Assessment of watercourses of Astrakhan by hydrobiological and microbiological indicators

Abstract

The paper focuses upon the control over environmental pollution of water bodies by human waste products in urban areas, which can be carried out by monitoring hydrobiological indi-cators. In the course of study undertaken in May 2017 and 2018 there was assessed the ecological and sanitary status of the Volga and Kutum rivers that flow on the territory of Astrakhan. Samples were taken at four stations; the choice of station location was determined by the presence of pollutant sources: proximity of the city market or the power plant. Quantitative and qualitative indicators of the state of phytoplankton were used as hydrobiological indicators; the total number of bacteria and the total content of coliform bacteria were evaluated as microbiological indicators. During the study period the ecological and sanitary state of water was rated as satisfactory. The number of algae taxa increased insignificantly (by 3 units), diatoms predominated in the number of genera and number. Despite the presence of 4-5 species of pure water representatives in the investigated waters, the sanitary and bacteriological situation at all the studied stations was found unfavorable; the water was characterized as polluted and dirty. In 2018, there was registered deterioration of water quality compared to 2017, while the calculated saprobity index in the Kutum river indicates the water quality improvement downstream. The increasing value of the water saprobity index in the Kutum river indicates a tendency toward the growing level of organic pollution and necessitates a comprehensive analysis of hydrobiological indicators for systematic monitoring the aquatic environment.