Assessment of Water Quality Status and Heavy Metals Contamination in River Kali-East, India using Pollution Indexes and Health Hazards

Abstract

River Kali-East is one of the intermittent rivers of the Indo-Gangetic plain flowing actively in the monsoon season in western Uttar Pradesh, India. Every day, the river receives a significant amount of untreated and partially treated wastewater from various industries and sewage systems in different municipal areas through which it passes. Therefore, the river is heavily polluted with various organic and inorganic contaminants, rendering it unsuitable for drinking, outdoor bathing, fish culture and agricultural irrigation. Considering the physicochemical parameters of pre-monsoon season, acidic pH, less DO, high BOD, COD, TDS, TN, sulfate, phosphate, potassium and chloride ions were observed as compared to the post-monsoon season. Simultaneously, the overall mean values of heavy metals (HMs) concentration in pre-monsoon season were also observed beyond the permissible limit as per the Bureau of Indian Standards (BIS). The concentrations of HMs in both seasons were found in order of Fe > Zn > Mn > Ni > Pb > Cu > Cd > Cr. Continuous discharge of industrial and domestic wastewater over an extended period is the main cause of the elevated levels of HMs in the riverine ecosystem. Further, for the identification of the main sources of pollution load and related health risks, the assessment of the water quality index (WQI), heavy metal pollution index (HMPI), geo accumulation index (Igeo) and principal component analysis (PCA) were also performed. The results of the physicochemical analysis, HMs and WQI indicated that the river Kali-East is extremely polluted at all the sampling locations, which could significantly threaten human health and the environment. The outcome of WQI, HMPI, Igeo and PCA confirmed that both temporal and spatial changes occurred during pre- and post-monsoon seasons.