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 Lake sediment composition in Subarctic watercourse 1027 Fig. 4. Vertical distribution of concentrations of heavy metals (^g/g, dry weight) in sediment cores from Lake Kuetsjarvi. input o f heavy metals from the Pechenganickel Company over the latest years. For example, the input o f N i was reduced from 12.9 up to 4.4 to n /y e a r from 1990 to 2007, although emissions o f this heavy metal into the atmosphere remain approxi­ mately identical during this period, ranging from 300-350 to n /y e a r (official data o f the Kola Mining and Metallur­ gical Company - h ttp ://www .ko lagm k .ru /) . For the total period o f activity o f the Pechenganickel Company it has earlier been estimated that 310 tons o f Ni, 120 tons o f Cu, 14 tons o f Co, 19 tons o f Zn, 0.087 tons o f Cd, 0.78 tons o f Pb and 0.053 tons o f Hg have been accumulated in the sediments o f Lake Kuetsjarvi.[11] The vertical distribution o f the concentrations o f Fe and Mn in sediments o f lakes Inari, Bj 0 rnevatn and Kuets- jarvi (station 9 - the deepest water area o f the Lake) is presented in Figure 5. The increase in concentrations o f Fe and Mn in surficial layers o f sediment is similar as