Aquatic Bioresources & Environment, Vol. 4, No 1, 2021
Assessment of water quality in small rivers of the Seversky Donets and the Tuzlov River Basins using biotic indicesThe restructuring of the coal mining industry, which began in the 1990s, has impacted the environmental situation in Eastern Donbass within Rostov Region rather adversely. Aquatic ecosystems of rivers with low water content and, consequently, low dilution capacity are characterized by high susceptibility to anthropogenic impact. Samples of macrozoobenthos were taken in the areas with different anthropogenic load in 18 sections of small rivers of the Seversky Donets and Tuzlov River Basins: the upper reaches, the places downstream of mine drainage water outlets, and mouths. Based on a comparison of the values of the Woodiwiss, Parele, Goodnight–Whitley, and Mayer biotic indices, sections with different levels of water pollution have been identified in these three areas. Water was characterized as “clean” in 47 % of the sections according to the Goodnight–Whitley index, and in 27 % according to the Parele index. The greatest overlap in the estimation of water pollution level according to these indices was in the “polluted” category. Altogether 62 % of the river mouth waters, 50 % of the sections located downstream of mine drainage water outlets, and 17 % of the upper reaches are attributed to this level of pollution. According to all water indices, most of the sections are classified as “polluted”, although there is a difference. Thus, 94 % of the sections were “polluted” according to the Mayer index, 89 % of them according to the Woodiwiss index, 47 % according to the Parele index, and only 33 % of the sections were identified as “polluted” according to the Goodnight–Whitley index. The discrepancy in estimation of water pollution by biotic indices has been found in five cases out of eighteen investigated stations. The final score has been assigned according to the index with the most negative result. For Eastern Donbass area, taking into consideration the class of small rivers, their zoological and geographical characteristics, the consequences of restructuring the coal mining industry, and agricultural nature of this region, biotic indices should be considered as indicators of organic water pollution along with the abundance, biomass, and number of the macrozoobenthos taxa.