基于^(15)N的地下水中硝酸盐污染源解析:以陡河流域为例

Source Apportionment of Nitrate in Groundwater Based on ^(15) N:a Case Study in Douhe Basin

地下水中硝酸盐污染源解析是区域地下水污染调查评价的重要内容,也是地下水资源管理的重要依据。以陡河流域为例,采用野外采样测试和室内分析的研究方法,结合地下水中15N同位素技术识别地下水中NO3污染的来源及其贡献比。研究结果表明:地表水中N来源于沿岸化粪系统排泄物,地下水中N来源于动物粪便和化肥的混合;远离河岸带农灌区地下水中硝酸盐主要来源为化肥,贡献比例从50%~72%不等,远离河岸带居民区地下水中硝酸盐主要来源为粪便,贡献比例从42%~80%;河岸带地下水中硝酸盐主要来源于河水入渗,但普遍存在反硝化现象。

Source apportionment of nitrate in groundwater is an important issue in regional groundwater contaminantion survey and basement for the groudwater management. Douhe Basin had been seleceted as the study area,field survey and sampling works have been done,and the source identification has been done based on15 N concentration in groundwater,and the results show that,the nitrate from septic tanks is the main source of that in surface water,the mixed nitrate from fertilizer and animal wastes are the main sources of that in groundwater; in the aggricultural irrigation area far away from river,fertilizer is the main source and its proportion could range from 50% to72%,the residential area far away from river,the feces is the main source and its proportions range from 42% to80%; the nitrate are mainly from surface water infiltration in riverbank area,and denitrification is a common process in these areas.