Pollutions of watercourses

The article discusses issues related to the pollution of watercourses, and an analysis of various aspects of this topic has been carried out: sources of pollution, types, effects and methods of counteracting. The issue of watercourse pollution is described on the example of the situation on the Oder in 2022. Rivers play a key role for both the natural and anthropogenic environment. Used by industrial sectors that heavily exploit the aquatic environment, they are exposed to the emission of pollutants in many forms. The deterioration of water parameters affects the development of harmful microorganisms, the presence of which puts an additional burden on watercourses. In addition, the natural migration of water on the surface of the Earth's crust facilitates the free migration of low-quality water along with harmful substances. In Poland, between 2014 and 2019, more than half of the rivers studied, i.e. as much as 63.1%, were classified as waters of moderate quality class, thus not allowing them to be fit for consumption. The analysis was carried out on the basis of a literature review and reports published by the Institute of Environmental Protection and the Chief Inspectorate of Environmental Protection, which show that one of the main problems of the environmental disaster on the Oder was the increased electrical conductivity of water, exceeding 7000 μS/cm, and the increased pH, which was the result of contamination of the river with poorly treated post-mining wastewater. The persistently high salinity of the water created conditions conducive to the bloom of Prymnesium parvum algae  capable of producing a strong toxin called primnesin. The release of primnesin into the aquatic environment as a result of the death of microorganisms and the associated reduction in oxygen content in the water led to the mass death of fish, estimated at 360 tonnes, including protected species.