DISTRIBUTION OF NITROGEN IN THE SHALLOW GROUNDWATER OF WEST LIAOHE RIVER PLAIN AND HEALTH RISK ASSESSMENT

In this study, the contents of nitrogen as NH₄⁺, NO₂^- and NO₃^- in groundwater samples of West Liaohe River Plain are tested to assess health risk with non-carcinogenic risk model. The results show, compared with the limiting value of Groundwater Quality Standard (GB14848-2017), the exceeding rate of nitrate nitrogen is 8%, mainly distributed in the southeast and southwest of the study area. The exceeding rate of ammonia nitrogen is 10%, mainly distributed in the center and south of the area. The water quality of Class Ⅰ, Ⅱ and Ⅲ accounts for 83%, and Class Ⅳ and Ⅴ for 17% of the total groundwater. The total non-carcinogenic risk index and total carcinogenic risk index of nitrogen in groundwater samples are both lower than the health risk assessment standard recommended by the United States Environmental Protection Agency. On the whole, the pollution degree of nitrogen in the study area is relatively light, and the nitrogen pollution is mainly distributed in the human activity concentrated area. The health risk assessment can provide a technical reference for monitoring and control of nitrogen pollution in groundwater of the area.