Probabilistic Health Risk Assessment of Heavy Metals in Groundwater From an Industrial Area of Bengaluru: Deterministic, Probabilistic, and Scenario Modeling Approaches

Pollution of groundwater by heavy metals poses a serious health hazard to human beings. This study evaluates the noncarcinogenic and carcinogenic risks of the following five metals: lead (Pb), chromium (Cr (VI)), cadmium (Cd), copper (Cu), and iron (Fe) in groundwater at 30 stations in the Bellandur industrial area of Bengaluru, India. The concentrations of groundwater metals were determined at these 30 stations, and the hazard quotient (HQ), hazard index (HI), and lifetime cancer risk (LTCR) were calculated according to USEPA standards. Probabilistic risk was measured using Monte Carlo simulation. Reductions of 20% and 50% were assessed by scenario modeling. The metal analysis shows that the exceedance percentages with respect to Pb, Cr (VI), Cd, and Fe are 33.33 53.33, 53.33, and 63.33, both with respect to Bureau of Indian Standards (BIS) and World Health Organization (WHO) as they both use the same permissible limits, while Cu exceeds the BIS Limits by 36.67%. However, WHO has not placed any minimum limits for Cu and only an upper limit of 2 mg/L, as per which none of the stations exceed the limits. Results show widespread exceedances, especially among children, where Pb is the dominant contributor to noncarcinogenic risk, while Cr (VI) is the sole driver of carcinogenic risk. HI exceeded 1 at 20 stations for adults and 21 stations for children. LTCR exceeded 1 × 10−4 at 19 adult stations and 16 child stations. The marginal stations that showed compliance only under 50% reduction were illustrated in the scenario model. Pb, Cr (VI), and Cd are identified as the chief drivers of health risks in the region. Targeted remediation and policy interventions are urgently needed. Probabilistic modeling and scenario analysis offer robust tools for groundwater risk governance.