HYDROCHEMICAL ANALYSIS AND FEATURES OF THE USE OF THE SURFACE WATERS OF THE OKONKA RIVER

Abstract

In modern conditions, there is a significant increase in anthropogenic impact on the basins of small rivers, which leads to a rapid deterioration of their ecological state. Therefore, it is necessary to constantly analyze and monitor of the quality of surface waters, as well as the peculiarities of their use in order to identify deviations and protect against negative impacts. The study was carried out on the basis of methods of collecting and analyzing statistical and cartographic information, materials from a survey of the state of the Okonka River basin, potentiometric and photometric analysis of determining the content of nitrogen compounds in surface waters, as well as studying the peculiarities of water use. The Okonka River flows through the territory of the Manevitsky district of the Volyn region. It belongs to the river basin. Styr and its left tributary of the first order. The length of the river is 30,7 km. There are two nature protection objects in the river basin: Okonski Dzherela and Lake Glybotske. For hydrochemical studies, water samples were taken at four locations in the period of 2016–2018: 1 – Okonka river 15 km from the source; 2 – the Okonka river mouth; 3 – river Pidgorodets estuary; 4 – river Chernyavka estuary. A tendency to an increase in the content of nitrites in water samples was established in all studied periods, except for the winter of 2017 and 2018. The highest rates were observed in autumn, and the lowest in winter, but they were within the normal range. Water resources are currently used sparingly. The development of the river basin is not high. Within its framework, 16 settlements are located. Basically, water is taken for household and drinking use and for fisheries. The total demand for water is 3,907 thousand m³ per year, and the irretrievable use is 900 thousand m³. Exceeding the norms of hydrochemical indicators was not recorded. The content of specific toxic substances has noticeably increased, although their indicators do not exceed the norm. In general, the ecological state of the Okonka River Basin is satisfactory.