Groundwater quality and its impact due to hydraulic fracturing activities around oil and gas drilling sites: A comprehensive study on distribution, correlation, ecological and health risk assessment of heavy metals

Given the propensity of oilfield drilling activities to induce groundwater pollution, particularly in shallow aquifers, a critical evaluation of contamination risk becomes imperative for effective groundwater management and conservation. The distribution of twenty-two physicochemical parameters including heavy metal contamination in water is assessed using heavy metal pollution index (HPI), metal index (MI), and water quality index (WQI), revealing a high level of contamination. HPI values for the PRM season range from 63.3 to 4335.4 (mean: 1166.7) and for the POM season from 5.2 to 47.3 (mean: 23.3). The MI values during the PRM season ranged from 1.1 to 75.7 (mean: 10.1), while POM values ranged from 0.5 to 4.4 (mean: 1.1). The WQI for PRM ranged from 21.4 to 1093.7 (mean: 184.9) and from 18.1 to 614.2 (mean: 82.4) during the POM period. Irrigation quality indices determine groundwater suitability of groundwater for agricultural purposes. Employing multivariate statistical approaches, this study delineates the contributions of both natural and anthropogenic activities to alterations in groundwater hydrochemistry . Hazard Index (HI) values exceeded the USEPA's safe limits in 99% of PRM samples for children and 100% for adults, while 27.3% of POM samples for children and all POM samples for adults also surpassed safe levels. Carcinogenic Risk (CR) assessment indicated arsenic, chromium, mercury, nickel, and lead concentrations exceeding the USEPA's threshold of 1.0 x 10⁻⁶, suggesting significant carcinogenic risks for both adults and children. The study uses Monte-Carlo simulation to examine human health risk assessment parameters, and advocates for strategic planning, water resource management , and treatment schemes to mitigate identified health risks and towards providing safe drinking water . • Investigated groundwater contamination, risks, and sources across wet and dry seasons, providing a holistic temporal perspective. • Uncovered that produced water from abandoned drilling sites contains high levels of Potential Toxic Elements (PTEs). • Utilized spatial maps to assess seasonal variations, health risks, pollution status, and potential sources of elements effectively.