EN
Studies on the microbiological quality of selected watercourses in the Białowieski Primeval Forest were assumed (Narewka, Orłówka, Hwoźna, Braszcza, Łutownia, Przedzielnia). ln samples of water taken in the years 2010-2015, the numbers of psychrophilic, coliform and Escherichia coli were determined. High organic contamination of all of the studied watercourses, typical of woodland and wetland areas, was confirmed. lncreased microbiological contamination was indicated only for the Orłówka and Braszcza rivers, which suggests an inflow of contaminants from areas inhabited by wild animals and water-logged areas. The poor sanitary quality of waters from the Hwoźna River is most likely connected with the cross-border inflow of contaminants.