Ecological assessment of lake Akbas by hydrophysical, hydrochemical and algological indicators

Abstract

This paper evaluates the results of hydrophysical and hydrochemical indicators of Lake Akbas of
the Kokshetau State National Natural Park, which belongs to the category of specially protected natural
areas. Changes in the lake area over a period of about 50 years are shown. In terms of water color and
turbidity, there has been a decrease over the past 3 years. The area of the Akbas lake basin has decreased
by 15.3% over the past 50 years. During the study period, the content of dry waste in the lake water
exceeded the MAC by 1.1–1.5 times annually. Lake Akbas is moderately polluted in 2018-2019 in terms
of the level and quality of class III pollution. However, it was found that some hydrochemical parameters
exceed the MAC. Along with the hydrophysical and hydrochemical indicators of Lake Akbas, we identified the species composition of microalgae in the lake, seasonal changes and conducted a systematic
analysis. As a result of the study, the algae flora of Lake Akbas consisted of 61 species, 20 of which are
indicator-saprobic microalgae. To study the sensitivity of algae to environmental factors and various
chemical reactions, we carried out biotesting of water samples from Lake Akbas. Biotesting showed
that the Chlorella sp-3K strain is moderately sensitive to toxic concentrations in Lake Akbas. Researches
have shown that bioassays for microalgae in lake water are quick and easy and complement the results
of chemical studies. According to the results of hydrophysical, hydrochemical studies and biotesting of
algocenoses, it was determined that the water of Lake Akbas belongs to 3 classes of pollution.
Key words: Нydrophysical and hydrochemical indicators, algoflora, biotesting.