Assessment of River Water Quality During a Religious Mass Bathing Festival at Sangam, Prayagraj

Sangam, the confluence point of sacred Indian rivers Ganga and Yamuna, is an important site for different religious and cultural events. Surface water was collected from Sangam during the religious mass bathing festival, Kumbh Mela, from 10 January to 9 February, 2020 and the samples were investigated for 10 selected physicochemical parameters including chemical oxygen demand (COD), biochemical oxygen demand (BOD) and dissolved oxygen (DO). BOD and DO exceeded the recommended BIS permissible limits. Mass bathing significantly altered 6 of the parameters (p<0.05). The overall weighted arithmetic water quality index (WQI) during the sampling period was 80.07, indicating very poor quality of the river water. The mean WQI during the bath days (95.65 +/- 19.84) was significantly higher (p<0.05) than that for non-bath days (64.49 +/- 14.65). Stepwise multiple linear regression analysis revealed that the observed WQI values were significantly explained by the parameters COD, DO and BOD.