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.

302 Environ Monit Assess (2011) 182:301-316 end up in fish and even in humans that consume the fish. Metallurgic industry is a source of serious environmental pollution related to the emission of heavy metals (Kelly 1988;Gunn et al. 1995;Nriagu et al. 1998; Blais et al. 1999; Allen-Gil et al. 2003; Pyle et al. 2005). Heavy metals may enter fish through the body surface, the gills or the diges­ tive tract. The gills are regarded as an important site for direct uptake from the water (Thomas et al. 1983; Dallinger et al. 1987), whereas uptake through the body surface is assumed to play a minor role (Dallinger et al. 1987; Pourang 1995). Food may also be an important source for heavy metal accumulation (e.g. Dallinger et al. 1987; Ptashynski and Klaverkamp 2002), potentially leading to biomagnification and elevated levels in fish. Some of these elements are toxic to fish and other living organisms even at low concen­ trations, whereas others are biologically essential constituents of the aquatic ecosystems, and only become toxic at very high concentrations. In fish, the toxic effects of heavy metals may influence physiological functions, individual growth rates, condition, reproduction and mortality (Rajotte and Couture 2002; Pyle et al. 2008; Rasmussen et al. 2008). Fish are therefore regarded as good indicators of heavy metal pollution in freshwater systems (Rashed 2001; Bervoets et al. 2005), and heavy metal contaminants in fish have been a major environmental focus over the last decades (e.g. McFarlane and Franzin 1980; Kashulin and Reshetnikov 1995; Kashulin et al. 2001; Klavins et al. 1998, 2009; Papagiannis et al. 2004). The heavy metal pollutants may enter the water sys­ tems both via deposition of atmospheric emissions and direct runoff from e.g. slag piles, but the relative roles of these contamination pathways are poorly known. The major metallurgic smelters of the Pechenganickel Company located in Nikel and Zapolyarny in the Kola Peninsula Region in northwest Russia have large emissions of dust, heavy metals and sulphur dioxide (Kashulin and Reshetnikov 1995; Moiseenko et al. 1995; Reimann et al. 2000). The central freshwater system in this region is the Inari-Pasvik watershed in the border area between Finland, Russia and Norway. The lower part of the watercourse drains the Nikel smelters directly through the lake Kuetsjarvi. Whitefish (Coregonus lavaretus) is the dominant fish species in the watercourse (Amundsen et al. 1999). High levels of heavy metal contamination have been recorded in water and sediments in the vicinity of the Nikel smelters (Dauvalter 1994, 1998; Moiseenko et al. 1995; Dauvalter and Rognerud 2001; Lukin et al. 2003), possessing a threat to fish and other biota (e.g. Kashulin and Reshetnikov 1995; Amundsen et al. 1997; Mousavi et al. 2003), and potentially also a health problem for humans consuming fish from the watercourse. Increased levels of heavy metals have also been observed in terrestrial plants, birds and mammals in these areas (Kalas et al. 1995; Odasz-Albrigtsen et al. 2000; Steinnes et al. 2000; Myking et al. 2009). The Nikel smelters constitute a point source of industrial pollution for the border region and the Inari-Pasvik watercourse. Lake localities sit­ uated at variable distances from the pollution source should expectedly experience different heavy metal exposures. In the present study, we contrasted the contents of Ni, Cu, Cd, Zn, Pb and Hg in water and sediments and in gills, liver, kidney and muscle tissue of two ecologically different whitefish morphs (zooplanktivorus and benthivorous; Amundsen et al. 2004a; 0stbye et al. 2006) from five lake localities situated along a spatial gradient of increasing distance (5-100 km) to the Nikel smelters. We also ex­ plored potential impacts of heavy metal contam­ inations on somatic growth, condition and repro­ duction of the whitefish morphs. We hypothesised that the heavy metal contaminations in environ­ ment and fish would decrease with increasing dis­ tance to the pollution source, and that impacts of the contaminations would be most severe in the vicinity of the smelters. Materials and methods Study area and fish communities The Inari-Pasvik watercourse covers an area of approximately 1,250 km2, with a catchment area of nearly 21,000 km2. It originates in Finland, runs north into Russia and then forms the border be­ tween Norway and Russia over a distance of about Springer