Abstract:
As the most common pollutant in global water resources, the identification of the main controlling factors and sources of NO
3− is crucial to the control of NO
3− pollution. Based on methods such as human health risk model, random forest model, isotope and MixSIAR model, this study analyzed the distribution characteristics and potential risks of shallow groundwater NO
3− in Huazhou District, and revealed the main controlling factors and main sources of shallow groundwater NO
3−. The results show that the shallow groundwater NO
3− concentration in Huazhou District is high in the west and low in the east, especially in the southwest. The NO
3− concentration is as high as 271 mg/L. The main factors controlling NO
3− concentration being EC>ORP>Ca
2+>Mg
2+>T>TDS>HCO
3−. The main sources of NO
3− are soil nitrogen and manure & sewage. The manure & sewage contributes the most to the NO
3− content (63.8%), followed by soil nitrogen (19%) and chemical fertilizer (12.7%). Long-term drinking of shallow groundwater with high NO
3− concentration in the study area has potential risks to human health, especially for children, whose HHRA assessment risk is as high as 7.904.