Characterizing the Pollution Sources and Ecological Water Quality of the Tropical Rivers, India: A Comparative Study of the Bhagirathi-Hooghly, Jalangi, and Mathabhanga-Churni Rivers

The present study has been carried out on the water qualityWater quality assessment of the three selected rivers with 10 sampling sites: Bhagirathi-Hooghly, Jalangi, and Mathabhanga-Churni located in the tropical region of India. The quality has been assessed based on the concentration of 14 parameters, two general water qualityWater quality indices and two other ecological water qualityWater quality indices. The results from samples (N = 120) indicate few valuable insights on the spatial and seasonality of the water qualityWater quality. Particularly, the Jalangi and Mathabhanga-Churni Rivers are highly vulnerable due to very low dissolve oxygen (<3 mg l–1) and high organic pollutionOrganic pollution (Fig. 8.5). WQIWater Quality Index (WQI) represent Bhagirathi-Hooghly (WQI range:63.71 for BH1-68.94 for BH5) river as poor and Jalangi and Mathabhanga-Churni as poor to very poor water qualityWater quality (WQI range:73.355 for JK-90.64 for MC1). Similarly, the OPI indicates high organic pollutionOrganic pollution in the upper stretch of the Mathabhanga-Churni and moderate pollutionPollution for Bhagirathi-Hooghly. The HCA and discriminant analysis have also confirmed the significant difference of water qualityWater quality between Bhagirathi-Hooghly and Mathabhanga-Churni. The causes of this phenomena have also been discussed from the natural and human induced point and non-point sources of pollutionPoint and non-point sources of pollution. The discharge variation is the crucial natural factor while discharge of wastewater from industries, urban and agricultural runoff are the major causes of water pollutionPollution.