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    河北新生代玄武岩地下水中硝酸盐成因及健康风险评价

    Spatial distribution, origin, and health risk assessment of nitrate in groundwater of Cenozoic basalts in Zhangbei county, Hebei Province

    • 摘要:研究目的】为了判别河北省新生代玄武岩地下水中硝酸盐成因及其带来的健康风险。【研究方法】本文选择张北县玄武岩分布区,利用45组地下水水化学及氢氧稳定同位素数据,识别了区内地下水中硝酸盐分布特征及成因,并针对氮污染问题开展了地下水硝酸盐的健康风险评价。【研究结果】研究区地下水中硝酸盐平均浓度为86.08 mg·L-1,26.6%的采样点NO-3质量浓度超过GB/T 14848-2017《地下水质量标准》中III类地下水硝酸盐限量值(20 mg·L-1);不同土地利用类型条件下地下水中硝酸盐含量差异较大,其中城镇区地下水中硝酸盐质量浓度最高,水浇地次之,林草地和旱地最小。区内地下水硝酸盐的主要来源为牲畜粪肥及生活污水混合入渗,其次为农业化肥淋滤。基于健康风险评价模型,成人和儿童通过饮水摄入硝酸盐的健康风险较高,占总健康风险贡献率的99.23%,远大于皮肤接触途径。其中儿童经饮水摄入和皮肤接触两种途径的健康风险均显著高于成人,75.55%的采样点地下水硝酸盐对儿童的健康风险超出了可接受水平。【结论】从供水安全角度,建议对高风险地区增加净水设备降低人体健康风险。

       

      Abstract: Objectives In order to identify nitrate sources and health risks in groundwater of Cenozoic basaltic rock in Hebei province.Methods The basalt distribution region in Zhangbei county is selected as a typical study area. Based on hydrochemistry and isotopes data of 45 groups groundwater samples, the distribution characteristics and origin of nitrate in basalt groundwater were studied, the health risk of nitrate in groundwater was evaluated using the health risk assessment model.ResultsThe results showed that the average concentration of nitrate in the groundwater of the study area was 86.08 mg·L-1, The nitrate concentration of 26.6% of the sampling sites exceeded the limit value of the III grade groundwater quality in GB/T 14848-2017《The Quality standard of Underground Water》 (20 mg·L-1);The nitrate pollution of different land use types varied greatly, and the content of nitrate in urban areas was the highest, followed by irrigated land,with forests、grasslands or dry land not exceeding the standard.The sources of nitrate in groundwater was mainly manure and domestic sewage, and the next was chemical fertilizer leaching;The health risks of nitrate exposure through skin contact among the population in the study area were at acceptable levels, while the health risk of nitrate intake from drinking water was higher, and the contribution rate of nitrate intake from drinking water accounted for 99.23% of the total risk, which was much higher than that from skin contact route.The health risks of drinking water intake and skin contact in children were significantly higher than those of adults.The health risks of groundwater nitrates to children in 75.55% of the sampling sites exceeded acceptable levels.Conclusions From the perspective of water supply safety, it is recommended to increase water purification equipment in high-risk areas to reduce human health risks

       

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