Assessment of water quality parameters of the Bangshi River during dry and wet season in Bangladesh

The present study was conducted on the Bangshi River, Savar, Dhaka, Bangladesh with the purpose of assessing some physico-chemical parameters of water during dry and wet season. Physical parameters including water colour, temperature, depth, velocity, transparency and chemical parameters such as pH, DO, free CO 2 , alkalinity and hardness were analyzed. Samples were collected from five different sampling sites during December 2020 to March 2021 and July 2021 to October 2021. The mean values for temperature, depth, velocity, transparency, pH, DO, free CO 2 , alkalinity and hardness were recorded 25.84 and 30.80°C; 216.97 and 344.71 cm,; 5.96 and 6.89 cms − 1 ; 24.86 and 29.90 cm; 8.14 and 7.28; 2.80 and 4.79 mg/L; 17.15 and 54.97 mg/L; 420.56 and 227.36 mg/L; 167.84 and 106.74 mg/L during dry and wet season, respectively. Some of the water parameters exceeded the standard limit. Dark black and light black colour was observed and a strong odour was present during both the seasons. Some water parameters were positively and some were negatively correlated. Seasons had a substantial impact on all water parameters whereas sampling sites had a significant impact on depth, velocity, transparency, DO, free CO 2 , alkalinity, and hardness. Interaction between the effects of seasons and sampling sites had an impact on velocity, pH, DO, free CO 2 and alkalinity. The results of the study revealed that water quality of the Bangshi River was better in the wet season compared to the dry season, and water of the river is not safe for aquaculture and other household purposes.