Assessment of the ecological status of the surface waters of small rivers of the Western Bug (Zakhidnyi Buh) river basin on the degree of pollution (on an example of the Gapa river)

Abstract

Goal. To assess the condition of surface waters of the Gapa river by the level of pollution. Methods. Overall assessment of the level of pollution of the waters of the river was carried out using the method of calculating the rate of pollution. The value of the coefficient of pollution describes the concentrations exceeding the standards in fractions of maximum permissible concentration. Using the obtained numerical values of the coefficient of pollution it is possible to assess the state of water pollution. It is established that throughout the period of research, deviations from the norms of maximum permissible concentrations are traced in the following indicators: biological oxygen demand (BOD5), the content of ammonium, nitrite, phosphorus, manganese, total iron. The study is based on the average values of hydrochemical parameters for the period of 2014–2018 on the approved point of state monitoring over the quality of water of the Gapa river (2 km upstream from the mouth of the river, below the lake Yahodynske). Results. On the basis of generalization, systematization, and analysis of the results of routine observations of service monitoring over surface water quality assessment is made of surface water of the Gapa river by the level of pollution. It is determined that the greatest impact on the functioning of the river ecosystem provides the human factor, disrupting the natural state of the watercourse, bringing unusual elements that directly degrade its quality. Conclusions. It is established that the condition of the water in the Gapa river for the level of pollution now corresponds to class III of quality that characterizes the surface water as «moderately polluted». Determination of the level of water pollution of the Gapa river is of great importance for the assessment of the environmental health situation in the basin of the Western bug river, the main directions of water protection, improvement of the ecological status of each water body and the establishment of environmental standards of water quality.