Hydrochemical composition of the water of the Okkerville river

Abstract

Okkervil is one of the small rivers of St. Petersburg, the source of which is located on the territory of the Leningrad Region, and the mouth is within the city of St. Petersburg. The length of the river is 18 kilometers, and in its course it passes through several rapidly developing settlements, including the village of Novosergievka and Kudrovo. The Okkervil River and its coastal zone, both within the city and beyond its borders, are actively used for various purposes, including recreation and amateur fishing. However, like many other rivers flowing through the territories of large cities, the river. Okkervil is subject to diverse anthropogenic pressure, leading to water pollution. Thus, the water quality of this river may not be of adequate quality for use in fisheries and recreational purposes. The main objective of this work is to determine the chemical composition of the waters of the river and to establish its suitability for fisheries and recreational water use. Sampling was carried out during the open water period at three points with different types of anthropogenic load: outside the city, near the village of Novosergievka; at the entrance to the city; and in the residential area, near the Prospekt Bolshevikov metro station. At each point, the main hydrochemical indicators were determined: the concentrations of iron, copper, ammonium ions, phosphates, nitrates and nitrites, heavy metals, as well as the concentration of dissolved oxygen and BOD5. At all sampling points during the research period in the river, the standard values for the content of nitrites, phosphates, iron and copper were exceeded.The results obtained indicate a high level of pollution associated, among other things, with the ingress of untreated storm drains into the river, and untreated and undertreated household waste. The highest level of water pollution was noted at a point located in a residential area. The water here corresponded to the V class of quality (dirty). Both in the spring-summer and autumn periods of the study, the water of the Okkervil River in the other two sections corresponded to III-IV quality class (moderately polluted - polluted). The water quality of the Okkervil River deteriorates from the source to the mouth. In all the studied areas, the river is unsuitable for fisheries and recreational water use.