Bacteriological studies of water and bottom sediments of the Vistula River between Wyszogrod and Torun

This paper deals with the sanitary conditions of the water and bottom sediments in the Lower Vistula river, between Wyszogród and Toruń. The contaminationextent of the water and bottom sediments by easily decomposable organic matter and substances of faecal origin have been indirectly estimated by determining the total number of heterotrophic bacteria (TVC 20oC) and the occurrence of the faecal coliform (FC) and faecal streptococci (FS). Examination resultsenabled a classification of this water as moderately and moderate highly affected by the easily decomposable organic matter and faecal substances. The bottom sediments, however, contained a much greater load of psychrophilic and faecal heterotrophic bacteria, yet they were polluted to a moderate extent. According to bacteriological results the examination site that revealed the greatest extent of easily decomposable organic matter and faecal matter, both in the water and bottom sediments, was the study site near Płock (site II). The least affected sites were those in the Włocławski Reservoir dam (site III) and near Nieszawa (site IV). The faecal contamination factor (FC:FS ratio), in majority cases being more than 4, indicated that it was human-borne faecal contamination that dominated the area.