蓝田县农村居民饮用地下水中硝态氮污染及健康风险评价

Nitrate Nitrogen Pollution of Drinking Groundwater and Its Health Risk Assessment for Rural Residents in Lantian County,China

在对蓝田县西北地区农村居民饮用地下水硝态氮含量进行测定的基础上,应用健康风险评价模型对饮用地下水硝态氮污染的健康风险进行了分析。结果表明,枯水期(3月)和丰水期(9月)蓝田县居民饮用地下水中硝态氮平均质量浓度分别为12.00和15.81 mg.L-1,部分样品超过GB 5749—2006《生活饮用水卫生标准》中限量值(20 mg.L-1)。随井深的增加,地下水硝态氮含量明显减小,0～20 m井深硝态氮污染最为严重,>60 m深地下水硝态氮含量较低。健康风险评价表明,南部塬区的焦岱镇、史家寨乡以及河谷阶地的普化镇、玉山镇等区域儿童健康风险指数大于1,也有小部分区域成人健康风险指数大于1,属于不可接受范围;北部山区成人和儿童健康风险值均小于1,在可接受范围内。

Based on the measurement of nitrate nitrogen（NO-3-N） contents of the groundwater,which is the source of drinking water of the rural residents in the northwest region of Lantian County,health risk assessment of the pollution was performed using the health risk assessment model available.The measurement shows that NO-3-N concentration in the groundwater was on average 12.00 mg·L-1 in the low-water season（March） and 15.81 mg·L-1 in the high-water season（September） and some of the water samples even exceeded the upper limit of GB 5749—2006（National Standard for Hygiene of Drinking Water） in NO-3-N content.NO-3-N concentration in the groundwater decreased significantly with the depth of the wells,being the highest in the water within the depth of 0-20 m and much lower in the water below the depth of 60 m.The health risk assessment shows that the drinking water in Lantian County is higher in health risk in the Ba river valley and the tablelands in the southern part than in the mountainous area in the north.