大同盆地地下水硝酸盐分布特征及来源解析  

Distribution characteristics and source analysis of nitrate in groundwater of Datong Basin

作　　者：葛勤 张俊朋 汪洋 王袆曼 邵政 李翔 刘海燕 李昕妍 GE Qin;ZHANG Jun-peng;WANG Yang;WANG Hui-man;SHAO Zheng;LI Xiang;LIU Hai-yan;LI Xin-yan(School of Water Resources&Environmental Engineering,East China University of Technology,Nanchang 330013,China;Jiangxi Province Key Laboratory of the Causes and Remediation of Groundwater Pollution,Nanchang 330013,China;Jiangxi Coalfield Geological Prospecting Research Institute,Nanchang 330001,China)

机构地区：[1]东华理工大学水资源与环境工程学院,江西南昌330013 [2]地下水污染成因与修复江西省重点实验室,江西南昌330013 [3]江西省煤田地质勘察研究院,江西南昌330001

出　　处：《中国环境科学》2025年第2期1004-1015,共12页China Environmental Science

基　　金：国家自然科学基金资助项目(42202288,42262029);江西省自然科学基金资助项目(20212BAB213007,20232BAB203066);江西省水利厅科技项目(202425YBKT31)。

摘　　要：利用水化学分析和多同位素联合技术(δ^(18)O-H_(2)O、δ^(15)N-NO_(3)^(-)和δ^(18)O-NO_(3)^(-)),研究大同盆地地下水硝酸盐来源及转化过程,借助MixSIAR模型定量解析各污染源的贡献率.结果表明,地下水中NO_(3)^(-)-N、NO_(2)^(-)-N和NH_(4)^(+)-N平均浓度分别为32.07,0.96,0.61mg/L,以NO_(3)^(-)-N为主,最高浓度达538.61mg/L,超过地下水质量(GB/T 14848-2017)Ⅲ类标准(20mg/L)27倍,超标率达39.13%;垂向上,地下水NO_(3)^(-)-N浓度随井深增加而降低,即浅层地下水(均值34.26mg/L)>中层地下水(22.05mg/L)>深层地下水(13.07mg/L).硝化作用是地下水氮转化的主要机制,反硝化作用不明显.污水粪肥、土壤氮和化学肥料是造成地下水硝酸盐污染的主要原因,其平均贡献率分别为浅层地下水:污水粪肥(33.6%)>土壤氮(33.5%)>化学肥料(21.5%),中层地下水:污水粪肥(43.3%)>土壤氮(34.4%)>化学肥料(18.1%),深层地下水:土壤氮(54.4%)>化学肥料(25.1%)>污水粪肥(18.5%),不确定性分析表明化学肥料和土壤氮的不确定性指数UI90值较高,对硝酸盐污染的贡献率表现出较大的不确定性.研究成果为地下水氮转化和污染来源解析提供参考依据.This study delved into the origins and transformation processes of nitrate in the groundwater of the Datong Basin,utilizing hydrochemical analysis alongside multi-isotope techniques(δ^(18)O-H_(2)O,δ^(15)N-NO_(3)^(-)andδ^(18)O-NO_(3)^(-)).With the MixSIAR model,we quantitatively assessed the contribution of various pollution sources.Research results are as follows,the mean concentrations of NO_(3)^(-)-N,NO_(2)^(-)-N and NH_(4)^(+)-N in groundwater were found to be 32.07,0.96和0.61mg/L,respectively,with NO_(3)^(-)-N being the most prevalent.Remarkably,the peak concentration of NO_(3)^(-)-N soared to 538.61mg/L,surpassing the Class III groundwater quality benchmark(20mg/L)by a staggering 27 times,with a 39.13%exceedance rate.The NO_(3)^(-)-N concentration decreased as groundwater depth increased:shallow groundwater averaged at 34.26mg/L,middle groundwater at 22.05mg/L,and deep groundwater at 13.07mg/L.Nitrogen transformation in groundwater was primarily driven by nitrification,whereas denitrification played a minor role.The primary culprits behind nitrate pollution in groundwater were identified as sewage and manure,soil nitrogen and chemical fertilizers.Their respective average contribution rates were as follows:in shallow groundwater,sewage and manure accounted for 33.6%,followed by soil nitrogen at 33.5%and chemical fertilizers at 21.5%.For middle groundwater,the rates were 43.3%for sewage and manure,34.4%for soil nitrogen,and 18.1%for chemical fertilizers.In deep groundwater,soil nitrogen led with 54.4%,chemical fertilizers followed at 25.1%,and sewage and manure contributed 18.5%.An uncertainty analysis revealed that the contribution rates of chemical fertilizers and soil nitrogen carried significant uncertainty,indicated by their relatively high UI90values.The research results provide a reference for understanding nitrogen transformation and identifying pollution sources in groundwater.

关 键 词：地下水 硝酸盐 硝化作用 氮转换 贝叶斯同位素混合模型 

分 类 号：X523[环境科学与工程—环境工程]