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.

310 Environ Monit Assess (2011) 182:301-316 Lake locality Fig. 7 Size (a) and age (b) at first reproduction es­ timated by logistic regression for SR (filled squares ) and DR whitefish ( circles ) in the studied lake localities (1 Kuetsjarvi, 2 Skrukkebukta, 3 Vaggatem, 4 Rajakoski, 5 Lake Inari). Vertical bars indicate 95% confidence limits Discussion For most of the examined metals there was a pro­ nounced and significantly decreasing trend in their concentrations in water, sediments and fish tissues with increasing distance to the smelters. In gen­ eral, there were very high levels of heavy metals in Kuetsjarvi, a steep decline to moderate levels in Skrukkebukta ca. 16 km downstream, and a further reduction towards low levels in the other three localities situated upstream at more remote distances (40-100 km). In particular, the Ni con­ centrations were very high in Kuetsjarvi compared to the other lake localities, but also Cu and Cd and to a less extent Pb exhibited elevated concen­ trations. These elevated concentrations were also reflected in strong correlations between element levels in the environment and in fish tissues, in particular in gills, liver and kidney, but for Ni also in muscle. Hence, our study clearly demonstrates that the Nikel smelters constitute a point source of severe heavy metal pollution with highly elevated concentrations observed both in the environment and in whitefish. The main bulk of heavy metals being discharged through the smokestacks appar­ ently experiences rapid fallout and precipitation, and the pollutants are thus mainly deposited in the vicinity of the smelters. Only moderate amounts of the heavy metal contaminants seem to be trans­ ported at further distances through wind disper­ sal of atmospheric emissions. Similar conclusions have also been reached in other studies related to the spatial distribution of heavy metals in the regions around metallurgic smelters. Large-scale regional analyses of ecosystems from the Kola Peninsula and from the Taimyr Peninsula have for instance revealed that the majority of heavy metal emissions were deposited as particulates near the sources (Rognerud et al. 1998; Blais et al. 1999; Reimann et al. 2000; Allen-Gil et al. 2003). In addition to atmospheric emissions, the sewage runoff from slag piles and other smelter facilities is another highly important source for the observed heavy metal contamination in Kuetsjarvi. The metal effluents and emissions entering the lake may also be transported fur­ ther downstream by the water flow, but a rather abrupt decline in heavy metal concentrations both in sediments and water from Kuetsjarvi to the downstream Skrukkebukta was evident. Appar­ ently, the deeper parts of Kuetsjarvi function as a sedimentation trap for heavy metals, and very high contamination levels were observed in the deep sediments of the lake. The downstream water transportation of heavy metals is likely also restrained by the narrow and shallow strait that connects Kuetsjarvi to the main stem of the watercourse. In the two whitefish morphs, the spatial declines in metal concentrations in fish tis­ sues were generally smaller than the respective declines observed for water and sediments. The mean Ni concentration showed a twofold decrease in muscle tissue and a tenfold decrease in liver, gills and kidney tissue. In the environment in Springer