In Nepal, water in many rivers is being polluted by the industrial effluents. In the present study, water from seven sites in the Narayani River was analyzed for various physico-chemical parameters like pH, temperature, conductivity, turbidity, total suspended solids (TSS), dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD) and total alkalinity. Similarly, the amount of ammonium-N, nitrate-N, nitrite-N, total phosphate, sulphate, sodium, potassium, calcium, magnesium, iron, manganese, zinc, lead, copper and boron were also determined. Based on the volume of the effluents, discharged by the industries into the Narayani River, the most polluting industry is the pulp and paper industry. Results showed that the water in the river gets polluted after receiving the effluents from the paper industry and again it becomes free of pollutants downstream. Some of the parameters remained relatively uniform throughout the stretch of the river whereas the values of pollution indicating parameters such as pH, conductivity, suspended solids, alkalinity, some nutrients and heavy metals were higher near Gaindakot, just after the input of paper industry effluents. This study concludes that there is the need for proper treatment of industrial effluents before discharging them into the river.
