摘要
硝酸盐(NO_3^-)是北京地下水的主要污染物之一。本文分析了永定河冲积扇不同部位第四系地下水的水化学和氮、氧同位素特征,识别了地下水中NO_3^-的主要污染源,并定量评价了各种源的贡献。研究区地下水的NO_3^--N浓度介于1.32~37.44 mg/L,80%的地下水样NO_3^--N浓度超过我国《生活饮用水卫生标准》(20 mg/L)。地下水的δ15N-NO_3^-值介于+9.38‰^+16.96‰,均值12.87‰,δ18O-NO_3^-值介于+3.13‰^+21.18‰,均值+10.39‰,结合反硝化作用的识别,推断地下水中NO_3^-主要来自粪肥,部分来自NO_3^-化肥和大气降水。采用氮、氧同位素和物质平衡混合模型定量评价表明,粪肥对地下水NO_3^-的贡献为58%~81%,据此提出了保护和改善地下水水质的建议。
Nitrate （NO3） is one of the main contaminants in groundwater in Beijing. In this study, the char- acteristics of hydrochemistry, nitrogen isotope （18N-NO3-） and oxygen isotope 18O-NO3-） in different parts of the quaternary groundwater are analyzed in the Yongding River alluvial fan. The contaminant sources of NO3- in the groundwater are identified, and the contributions of these different contaminant sources to the NO3-are evaluated quantitatively. The concentrations of NO3-N in the groundwater range from 1.32 mg/L to 37.44 mg/L, The concentrations of NO3--N in 80% of the groundwater samples exceeded the drinking water standarnd of 20 mg/L. The values of 18N-NO3- in groundwater range from ＋9.38‰ to ＋16.96‰ and the mean value is ＋12.87‰. The values of18O-NO3- in groundwater range from ＋3.13‰ to ＋21.18‰ and the mean value is ＋ 10.39‰. Combined with the identification of denitrification in groundwater, NO3-mainly come from manure and partly come from chemical fertilizer and precipitation. Quantitative evaluation with isotope techniques and material balance model shows that manure contributes 58%~81% to the concentra- tion of NO3- in groundwater. On the basis of this study, the suggestion about how to protect and improve groundwater quality is recommended.
出处
《水利学报》
EI
CSCD
北大核心
2016年第4期582-588,共7页
Journal of Hydraulic Engineering
基金
北京市科技计划项目(D07050601510000)
关键词
地下水
硝酸盐
同位素技术
污染源
groundwater
nitrate
isotope technique
contaminant source
