Water quality assessment of Ganga River along its course in India

The water quality characteristics of the river Ganga were examined in this study in order to create a water quality profile based on the method developed by the National Sanitation Foundation, United States of America and amended by the Central Pollution Control Board, India. CPCB has classified surface water into five different categories i.e. A, B, C, D, E, on the basis of water quality index. As per CPCB standards, "A" and "B" lie under non-polluted, "C" comes under the polluted category, whereas "D" and "E" come under the heavily polluted surface water category. WQI is a function of pH, dissolved oxygen, biochemical oxygen demand, faecal coliform. 26 sampling stations were selected across the course of the river Ganga throughout India. The data used in the study was obtained from the archives of the Central Water Commission, India. The various physico-chemical parameters like pH, dissolved oxygen, biochemical oxygen demand, faecal coliform, and total dissolved solids were analysed. Out of 26 stations, 6 stations were in class A, 1 station in class B, and 19 stations were in class C. The average value of the Ganga's water quality index was found to be 47.37, and it falls in category C (polluted). In order to understand the interplay between different water quality metrics, the Karl Pearson correlation matrix was calculated, and faecal coliforms were found to be correlated with pH, turbidity, and biochemical oxygen demand.