Determining of microbiological pollution level of Poyrazlar lake

In this research, the microbial quality of the lake was investigated by taking samples from 20 different points at certain intervals between November 2018 and September 2019 from Poyrazlar Lake located within the borders of Sakarya. Microbiological analyzes were carried out by membrane filtration method. Total coliform bacteria, fecal coliform bacteria, fecal streptococci, E. coli and total living count were determined in samples taken at certain intervals and correlated with temperature, pH, total soluble solids, conductivity and dissolved oxygen values. Total viable count between> 6 and <24 cfu / mL, E. coli between> 3 and <13 cfu / mL, fecal coliform bacteria count between> 6 and <24 cfu / mL, total coliform bacteria count> 28 and <288 cfu / mL and the number of fecal streptococcus bacteria was found to be between> 1 and <24 cfu / mL. In the results, the average temperature value of the lake was measured as 17,2 ° C, dissolved oxygen value 2,5 mg/L-1, electrical conductivity value 198,7 µS cm-1and pH value as 7,5. The relationship between the physical parameters of water and the distribution of bacteria was statistically evaluated using SPSS 20. In the results obtained, a positive correlation coefficient of 0,829 between fecal coliform and total dissolved solids at p <0,05 level, and a negative correlation of -0,829 between electrical conductivity and temperature were determined. As a result of the statistical analysis, it was determined that there is a positive correlation with 0,886 between E. coli and the total living amount at the p <0,05 level. Microbiological pollution of the study area has been evaluated according to national and international criteria. When Poyrazlar Lake is evaluated according to the standards of Surface Water Quality Management Regulation, first class in terms of temperature, pH, total dissolved solids, electrical conductivity, fecal coliform was found to be second class in terms of total coliform and fourth class in terms of dissolved oxygen. According to the results obtained from the research, it was determined that Poyrazlar Lake is not polluted in terms of microbiological quality but has values close to the pollution limit. In order not to increase the pollution level of the lake in the future, domestic and animal wastes around the lake should not be mixed with the lake and public awareness should be raised about taking necessary precautions. In addition, other physical and chemical properties of the lake should be investigated in detail.