Groundwater quality evaluation and human health risk assessment of nitrate using deterministic and probabilistic approaches in Qorveh-Dehgolan region, Kurdistan province, Iran

This study evaluated groundwater nitrate contamination and associated non-carcinogenic human health risks for infants, children, teens, and adults in Qorveh-Dehgolan region, Kurdistan province, Iran. Analysis of 51 groundwater samples revealed that nitrate concentrations varied from 6.20 to 99.20 mg/L, with 3.92% of samples exceeding the threshold value of 50 mg/L. Health risk was evaluated using both deterministic and probabilistic approaches under two exposure scenarios: oral ingestion and dermal contact. Deterministic analysis results indicated that hazard quotient (HQ) values for the oral ingestion exceeded safe levels for infants (7.84%), children (25.49%), teens (7.84%), and adults (3.92%), with children being the most vulnerable. In contrast, probabilistic analysis showed that only infants had a 95th percentile HQ slightly above 1 (1.0437), and the other population groups remained within safe limits. The HQ values for dermal contact indicated no potential health risk. Correlation and variance attribution analyses identified nitrate concentration, exposure duration, and event duration as key parameters affecting uncertainty in HQ estimates. Overall, the findings of the study demonstrated that the oral ingestion of groundwater, as a primary exposure scenario, may pose potential health risk, particularly to infants and children. Accordingly, the implementation of appropriate management strategies is essential to mitigate this risk.