State of the Practice Worldwide: Human Health Risk Assessment of Heavy Metals, Nitrate, and Phosphorus in Groundwater in the Context of Ongoing Traditional Rice Cultivation

Abstract An overall assessment of groundwater quality and soils under paddy fields is vital for the sound management of groundwater resources. This study aims to assess human health risks from groundwater contamination in areas of continuous rice cultivation, by analyzing 72 groundwater from Someh Sara, Gilan, Iran. Groundwater and soil samples from beneath paddy fields were analyzed for major ions and heavy metals (HMs), nitrate (NO 3 ), and phosphorus (P). Visual MINTEQ was used as a chemical equilibrium modeling software. The low NO 3 (ranged from 0.01 to 1.88 mg/L) in groundwater was attributed to the anaerobic conditions. The P ranged from 0.001 to 0.089 mg/L. While Cu (ranged from 36 to 62.5 μg/L) and Ni (ranged from 13.5 to 77 μg/L) (only 2.7% of samples) concentrations did not exceed safe drinking water thresholds, Cd (ranged from 11.5 to 22 μg/L) concentrations exceeded the acceptable limit in all groundwater samples. The results of HM exposure underline that all aged groups, especially infants and children are very vulnerable to noncarcinogenic health risks, spotlight the need for careful attention to reducing Cd concentrations in groundwater considered for drinking.