Health risk assessment of nitrate pollution in shallow groundwater: a case study in Changchun New District, China

High concentrations of nitrate in groundwater pose a threat to human health. To quantify groundwater nitrate pollution in China's Changchun New District and evaluate its human health risks, 98 groundwater samples were collected and analyzed. The spatial distribution of groundwater chemical components was variable with concentrations descending from TDS > HCO3 − > Ca2+ > NO3 − > SO4 2- > Na+ > Cl− > Mg2+ > K+ > NO2 − > NH4 +. Notably, NO3 − concentrations ranged from 0.02–492.72 mg/L and averaged 98.62 mg/L. Over 50% of samples exceeded the Quality Standard for Groundwater of China Class III N threshold (20 mg/L). Principal component analysis determined that NO3 contamination was primarily due to the excessive use of fertilizers in agriculture. A human health risk assessment model was used to assess the potential health risks of groundwater NO3 − via drinking water and skin contact pathways. Approximately 90% of adults, 66% of children, and 45% of infants had acceptable health risks in the study area. NO3 − exposure risk in the towns of Longjia and Xiyingcheng was the highest, while urban areas tended to have lower exposures. The health risks of residents, especially minors and infants, were concerned.