聊城市城郊浅层地下水硝酸盐污染特征与健康风险评估

Pollution Characteristics and Health Risk Assessment of Nitrate in Shallow Groundwater in Liaocheng Suburbs

运用氮、氧双同位素对聊城市城郊浅层地下水硝酸盐进行溯源,基于人类健康风险评估模型评估其健康风险。结果表明:研究区地下水中硝酸盐质量浓度在3.96 mg/L^38.9 mg/L之间,52%的监测点硝酸盐质量浓度超过《地下水质量标准》(GB/T 14848—2017)中Ⅲ类水质限值(20 mg/L);地下水硝酸盐主要来源于化肥中的NH+4,其次为化肥中的NO-3和土壤中N的矿化作用;成年男性、成年女性和未成年人的非致癌风险值均处于可接受风险水平,区域人群硝酸盐暴露风险的主要途径为饮用区域地下水。

Nitrate in shallow groundwater in Liaocheng suburbs was traced to source by using nitrogen and oxygen isotopes,and was evaluated by human health risk assessment model.The results showed that the mass concentration of nitrate in the groundwater of study area was between 3.96 mg/L and 38.9 mg/L.The mass concentration of nitrate in 52%of the monitoring sites exceeded 20 mg/L,the limit of classⅢwater quality in“Standard for groundwater quality”(GB/T 14848—2017).Nitrate in groundwater primarily derived from NH+4 in chemical fertilizers,next from NO-3 in chemical fertilizers and N mineralization in soil.The non-cancer risk values of adult males,adult females and minors were all at acceptable risk levels.The main exposure risk was the drinking groundwater in this area.