State assessment of ecosystems within the influence zone of the Sayanogorsky industrial complex

Technogenic pollution of naturalcomplexes is quite a new factor for the fauna of the depression, nevertheless, the mechanisms of homeostasis maintenance elaborated inthe course of evolution enable an organism as a complex self-regulating and stable biosystem to level stresses from the disturbing factorsunder the sub-toxic environmental conditions. An advantage of animals-bioindicators is their ability to reflect adequately the state ofa biogeocenosis, the chemical pollution dynamics, and the fermentation mechanism of vital processes functioning, akin to those of ahuman. The Sayanogorsky industrial complex (SIC) consists of the Sayanogorsky and Khakassky aluminum smelters, which are themain contributors to emissions of harmful substances on the territory of the Yuzhno-Minusinskaya depression. The harmful substancesentry into the environment is associated with gas-and-dust emissions of the aluminum smelters. Currently, the most unfavorable situationdevelops at a distance of 0.5-1.5 km from the smelters, solids with F content settle down at a distance of 5 km, while gaseous compoundsare found 30 km away from the source. Fluorine accumulation results in a sharp fall of indices of biological activity of soils andsoil fertility. Investigations showed that intense fluorine accumulation takes place in dominant plant species (Stipa krylovii, Helictotrichondesertorum, Caragana pygmaea), bedding and living roots to a depth of 30 cm. From 1987 till 1991 within the zone of 4 km anincrease of accumulation in bone tissue of small mammals was recorded. It was also found that with the approach to the source of emissionsa decrease in population and simplification of the structure of the herpetobiont complex take place. Research conducted in 2006-2009 showed that in the influence zone of the SIC restructuring of plant and animal communities towards their simplification and decreasein total biomass is in progress. As compared with the data obtained in the 1990s, the pollution bubble has increased notably, andwithin a radius of 15-18 km from the SIC an excess of fluorine is registered in organisms of small mammals. For the first time analysesfor fluorine were made for amphibias, reptiles and birds, which also showed its quite high content. For the herpetobiont population,major reconstruction of the population structure in close vicinity to the sources of emissions (1-3 km) was observed. At present in theinfluence zone of the SIC there occurs a substantial increase in the content of mobile fluorine in soils and its gross form in plants, whichapproaches 4 TLV (threshold limit values), and in bone tissue of animals from 2 to 5.5 TLV, which, undoubtedly, can affect humanhealth and cause initial physiological disorders.

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