Sandimirov S. Heavy metal contents in whitefish (Coregonus lavaretus) along a pollution gradient in a subarctic watercourse. Environ. Monit. Assess. 2011, V. 182, №1-4, p. 301-316.

Environ Monit Assess (2011) 182:301-316 303 120 km, draining into the Arctic Ocean (Fig. 1). It is one of the larger watersheds in Fennoscandia with its 380 km maximum river length and mean flow of 175 m3 s-1 at the outlet. Lake Inari is the central lake locality in the watercourse, covering a total area of 1,102 km2. There are altogether seven water impoundments (hydropower reser­ voirs) between Lake Inari and the sea. Previous rapids and waterfalls have disappeared, and the former river system is now dominated by a num­ ber of consecutive lakes and reservoirs. The water level fluctuations are small and usually less than 80 cm. The watercourse has rich natural resources, constituting a subarctic system with high biodi­ versity and production of fish and other aquatic organisms (Salonen 1998; Amundsen et al. 1999). Fish resource utilisation includes commercial, sub­ sistence and recreational fishery, with an annual harvest ranging from 200 to 600 tons of fish over the last decades (Salonen 1998; Amundsen et al. 1999). The present study included five lake localities situated along the Inari-Pasvik watercourse with an increasing distance from the Nikel smelters (Fig. 1; Table 1) . The uppermost sampling site is located in the southeastern part of Lake Inari (locality 5; 118 m above seal level), approximately 100 km upstream from the smelters. The lake localities Rajakoski (locality 4; 90 m above sea level) and Vaggatem (locality 3; 52 m a.s.l.) are also located upstream from the pollution source, being situated respectively 65 and 40 km from the Nikel smelters in the main stem of the Pasvik wa­ tercourse. Skrukkebukta (locality 2; 21 m a.s.l.) is located downstream the main stem of the Pasvik watercourse, 16 km away from the smelters, whereas Kuetsjarvi (locality 1; 22 m a.s.l.) is lo­ cated in the near vicinity of the smelters in a side-branch connected to the main watercourse through a narrow channel (Fig. 1; Table 1) . All lakes are oligotrophic with some humic impacts and a pH close to neutral (range 6.82-7.11). The geology in the region is dominated by bedrock, mainly containing gneiss, and the watercourse is surrounded by a birch- and pinewood landscape with stretches of boggy land. The ice-free sea­ son of the lakes lasts from May/June to October/ November. The Nikel smelters were constructed for the processing of local ores and have been in oper­ ation since 1932. Since 1971, the smelters have processed copper and nickel ores from Norilsk, Central Siberia, which have particularly high sul­ phur contents (Dauvalter 1994; Kashulin et al. 2001). Out-of-date equipment and technology for metal smelting make this enterprise a serious pol­ lution source in the region (Lukin et al. 2003). At the beginning of the 2000s, the annual emissions of Ni and Cu from the Pechenganickel smelters were around 350 and 180 tonnes, respectively. Sixteen different fish species have been re­ corded in the Inari-Pasvik watercourse, but whitefish is the dominant fish species in all the studied lake localities. The whitefish consists of Fig. 1 Map of the study area with the studied lake localities indicated by numbers (1 Kuetsjarvi, 2 Skrukkebukta, 3 Vaggatem, 4 Rajakoski, 5 Lake Inari) Russia -------- 1 50 km Springer