The article discusses pollution characteristics in natural waters and reasons for fluctuations in their levels of surface waters. The samples were collected in the city and region of Vilnius, i.e. the places where industry objects that may affect the quality of surface water bodies are mainly erected. The obtained results have revealed that the highest demand for biochemical oxygen (BOD) in the Vilnia river over the whole period have reached 32.3 mg/l in June, for dissolved oxygen (O2) –10.63 mg/l O2 in winter and for the concentration of suspended solids (SS) –53.44 mg/l in April. The results of the annual main concentration characteristics of pollution in the Vilnia river over the investigation period have been compared with assessment criteria for evaluating an ecological status of water.

Article in Lithuanian