Effect of Seasonal Changes on Physicochemical Properties and Pollution Levels of the Dakatia River in Chandpur, Bangladesh

An essential body of water close to Chandpur, Bangladesh, the Dakatia River plays an essential role to the local ecosystem and socioeconomic life. Seasonal fluctuations are important water quality indicators, such as temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), and hardness, which are examined in this study. In accordance with the Environmental Conservation Rules (ECR, 2023), water samples were taken during the four seasons of winter, summer, rainy season, and pre-winter. Significant seasonal changes are indicated by the results. Winter water temperatures were 21.6°C, while rainy season temperatures were 28.7°C, all falling within the acceptable range of 20–30°C. During the wet season, the pH stayed within the permissible range of 6.5 to 8.5, ranging from 7.3 in the pre-winter to 8.2. The needed criterion (≥5 mg/L) was met by DO levels, which were highest in the summer (8.9 mg/L) and lowest in the pre-winter (5.9 mg/L). Moderate seasonal changes were observed in the EC and TDS readings, which remained well within acceptable bounds. BOD and COD readings remained below the statutory threshold, indicating mild organic contamination. Summer had the maximum hardness (67.6 mg/L), and pre-winter had the lowest (49.8 mg/L), indicating seasonal variations in mineral concentration. The Dakatia River's water quality is generally within safe limits; however, seasonal fluctuations show the impact of hydrological changes. To avoid possible deterioration and guarantee sustainable water quality for nearby communities and aquatic life, ongoing monitoring and management techniques are required.