Changes in water quality index of Ganges river at different locations in Allahabad

Abstract

We have determined the water quality index (WQI) of post-monsoon water samples with an aim to assess changes in Ganges river at various locations in Allahabad stretch including that from the confluence with river Yamuna. Physicochemical parameters such as temperature, pH, electrical conductivity (EC), dissolved oxygen (DO), total dissolved solids (TDS), major cations e.g. Na⁺, K⁺, Mg²⁺, Ca²⁺, major anions e.g. F⁻, Cl⁻, Br⁻, SO₄²⁻, NO₃⁻, PO₄²⁻ and alkalinity were analyzed by standard procedures. The values obtained were compared with the guideline values for drinking water by Bureau of Indian Standard (BIS) and World Health Organization (WHO). From the measured quantities, certain parameters were selected to derive WQI for the variations in water quality of each designated sampling site. Results showed considerable deterioration in quality of water at some of the sites. WQI of Ganges river water at Allahabad ranged from 86.20 to 157.69 which falls in the range of poor quality of water. Pearson’s correlation matrix was drawn to find possible interrelations among measured water quality parameters. It is shown that WQI may be a useful tool for assessing water quality and predicting trend of variation in water quality at different locations in the Ganges river.