Water Quality Assessment of Karnaphuli River of Bangladesh Using CCME-WQI Method

Karnaphuli River is one of the largest recipients of industrial effluent among all the rivers in Bangladesh in the last couple of years. The main purpose of this study is to evaluate the suitability of the river water for irrigation, livestock and other uses and to identify the main pollutants affecting the river during its course through the city. Ten Sampling points along with the Karnaphuli river basin was selected for the WQI assessment. The sampling was conducted for a period of one year from May 2021 to April 2022. Canadian Council of Ministers of the Environment (CCME)-(WQI) Water Quality Index was applied for several water quality parameters namely pH, Total Dissolved Solids (TDS), Dissolved Oxygen (DO), Phosphate, Nitrate, Chloride, Total Hardness, Conductivity, Biological Oxygen Demand (BOD), Cd, Cu, Zn, Pb. Irrigation and livestock indices were analyzed based on Canadian Water Quality Guidelines (CWQGs). The study shows that the river water is mostly alkaline and the pH lies between 6.4 -7.8. The DO value varies from 1.8 to 6 ppm and BOD varies from 1.7 to 3.4 ppm. The concentrations of Cu, Cd, Pb and Zn are Cu- (0.108-0.743 ppm), Cd- (0.073-0.281 ppm), Pb- (0.017-0.699 ppm), Zn- (0.012-0.032 ppm) respectively. Based on the index values, the river water quality has been observed as poor and marginal.