Hydrogeochemical Assessment of Groundwater Quality in Jharkhand, India

Abstract

Jharkhand sits on one of India's richest mineral deposits, and that geography comes with a cost. This study examines groundwater quality across three industrially active districts - Dhanbad, Bokaro, and Ramgarh - alongside two predominantly agricultural zones, Palamu and Gumla, used here as comparative controls. Between June 2022 and May 2023, we collected 148 groundwater samples from open wells, bore wells, and tube wells at bi-monthly intervals. Samples were tested for 23 physicochemical parameters and eight heavy metals. Water Quality Index (WQI) scores were calculated using the weighted arithmetic method. Results show that 67% of samples from the industrial belt fail to meet Bureau of Indian Standards (BIS) drinking water criteria for at least one parameter. Iron concentration averaged 3.8 mg/L in Dhanbad - nearly four times the permissible limit of 1 mg/L. Arsenic exceeded BIS limits in 23% of Bokaro samples. Fluoride was problematic in Palamu (mean: 2.1 mg/L; BIS limit: 1.5 mg/L), which suggests geological inputs are adding contamination independent of industrial activity. WQI analysis classified 41% of industrial-zone samples as 'poor' and 18% as 'very poor.' Hierarchical cluster analysis separated samples into three hydrogeochemical groups, each with distinct contamination signatures. Coal mining drainage and iron ore processing appear to be the primary drivers of degraded water quality in the eastern districts, while fluoride problems in the west are geogenic