THE ENVIRONMENTAL CONDITION OF LAKE BILIKOL AFTER ANTHROPOGENIC POLLUTION FROM THE ASA RIVER, KAZAKHSTAN

The ecological condition of Lake Bilikol under conditions of anthropogenic pollution from the Asa River has been recently documented. Major pollution events occurred in 1983-1984 and 1988 after the accidental release of industrial effluents from the Zhambyl Phosphorus Factory into the Asa River. This also became the starting point of environmental deterioration. In subsequent years, the flora and fauna of the lake were partially self-restored, but because of the impact of pollutants, the lake is still in the stage of severe degradation. This article examines changes in the ecological condition of Lake Bilikol under anthropogenic pollution inputs from the Asa River, which is the main source to the lake. This article also includes a description of the geographical location, information on lake fauna (fish stocks, water, and water birds), and hydrography and anthropogenic impacts. The level of anthropogenic impact and its duration over time, which multiplied after the accidental release of industrial wastewater from the Zhambyl phosphorus plant into the Asa riverbed in 1983-84 and 1988, is the starting point of ecological degradation of the lake and is reviewed in more detail. Chemical analysis results of water and soils of the lakebed, which are mainly polluted by phosphates and fluorides, and their transformation during the last 30 years are presented in methodical terms. In certain years, there was a partial self-restoration of the lake ecosystem (water quality, fauna, and flora). Nevertheless, the lake is currently experiencing severe ecological degradation because of the long-term influence of chemical pollutants. In the future, environmental protection measures are needed to plan practical measures for the rehabilitation of the lake using methods both for the acceleration of biological self-remediation and for hydro-mechanical cleaning of the lakebed and lake water.