Zonal factors of fresh water ecosystems’ resistance to anthropogenic pollution

Unreasonable application of unified federal maximum allowable concentration values for fisheries in five different natural-climatic zones of Russia is known to entail unpredictable ecological failure, especially in northern water basins characterized by low biological and hydro chemical buffering capacity. The purpose of the study was to identify zonal regularities and specific features of the freshwater ecosystems’ resistance to anthropogenic pollution. The study of the aquatic habitat factors’ effect on the toxicity of metal salts, oil products, and pesticides was conducted in three regions (Southern Urals, East-Kazakhstan Province, and Karelia). It helped to establish an existing connection of toxic resistance of representative hydrobionts and toxicity of pollutants of different chemical nature with hydrochemical regime and trophic status of the water bodies. Particularly, regression analysis of experimental data demonstrated that with the increase of the values of aquatic habitat background features from north to south etc. the toxicity of copper, nickel, zinc, lead, and potassium in acute and chronic lethal concentrations consistently diminishes. The detected qualitative and quantitative differences in resistance of aquatic ecosystems, belonging to different natural-climatic zones, to anthropogenic pollution strongly indicate biological inexpediency and ecological danger of the applied system. Unified toxicological regulations inherent to the system are harmful when used without necessary consideration of biotic and abiotic buffering of freshwater bodies.