ОЦЕНКА СТЕПЕНИ ЗАГРЯЗНЕНИЯ ДОННЫХ ОТЛОЖЕНИЙ МАЛЫХ РЕК РОСТОВСКОЙ ОБЛАСТИ

Abstract

Purpose: to study the degree of pollution of bottom sediments of small rivers of the Rostov region. Materials and Methods: the research was carried out in 2019–2020 according to the decree of the Government of Rostov region of 25.09.2013 no. 595 and in accordance with the orders of the Ministry of Natural Resources and Environment no. 432 of 08.10.2014 and no. 112 of 24.02.2014. The work on monitoring the pollution of bottom sediments carried out by the authors included: samples selection, description, conservation, delivery and preparation; conducting an integral assessment of toxicity. The studies were carried out on microalgae according to the biotesting method for inhibiting the growth of unicellular algae Chlorella vulgaris Beijer and ciliates Paramecium caudatum. A sample was considered toxic if the value of the toxic effect was 50 % or more. In case of detecting high toxicity, the repeated sampling to determine the prevailing priority and specific pollutants was carried out. Results: according to the approved research program, 70 samples (33 in 2019, 37 in 2020) at 21 water bodies were selected. As a result of an integrated assessment of the toxicity of bottom sediments of water bodies, an excess was revealed only in two samples taken in 2019 at the site of the river Temernik. Conclusions: the results of biotesting did not reveal an excess of the permissible toxicity values in all areas of water bodies, except for the river Temernik, where a slight excess was revealed (55 %). In this case, when forming a program for the environmental protection measures implementation, more attention should be paid to a number of other environmental problems of water bodies in the region, among which a special place is taken by low water associated with both climate change and excessive water consumption for the needs of economic activities, land plowing to the water's edge, washing out dams and other blocking structures, including due to improper functioning of culverts.