Ecosystem and human health assessment to define environmental management strategies: the case of long-term human impacts on an Arctic lake / Moiseenko T. I., Gashkina N. A., Voinov A. A. [et al.] // The Science of the Total Environment. - 2006. - Т. 369, № 1-3. - С. 1-20.

T.I. Moiseenko et al. /Science o f the Total Environment 369 (2006) 1-20 9 anthropogenic succession for fish: we do not have good estimates for the volumes of fish withdrawn from the lake and do not know how fishing changed the characteristics and structure of the fish population. As the toxic impact declined, fish diseases became less prominent (Table 4) . Physiological conditions have improved: there were no more fish with nephrocalcitos and scoliosis in the catches. Cases of whitefish diseases were less dramatic than in previous years, but there is evidence of chronic diseases under prolonged influence of small doses of contaminants. 4. Metals in fish as reflection of local pollution and enrichment of Northern Chemosphere It is well known, that fish accumulate metals during their life span. In some works it was shown, that contents ofmetals in fish reflect levels of pollution more accurately than the indices of contaminant content in water (Forstner and Wittman, 1981a,b; Moore and Rammamoorthty, 1983; Spry and Wiener, 1991; Moi­ seenko and Kudryavtseva, 2002) . Nickel and copper released by the “Severonickel” enterprise belong to essential elements. These elements are functionally immanent in certain concentrations for all living organisms. However with higher concentra­ tions in the environment they act as toxic contaminants. Fig. 2 s hows the contents of nickel in water and in organisms of whitefish in Bol’shaya Imandra. Maximal nickel concentrations in whitefish were during 1978-86, when the pollution level was peaking. During this period rate of fish disease, especially nephrocalcitos was very high. Toxicity of technogenic nickel is very high — it has carcinogenic, gonadotoxic, embryotoxic and cumulative properties (Sydorenko and Itskova, 1980; Moore and Rammamoorthty, 1983 ). Most ofNi accumulation occurs in the kidney (Moiseenko and Kudryavtseva, 2002) . There is an exponential dependence between the concentration of nickel in water and its contents in kidneys, while bioaccumulation of Ni in the organism has a linear effect on the disease occurrence (%) (Fig. 3) . Clearly the occurrence of nephrocalcitos is determined by water pollution and nickel accumulation in organ­ isms. We can assume that accumulation of this element in kidneys from 2 up to 7 p.g/g of dry weights causes disease. Currently content of nickel is lower, and cases of nephrocalcitos are not noticed. However other diseases of kidneys, fibroelastosis, are recorded for whitefish. Moiseenko and Kudryavtseva (2002) d ocu­ ment characteristics of these diseases in detail. Copper accumulates mainly in the liver of fish, where active biochemical processes take place (Bradley and Morris, 1986) (Fig. 2) . However, no direct links with contents in water detected. Moiseenko and Kudryavt­ seva (2002) show that accumulation of this element is high with concentrations of the element of up to 5 mkg/l, however in conditions of high toxicity of water there is a decrease of Cu accumulation in liver due to pathological degeneration ofthis organ and destruction of the ferment systems. It should be noted that nickel and copper are added to water together with other trace metals. It is possible that they have a synergetic effect causing even higher occurrence of disease in fish. Strontium pollution comes from the apatite-nephe- line industry. Ions of Sr are involved in the exchange with Ca. They have a faster rate of exchange, and gradually impede normal skeleton calcification (Kovalsky, 1974, Chowdhuury et al., 2000) . Absolute concentrations of Sr in water are not dangerous, however it is the interaction with calcium that causes problems. Dangerous Ratios of Sr/Ca in water that are less than 1/60 are considered hazardous. In Lake Imandra this interrelation is about 1/57. The connection a) 40 2 5 - *7?----- 0-1----------------------1----------------------1----------------------1----------------------1----------------------i----------------------1 0 5 10 15 20 25 30 Ni in water, (ig/I Ni in kidney, (i.g/gdry w. Fig. 3. Relationships between Ni accumulation in whitefish kidneys (Coregonus lavaretus ) and (a) occurrence of nephrocalcitosis; (b) Ni concentration in water.