Bacteriological and physicochemical evaluation of water quality at some points on Ergene Meric Basin Corlu Stream

This study evaluates the physicochemical and bacteriological water quality of the Çorlu Stream within the Ergene–Meriç Basin. The research aims to determine the extent of pollution in regional water resources and to identify the contributions of industrial, agricultural, and residential activities to this pollution. Water samples collected from five different stations during the spring and autumn periods of 2024 were analyzed for various physicochemical parameters, including dissolved oxygen, pH, temperature, salinity, turbidity, chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (TSS), total organic carbon (TOC), as well as bacteriological indicators such as coliform bacteria and E. coli. The results indicate that the stream is subject to high levels of organic pollution and uncontrolled bacteriological contamination. Seasonal analyses for April 2024 revealed low dissolved oxygen levels alongside elevated COD and BOD values, demonstrating that the water is heavily loaded with fecal-derived organic pollutants. In November 2024, bacteriological assessments showed partial dilution associated with seasonal precipitation, resulting in a slight decrease in organic and microbial contamination. However, elevated TSS and TOC levels suggest that bacterial proliferation continues and that fecal pollution has not been fully eliminated. Overall, the findings reveal that the Çorlu Stream is not suitable for human-contact uses such as swimming or irrigation due to persistent organic and fecal contamination. These results highlight the need for strengthened regional water management policies, modernization of treatment systems, and stricter control of agricultural and industrial discharges.