Koroleva I.M. The status of whitefish population from Chuna Lake in the Lapland Biosphere Reserve Russia. International Journal of Environmental Research. 2008, V.2, №2, p. 111-124.

Int. J. Environ. Res., 2(2): 111-124, Spring 2008 Bottom sediments have been sampled by an open-gravitation sampler (Skogheim, 1979). After layer separation (1cm), all the samples were dried out and calcined. After additional preparation, the solutions were analyzed with an atomic-absorption spectrophotometer (AAS-3, Perkin-Elmer 360, 460, 560) in air-propane (Ni, Cu, Co, Zn, Cd, Pb, Mn, Fe, Na, K, Sr, Cr), air-acetylene (Mg, Ca) flame. All the metal concentrations are given in microgram per gram (mkg/g) of dry weight. The freshwater ecosystems pollution level has been assessed by the Hekanson method (Hekanson, 1980) adapted to the European subarctic conditions. The contamination factor (Cf) was calculated as the quotient of the element concentrations in the surface bottom sediments layer (0-1 cm) and the background value in the deepest part of the column (Dauvalter, 1999). The main object under study was Whitefish (Coregonus lavaretus L.). The catches were carried out near the Central manor of the reserve (a feeding area) and in the westernmost part of the lake, in the mouth of the Verkhnyaya Chuna (a spawning area). In total, 777 samples was caught. Catches were carried out by a standard set of gill nets, 25 m long and 1.5 m high, and mash sizes: 16, 20,31,36, 40 mm, made of 0.15 mm-dia nylon monofilament thread for small-cell nets and that of 0.17mm-dia for large-cell nets, which allowed catching fish of 10-46 cm in size. Each net was fixed separately from the other in the littoral zone at right angle to the shore and in the profundal zone, up to 10 nets in one series. Each individual was analyzed for weight, length according to Smith, and for the standard length, fatness, the degree of stomach filling. Maturation of gonads was determined visually in accordance with the standard fieldmethods (Pravdin, 1966). The age was determined by scale. To assess the long-term alternations ofwhitefishpopulation, archivematerials and publications of the Lapland biosphere reserve were used (Vladimirskaya, 1950, 1951, 1956; Reshetnikov, 1962, 1963, 1964a,b, 1966, 1967, 1975). The state of the whitefish organism has been analyzedby patho-morphological studies (Arshanitsa and Lesnikov, 1987; Kashulina, et al., 1999; Reshetnikov, et al., 1999). The indivuduals were dissected after a short period of time after catch. Special attention has been paid to outer change (the cover color, presence ofmucus, bones deformation). In gill analyzing, assessment was made of gill coloration, the presence of mucus and necrotic foci, and the form of rakers. In analyzing the inner organs (liver, kidney, gonads), assessment was made oftheir size, form, consistence, the presence ofhemorrhages and necrotic foci development. To determine the Cu and Ni content in organs and tissues, 10-15 individuals, of the equal size, were selected. Liver, kidney and gills were sampled. The individuals selected were dissected and sampled with knives, scalpels and forceps made of stainless steel. To be further analyzed, the organ samples were frozen. In laboratory, the samples were dried to the constant weight at 90 oC, after that the organic matrix was taken out in the concentrated nitrogen acid solution in a microwave decomposition system (Multivave 3000, Anton Paar, AUSTRIA) with further filtration. The Cu and Ni content in gills, liver and kidney was determined by atomic absorption spectroscopy with atomization in flame or graphite tubes using Perkin- Elmer 5000 with a graphite furnace (HGA-400). All the metal concentrations are given in microgram per gram (mkg/g) of dry weight with detection limit of 0.02 mkg/g for Cu and 0.05 mkg/g for Ni. The sample solutions investigated for heavy metals content have been compared with certified standard sample Fluka Chemie GmbH, Switzerland. The quality control was realized using standard sample DORM-2. Statistical analysis The reliable difference in biological indices and that in the Cu and Ni concentration in organs and tissues ofwhitefishwas statistically interpreted using the t-criterion. RESULTS & DISCUSSION The precipitation analysis has shown that the amount of sulphates, nickel and copper deposited in the lake catchment area annually (on the average over a long-term period) accounts for 1.7, 17.1 and 18.8 tons. The model calculation of long-term load in 1980-2001 has revealed considerable pollutants intake into the Lake Chuna (Table 1). According to the main hydro-chemical indices, the lake is characterized as an oligotrophic ultra-fresh water body. The hydro-chemical composition of water in Lake Chuna is affected by long-term drainage of heavy metals and aluminium from the catchment area, which is due to air-borne industrial emissions from Severonikel copper-nickel smelter. As a result, the hydro-chemical water composition has changed greatly to become typical of air-borne industrial