Examining the unintended impacts of COVID on water quality: River Ganga, India

The effect of COVID-19 was observed on water quality parameters (WQPs) of river Ganga, and the overall quality of water was analysed with the aid of weighted arithmetic water quality index (WAWQI), which provides a scientific platform for comparison of water quality (WQ) during pre-, during and post-lockdown. The correlation of parameters was also determined to check the spatial variation of parameters among the monitoring stations. Analysis of Variance (ANOVA) was also performed to confirm the impact of lockdown on WQ. In this study, six water quality parameters (Dissolved Oxygen (DO), pH, Biochemical Oxygen Demand (BOD), Electrical Conductivity (EC), Nitrate (NO₃), and Total Coliform (TC)) were reviewed at five monitoring stations (Shuklaganj, Jajmau Bridge, Ranighat, Jajmau Pumping Station, and Bithoor) of river Ganga at Kanpur stretch. Results revealed that NO₃ was well within the permissible limits at all the stations with respect to all the designated classes specified by CPCB. Lockdown helped in the reduction of BOD concentration from 3.4 to 1.7 mg/l, about 50% maximum, at Shuklaganj from Feb-20 to April-20 and at the same time, the study also revealed that DO concentration was escalated at all the monitoring stations at a significant rate up to 54.86%, highest at Shuklaganj downstream. Water Quality Index (WQI) at Ranighat shows a significant reduction of 30.85% as WQI decreases to 76.28 from 99.81. Similarly, diminution of 59.23% in WQI was seen at Shuklaganj with WQI value declining from 96.27 to 60.46. ANOVA reveals that the lockdown has affected BOD and TC significantly as compared to other parameters. However, there is a noticeable improvement in general characteristics at all sites due to the low levels of tourism and industrial activity during COVID. A correlation analysis was also conducted to deduce the degree of association between the WQPs.