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 1031 which are emitted into atmosphere by smelters, and tran s­ fer on longer distance (similarly to SO2) in comparison with other heavy metals. Hence, increased concentrations o f chalkophile elements were no t typically observed close to the Petchenganickel smelters. The highest concentrations o f Fe and Mn in surficial sed­ iment layers among the investigated lakes were observed in Lake Inari (Table 2), which likely is connected to the large size (area, depth, and water volume) and its oligotrophic state with high oxygen supply o f water and surficial sedi­ ments, causing the accumulation o f these metals in oxidized and poorly soluble forms in the top sediment layers. Alkaline-earth metals (Ca, Mg and Sr) were found in highest concentrations in the surficial layer o f sediments o f Lake Kuetsjarvi. This is connected with the increased input o f these metals in the sewage from the Pechengan- ickel Company, including suspended particles that cause the accumulation o f these metals in the sediments. Factor and degree of contamination of lake sediments The intensity o f pollution o f water objects can be estimated by means o f concentrations o f heavy metals in the surficial sediment layer. The technique o f definition o f factors and degrees o f contam ination o f water ecosystems by heavy metals in sediments by means o f Cf and Cd is described by Hakanson.[3,25] The technique o f definition o f factor o f anthropogenous enrichment o f sediments has also been de­ scribed by a number o f researchers.[1,9,46] Calculated values o f Cf and Cd are presented in Table 3. Maximal values o f Cf were for almost all investigated heavy metals observed in the sediments o f Lake Kuetsjarvi (Table 3), which is related to a direct input o f wastewaters from the Pechenganickel Company. Lake Kuetsjarvi is ac­ cording to the classification o f Hakanson,[3] characterized by high values o f Cf for all heavy metals except Zn, for which only moderate pollution is revealed. Lake Bjornevatn is characterized by high Cf values for N i and Hg, considerable for Cu, As, Cd and moderate for all other metals. An influence o f sewage input from the Pechenganickel Company was also found downstream in Lake Skrukkebukta with considerable contam ination o f Ni, Cf-values for Cu and Cd on the borderline between moderate and considerable, and only moderate contam i­ nation for all other metals. For the lakes located upstream the Pechenganickel Com­ pany, high and considerable contam ination o f Hg (Heste- foss and Ruskebukta, respectively), and also considerable contam ination o f Cd (Hestefoss) were revealed. Low and moderate Cf-values were recorded for all other heavy met­ als in these lakes. In Lake Vaggatem, moderate Cf-values were observed for all metals (Table 3). Lake Inari was characterized by high Cf-values for As, considerable for Pb and Cd, and moderate for Hg. Other heavy metals in sediments o f Lake Inari had Cf-values on the borderline between low and moderate (Table 3). As a whole for all investigated polluting elements, Lake Kuetsjarvi was by far characterized by the maximum con­ tam inations (i.e., high value o f Cd, Table 3). According to the classification o f H akanson ,[3] a high o f Cd-value was also revealed in Lake Bjornevatn, although it was much lower than in Lake Kuetsjarvi. A considerable value o f Cd was found in Lake Inari owing to serious contam ination o f the sediments by chalcophile elements. Lakes Skrukke- buk ta and Hestefoss had Cd-values on the borderline be­ tween low and moderate. Low Cd-values were recorded in Ruskebukta and Vaggatem. Conclusions The highest background concentrations o f the majority o f heavy metals (Ni, Zn, Co, Cd, Hg, As) in sediments were found in the southern part o f Lake Kuetsjarvi. This is caused by geochemical and morphometric features o f the catchment area as there are large copper-nickel sulphide deposits in the southern and eastern parts o f the lake. The highest background concentrations o f Cu and Pb in sed­ iments were observed in Ruskebukta and Skrukkebukta, Table 3. Values of factor of contamination (Cf) and degree of contamination (Cd) in lake localities in the Inari - Pasvik watercourse. No Lake, station, depth, m Cu Ni Zn Co Cd Pb As Hg Cd 1 Inari-1 0.8 1.0 1.1 1.0 5.8 5.7 4.5 2.8 22.6 2 Inari-2 0.8 0.9 0.9 1.0 2.1 4.3 9.1 2.3 21.4 3 Hestefoss 0.9 0.8 0.8 0.9 3.9 1.3 1.1 6.8 16.5 4 Ruskebukta 1.1 1.1 0.8 0.8 1.7 1.4 2.0 4.2 13.1 5 Vaggatem 1.4 1.5 1.0 1.0 1.5 1.7 1.3 2.9 12.1 6 Kuetsjarvi-6 20.8 52.9 2.3 5.2 15.8 4.1 3.1 0.9 105.3 7 Kuetsjarvi-7 4.0 2.2 2.3 3.0 5.2 10.1 3.5 8.1 38.5 8 Kuetsjarvi-8 20.0 42.8 2.3 4.9 13.2 4.2 7.3 4.7 99.5 9 Kuetsjarvi-9 33.5 125.7 3.0 11.6 32.1 5.5 16.4 8.5 236.2 10 Bjornevatn 5.6 6.9 2.6 2.0 3.1 0.9 5.2 12.2 38.3 11 Skrukkebukta 2.9 4.3 1.0 1.6 3.0 1.9 1.7 0.8 17.4