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 1032 Dauvalter et al. respectively. The background concentrations o f heavy m et­ als in sediment o f Lake Inari and Kuetsjarvi are approx­ imately equal, and similar to the levels observed in Lake Im andra in the central Kola region.[8,11] Atmospheric emissions o f smelters and sewage from slag piles, tailing dams and mines o f the Pechenganickel Com­ pany have caused the maximal concentrations o f all inves­ tigated heavy metals in surficial sediment layers o f Lake Kuetsjarvi. Kuetsjarvi is the most polluted lake o f all in­ vestigated lakes, in particular owing to the input o f sewage from industrial area through River Kolosjoki. Values o f factor o f contam ination (Cf) also reached the maximal amounts in Lake Kuetsjarvi (126 for Ni, 34 for Cu, 12 for Co, 32 for Cd, 10 for Pb, 16 for As). The basic p a rt o f the studied heavy metals (Ni, Co, Zn, Hg and As) is charac­ terized by maximum concentrations at sediment depths o f 2 -6 cm at practically all stations in the lake. The reduction in the concentrations o f these elements in the top 1-2 cm o f the sediments in Lake Kuetsjarvi are likely explained by decreasing inputs o f heavy metals from the Pechenganickel Company over the last decades. Other elements (Cu, Cd, Pb) have surficial maxima in the sediments at all stations o f the lake which can be connected to a constant input o f these elements (for Cu - 0.1-0.2 ton s/y ea r for the last decade). Downstream in the Pasvik watercourse in the lakes Bjornevatn and Skrukkebukta, a reduction in the heavy metals contents in surficial sediment layers was observed, even though pollution remains relatively high for Lake Bjornevatn and considerable for Lake Skrukkebukta. The main polluting elements in these lakes are the heavy m et­ als entering in the sewage runo ff from the Pechanganickel Company including Ni, Cu, Co and Zn, but also the chal- cophile elements (Hg, As, Cd) are found in high concentra­ tions in surficial sediments o f Lake Bjornevatn. In investigated lakes subjected to air pollution and input o f household sewage o f settlements located in the catch­ ment area, no essential increase was found in the surfi- cial sediment contents o f heavy metals emitted into the atmosphere in significant amounts by the Pechenganickel Company (i.e., Ni, Cu, Co, Zn). However, in these lakes and especially in Lake Inari, the largest and most remote site from the Pechenganickel Company, substantial increase (until 5-10 times) in the concentrations o f chalcophile ele­ ments (Pb, Cd, Hg and As) was revealed in the surficial sedi­ ment layers in comparison with background contents. This confirms the conclusion o f many ecologists about global environmental contam ination with chalcophile elements of the Arctic and Subarctic zones o f No rthern hemisphere. Average sedimentation rate was estimated to be higher in all investigated lakes (1-3 mm /years) than the average for lakes o f No rthern Fennoscandia (less than 1mm /years, according to calculations by N o rton et al.[26]). This is likely connected to the input o f sewage with high contents o f the suspended particles (Kuetsjarvi) and to the flow regulations which have transferred the lakes into a status o f water stor­ age ponds with decelerating current speeds that promote sedimentation o f suspended particles containing polluting substances, and hence an increase in sedimentation rate. In conclusion, our studies demonstrate that the met- allurgic processing o f the Petchenganickel Company has resulted in comprehensive heavy metal pollution and con ­ tam inations o f lakes sediments in the Inari-Pasvik water­ course over the approximately 70 years o f activity. The pollution impact on the sediments is most severe in Lake Kuetsjarvi in the vicinity o f the smelters, intermediate in lake localities in the main watercourse downstream the metallurgic enterprises and least in lake localities in the upstream part o f the watercourse. Elimination o f the heavy metal problems and the negative consequences connected with them (e.g., disappearance o f hydrobiont species sensi­ tive to pollution and eutrophication, reduction o f produc­ tivity o f reservoirs including productivity o f fish, unfitness o f water and fish for consumption and others) is impossi­ ble without close cooperation and jo int efforts o f the local communities, politicians, scientists and business organisa­ tions o f three neighbouring countries. Acknowledgments This research was supported by the Interreg IIIA Kolarctic project “Development and implementation o f an environ­ ment monitoring o f assessment programme in the jo in t Finnish, Norwegian and Russian area” .The authors thank staff o f the laboratory o f water ecosystems o f INEP, partic­ ularly Sergey Makoganuk, Dr. Lubov Kudryavtseva, and N ina Voevodina, for their substantial support during the course o f this research. We would like to thank anonymous reviewers for constructive comments to the earlier version. References [1] Alhonen, P. Heavy metal load of Lake Iidesjarvi as reflected in its sediments. Aqua Fennica 1986, 16, 11-16. [2] Forstner, U. Lake sediments as indicator of heavy-metal pollution. Naturwissenschaften 1976, 63, 465-470. [3] Hakanson, L. An ecological risk index for aquatic pollution control - a sedimentological approach. Water Res. 1980, 14, 975-1001. [4] Dauvalter, V.A. Heavy metal concentrations in lake sediments as an index offreshwater ecosystem pollution. In Disturbance and recovery in Arctic lands; an ecological perspective ; Crawford, R.M.M., Ed.; Kluwer Academic Publishers: Dordrecht, The Netherlands, 1997; 333-351. [5] Rognerud, S.; Fjeld, E. Regional survey of heavy metals in lake sediments in Norway. AMBIO 1993, 22, 206-212. [6] Rognerud, S.; Skotvold, T.; Fjeld, E.; Norton, S.A.; Hobak, A. Con­ centrations of trace elements in recent and preindustrial sediments from Norwegian and Russian Arctic lakes. Can. J. Fish. Aquat. Sci. 1998, 55, 1512-1523. [7] Dauvalter, V.A. Concentrations of heavy metals in superficial lake sediments of Pechenga district, Murmansk region, Russia. Vatten 1992, 48, 141-145. [8] Dauvalter, V.A. Heavy metals in lake sediments of the Kola penin­ sula, Russia. Sci. Tot. Environ. 1994, 158, 51-61.