Bacterial contamination in the waters of two lake and river systems in NE Poland in relation to the physicochemical properties of water

Abstract

Determination of the sanitary-epidemiological status of waters used for tourism purposes is very important, hence the aim of this research was to determine the sanitary status of various types of surface water used for recreation. The research area included 18 stand s on the Ostróda-Elbląg Canal and 25 on the Augustów Canal. Water samples were taken during the summer period in 2017-2018. Microbiological analyses were performed in accordance with PN-EN ISO standards and included determining the total abundance of such bacteria as E. coli, coliforms, fecal enterococci and P. aeruginosa. In addition, basic physicochemical analyses of water were performed according to standard methods. The presence of indicator bacteria in the water indicates their fecal contamination and possible epidemiological threat. The general average abundance of bacteria for the waters of the Augustów Canal was 1,628,000±784,000 CFU /mL, while for the Ostróda-Elbląg Canal 2,242,800±964,300 CFU /mL. The abundance of E. coli bacteria in the waters ranged from O CFU / 100mL to 6400 CFU/100mL, coliforms from O CFU/100mL to 7,200 CFU/ 100mL, fecal enterococci from O to 5,800 CFU /100mL. The maximum values of these indicators were recorded in lakes. The P. aeruginosa bacteria were isolated only from waters from an artificial section of the river-lake systems, and their abundance fluctuated in the 120-860 CFU /100mL range. Statistical analyses have shown that the abundance of indicator bacteria depends on some physicochemical parameters of water, such as: EC, pH, temperature, total carbon concentration, total nitrogen concentration. Summing up, it can be concluded that the highest values of the abundance of indicator bacteria occurred in lakes. The river sections were characterized by higher values of an abundance of coliforms and E. coli bacteria and the total abundance of bacteria compared to canal waters, which indicates a fresh inflow of pollutants to the tested systems. In tum, the canal sections were the only habitat of P. aeruginosa.