Chemical composition of lake sediments along a pollution gradient in a Subarctic watercourse / Dauvalter V., Kashulin N., Sandimiriv S. [et al.] // Journal of Environmental Science and Health. Part A. - 2011. - Vol. 46. - P. 1020-1033.

Downloaded by [Vladimir Dauvalter] at 21:54 24 November 2013 1026 Dauvalter et al. 0 100 200 Cu, ng/g 0 100 200 Zn, ng/g 0 0.1 0.2 0.3 Cd, ng/g 0 5 10 15 As, jig/g Fig. 3. Vertical distribution of concentrations of heavy metals watercourse. the Pechenganickel Company it is possible to calcu­ late the approximate sedimentation rate as 1.7 and 1.1 mm /years for the above-named stations, respec­ tively. Sedimentation rates in Lake Kuetsjarvi were ear­ lier by indirect determinations estimated equal to 1.5­ 3 mm /years.[8,11,12,33] Elements such as Cu, Cd and Pb had surficial maxima in sediments at all stations in Lake Kuetsjarvi (Fig. 4). Other investigated heavy metals (Ni, Co, Zn, Hg and As) 0 20 40 Co, (ig/g (Mg/g, dry weight) in sediment cores from lakes in the Pasvik were characterized by maximal concentrations at sediment depths o f 2-6 cm in practically all sampling stations o f the lake except station 7 (Fig. 4). Similar vertical distributions have been noticed in sediments o f Lake Rjussjanjarvi lo­ cated 17 km north-east o f the Pechenganickel smelters.[8,20] Reductions in the concentrations o f these elements in the top 1-2 cm o f sediments in Lake Kuetsjarvi can be ex­ plained by changes o f physical and chemical conditions in the lake and its catchment basin, and also a decreasing