, Cu, Co, and Zn do not much exceed their background values. 2.4. The Factor and Degree of Contamination of Lake Sediments Maximum values o f contamination factor (Cf) for the investigated elements were noticed for sediments o f Bjornevatn, polluted by sewage waters o f the Pechenganickel smelters (Table 3). This lake has very high Cf values for Ni and Hg, considerable Cf values o f Cu, Cd and As, and moderate values o f Zn and Co o f according to the Hakanson (1980) classification. In the lakes, 13