Vandysh O. Assessment of copper-nickel industry impact on a subarctic lake ecosystem. The Science of the Total Environment. 2003, T. 306, № 1-3, c. 78-83

A. Lukin et al. / The Science o f the Total Environment 306 (2003) 73-83 79 3.5. Fish The Pasvik river system is inhabited by 15 fish species (Amundsen et al., 1993). Our catches from Lake Kuetsjarvi comprised 9 fish species belong­ ing to 8 families: brown trou t- Salmo trutta L., vendace- Coregonus albula L., whitefish- Core- gonus lavaretus L., grayling- Thymalus thymalus (L), pike-Esox lucius L., minnow- Phoxinus phox- inus (L), perch-Perca fluviatilis L., burbot-Lota lota (L) and nine-spined stickleback-Pungitius pungitius (L). Coregonids dominated the fish community in the lake. Brown trout, grayling, burbot showed singular occurrences in our catches. Pike and perch were quite numerous in the littoral zone in the southwestern, western and northwestern parts of lake, in the areas where macrophytes prevailed. Investigations demonstrated that there were practically no fish without visible pathologies in Lake Kuetsjarvi (Table 2 ). Typical pathologies diagnosed in fish were skin depigmentation, defor­ mation of the skull bones, scoliosis, ‘anemic’ ring (whitish rim) on gills, change of the muscle tissue color, change of coloring and consistence of a liver connected with its fatty degeneration, con­ nective tissue growth and nephrocalcitosis in kid­ neys, asymmetric and twisted gonads, etc. High percentage of fish with pathologies prompted us to investigate the accumulation of the priority-pollutant heavy metals (Ni, Cu, Zn) in fish organs and tissues. 3.6. Heavy metal concentrations The concentration of nickel in the tissues of all fish species caught in the impact zone was signif- Table 2 Relative occurrences (%) of whitefish pathology in lake Kuetsjarvi Year Gills Liver Kidney Degree of Degree of Degree of pathology pathology pathology Ni in kidneys 0 0.5 1 1.5 2 2,5 3 3,5 In C f Fig. 6. Dependence of Ni concentrations in fish kidneys (mg g _1 dry wt) on the natural log of contamination factor for Ni in sediments (Cf). Values of Cf increased with proximity to the smelter effluent. icantly higher than in fish from the control waters. The highest Ni concentration was found in the kidneys and gills of fish from Lake Kuetsjarvi, and declined as the distance from the source of pollution increased. There is a strong positive correlation (r2= 0.92) between the Cf of Ni in sediments and Ni concentrations in the kidneys of fish (Fig. 6). For muscles and liver this relation­ ship was not significant. For all species, Ni concentrations were high in the kidneys and gills and low in the muscle, where they were virtually identical in all species and did not change in different water bodies. The greatest relative Ni concentrations in fish from the control waters, both in whitefish and pike, were observed in the gills. The highest Cu concentrations among the inves­ tigated species of fish were recorded in whitefish. The greatest concentrations of copper were found Gonads Change of color Nephrocalcitosis Degree of Degree of Degree of pathology pathology pathology 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1991 8.5 2.8 1.2 32.8 23.2 25.9 12.9 10.2 2.8 6.7 5.6 0.6 2.8 0.6 0 2.3 1.1 0.6 1992 5.7 0.8 13 11.5 23.8 34.4 18.1 10.7 15.6 16.4 4.1 12.3 23 36.9 59 0 04.1 6.6 1995 5.0 4.0 2.0 36.0 29.0 19.0 12.0 16.0 4.0 8.0 3.0 2.0 19.0 28. 7.0 26.0 3.0 1.0 (0) absence of visible deviation from normal, (1) initial stage of disease, (2) medium disorder, (3) irreversibility of disease.