PRE AND POST-MONSOON ASSESSMENT OF HEAVY METAL POLLUTION IN WATER OF RIVER GOMATI, MIDDLE GANGA BASIN

Rivers are vital to human civilization but are increasingly threatened by pollution from industrial, agricultural, and domestic sources. The Gomati River, a major tributary of the Ganga in Uttar Pradesh, India, has experienced severe degradation due to rapid urbanization, industrial discharge, and poor wastewater management. This study evaluates heavy metal contamination and water quality variations along the Gomati River and its key tributaries during pre- and post-monsoon seasons of 2022. Water samples were analyzed for Fe, Ni, Cu, Zn, and Cd concentrations using Atomic Absorption Spectrophotometry, and multiple pollution indices: Metal Index (MI), Degree of Contamination (C ), d Heavy Metal Pollution Index (HPI), and Nemerow Pollution Index (NPI) were applied to assess contamination levels. Multivariate statistical tools, including Pearson correlation and Hierarchical Cluster Analysis (HCA), were used to identify inter-metal relationships and pollution sources. Results show that Cd, Ni, and Cu concentrations exceeded permissible limits at several sites, with contamination increasing downstream and peaking in the Sai tributary due to industrial and urban effluents. Pre-monsoon samples exhibited higher metal concentrations due to lower dilution and higher evaporation. Correlation and cluster analyses indicated a common anthropogenic origin of contaminants, while Caboi diagrams revealed near-neutral pH conditions favoring metal accumulation in sediments. Overall, the Gomati River system is classified as severely to critically polluted. Effective management strategies such as stricter regulation of effluent discharge, improved sewage treatment, sustainable agricultural practices, and continuous monitoring are essential to restore the ecological integrity and water quality of the Gomati River.