Microbial and chemical quality assessment of the small rivers entering the South Baltic. Part II: Case study on the watercourses in the Puck Bay catchment area

Due to its location, Puck Bay is an area particularly vulnerable to pollution of anthropogenic origin. The aim of the study was to assess the water quality of small watercourses entering the inner part of Puck Bay. The paper presents the results of chemical and microbiological analyses of 10 rivers and canals at their estuaries located on the western shore of the internal Puck Bay. The following environmental parameters were analyzed: conductivity, pH, dissolved oxygen concentration (in situ measurements), COD (cuvette tests), concentrations of ions (ion chromatography). Microbiological analysis included assessment of sanitary condition based on the number of fecal coliforms by a cultivation method. The determination of basic microbiological parameters such as: prokaryotic cell abundance expressed as total cells number (TCN), prokaryotic cell biovolume expressed as average cell volume (ACV), the prokaryotic biomass (PB) and prokaryotic cell morphotype diversity were determined using epifluorescence microscopy method. Based on the obtained results, it was found that small watercourses may carry a notable load of anthropogenic pollution and thus affect the environment of Puck Bay. The results clearly indicate the need for quality monitoring in the rivers and canals in the Coastal Landscape Park, flowing into Puck Bay. The research showed that also smaller watercourses may have an impact on the coastal waters' state, and thus on the Baltic Sea water quality.