武汉蔡甸区浅层地下水氮污染来源识别及其迁移转化过程解析  

Sources,transport and transformation of nitrogen pollution in shalllow groundwater in Caidian District,Wuhan,China

作　　者：曹益 李逸凡 周传富 李朋 李俊霞 CAO Yi;LI Yifan;ZHOU Chuanfu;LI Peng;LI Junxia(School of Environment Studies,China University of Geosciences(Wuhan),Wuhan 430078,China;Hubei Geological Survey,Wuhan 430034,China)

机构地区：[1]中国地质大学(武汉)环境学院,武汉430078 [2]湖北省地质调查院,武汉430034

出　　处：《地质科技通报》2025年第1期262-273,共12页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(42177067)。

摘　　要：近年来,随着人类活动的不断加剧,地下水氮污染成为全球范围内典型的环境问题。为识别浅层地下水氮污染源、贡献比例以及迁移转化特征,采集了湖北省武汉市蔡甸区主要供水区地表水样14个、浅层地下水样24个及土样7个,并测试分析了其水化学指标、氮同位素、氢氧同位素等。基于当地土地利用类型,综合水化学及δ^(15)N-NO_(3)^(-)、δ^(18)O-NO_(3)^(-)双同位素示踪技术,判别了研究区地下水硝酸盐氮污染源及迁移转化规律,同时进一步运用Iso-Source模型定量识别了不同氮污染源的贡献比例。区域氮污染类型以硝酸盐氮为主,其中约66.7%地下水采样点NO_(3)^(-)浓度超出世界卫生组织(WHO)规定限值(10 mg/L),污水和粪便、土壤有机质以及氨肥硝化为主要NO_(3)^(-)来源,其对浅层地下水硝酸盐氮的贡献率均值.分别为48.6%、32.9%、18.5%,受较为明显的人类活动影响;进一步结合区域水化学及氢氧同位素组成显示,区域地表水及地下水氮的形态转化主要受到硝化作用影响与控制。研究结果将为进一步了解蔡甸区氮循环过程及氮污染治理提供理论基础。[Objective]In recent years,increasing human activities have exacerbated groundwater nitrogen pollution,which has become a typical environmental problem globally.To identify nitrogen pollution sources,contribution ratios,transport and transformation characteristics in shallow groundwater,fourteen surface water samples,four shallow groundwater samples,and seven soil samples were collected from the main water supply area of Caidian District,Wuhan City,Hubei Province.These samples were analyzed for water chemical indices,nitrogen isotopes,hydrogen and oxygen isotopes.[Methods]Integrating the local land use type,water chemistry,andδ^(15)N-NO_(3)^(-) and δ^(18)O-NO_(3)^(-) double isotope tracer technology,we identified sources of nitrate nitrogen pollution and determine their transport and transformation patterns.The IsoSource model was further applied to quantitatively.assess the contributions of different nitrogen pollution sources.[Results]The predominant form of nitrogen pollution was nitrate nitrogen,with approximately 66.7%of the groundwater sampling points exceeded the WHO limit(10 mg/L)in NO_(3)^(-) concentration.The primary sources of NO_(3)^(-) were identified as nitrification of sewage and manure,soil organic matter,and ammonia-containing fertilizers,with average contribution rates to shallow groundwater of 48.6%,32.9%,and 18.5%,respectively.These sources were found to be significantly affected by human activities.Further analysis integrating regional water chemistry and hydrogen-oxygen isotopic compositions revealed that the morphological transformation of nitrogen in regional surface and groundwater nitrogen was predominantly controlled by nitrification processes.[Conclusion]The findings of this research provide a theoretical framework for better understanding the nitrogen cycling process and implementing effective nitrogen pollution control measures in Caidian District.

关 键 词：氮污染 硝酸盐氮 Iso-Source模型 双同位素示踪技术 浅层地下水 武汉 

分 类 号：X523[环境科学与工程—环境工程]