Characterization and Health Risk Assessment of Nitrate Pollution in Groundwater in Jingbian Plain, China

Long-time anthropogenic activities have increased the pollution level in groundwater, especially NO3− concentration, in the Jingbian region. However, investigations and studies on NO3− concentration in groundwater and its health risks to human body were limited. Therefore, this study collected water samples from phreatic and confined aquifers to analyze the groundwater hydrogeochemical characteristics and spatial distribution of NO3−, and its health risk to humans. The results show that confined and phreatic aquifers had the same hydrochemical type (HCO3− Ca Mg type), and the rock action shaped the groundwater evolution. The phreatic water with high NO3− concentrations were mainly distributed in the southwest and northeast, and the confined water was mainly distributed in the south of the study area, respectively. The NO3− pollution in confined water was less than that of those observed for phreatic. Moreover, the health risk from phreatic was greater than from confined water, while NO3− pollution posed less risk to children than adults. The areas for phreatic of the unacceptable hazard quotient (HQ) values of children and adults were 27.12% and 4.94% of the study area, respectively; and for confined of the unacceptable HQ values of children and adults were 22.01% and 0.09%, respectively. Different measures, such as proposing reasonable policies, exploring efficient remediation technologies, long-term monitoring, scientific agricultural production, controlling pollutant discharge, etc., must be implemented to protect groundwater resources and reduce the harm risk to human health.