基于水化学与氮氧同位素的喀斯特山区水体硝酸盐来源示踪与估算——以平寨水库为例  

Tracing and estimation of nitrate sources based on hydrochemistry and nitrogen and oxygen isotopes in karst mountainous water:A case study of the Pingzhai reservoir

作　　者：王艳碧 周忠发[1,2] 孔杰 王翠 邹艳 张富强 李梨 WANG Yan-bi;ZHOU Zhong-fa;KONG Jie;WANG Cui;ZOU Yan;ZHANG Fu-qiang;LI Li(College of Geography And Environmental Sciences/Karst Research Institute,Guizhou Normal University,Guiyang 550001,China;The State Key Laboratory Incubation Base for Karst Mountain Ecology Environment of Guizhou Province,Guiyang 550001,China)

机构地区：[1]贵州师范大学地理与环境科学学院/喀斯特研究院,贵州贵阳550001 [2]贵州省喀斯特山地生态环境国家重点实验室培育基地,贵州贵阳550001

出　　处：《中国环境科学》2023年第10期5365-5376,共12页China Environmental Science

基　　金：国家自然科学地区基金项目(4216148);贵州省科技计划(黔科合基础[2020]1Y154)。

摘　　要：平寨水库地处喀斯特山区,是贵州省重要的灌溉和饮用水库之一,其水环境质量深刻影响着居民生产生活.以平寨水库为研究对象,采用水化学分析方法、氮氧双同位素技术结合稳定同位素混合模型(Bayesian mixing model,MixSIAR),定量识别研究区水体硝酸盐各污染源的贡献率.结果表明:河流及库区水体溶解无机氮主要以硝态氮形态存在,时间上表现为平水期>丰水期>枯水期,空间上呈现出各河流上游浓度差异较大,下游与库区浓度接近,坝前丰水期的硝酸盐浓度较高的特征;研究区水体硝酸盐的转化主要以硝化作用为主,枯水期和平水期其主要来源是生活污水与牲畜粪便和土壤有机氮,丰水期主要为化学肥料;各时期硝酸盐来源中,整体表现为库区的生活污水与牲畜粪便的贡献率高于河流,土壤有机氮与化学肥料的贡献率低于河流.从生活污水与牲畜粪便贡献率来看,其值在河流、库区枯水期分别为59.3%、70.8%,在河流、库区平水期分别为58.3%、72.6%,丰水期值较小.从土壤有机氮贡献率和化学肥料贡献率来看,丰水期贡献率均高于枯水期和平水期.河流、库区丰水期源自土壤有机氮的贡献率分别为35.1%、32.8%,源自化学肥料的贡献率分别为36.4%、30.7%.平寨水库水环境质量保护应重点加强各城镇与农村居民生活污水排放的管控,纳雍河流域要减少生活污水的排放,提高污水集中处理能力.此外,环境保护还要提升各流域农业活动污染的防治,合理处置各流域散户养殖畜禽粪便的排泄和堆放,避免污染物进入水体造成污染,为居民饮用水安全与生态保护提供保障.Pingzhai reservoir is located in the karst mountainous area.It is one of the important irrigation and drinking water reservoirs in Guizhou province,the water environment quality has a profound impact on the production and life of residents.Taking Pingzhai reservoir as the research object,this essay adopted hydrochemical analysis method,nitrogen and oxygen dual isotope technology combined with MixSIAR model to quantitatively identify the contribution rate of each pollution sources of nitrate in the water body of the study area.The results showed that:(1)Dissolved inorganic nitrogen in rivers and reservoir water bodies mainly exists in the form of nitrate nitrogen,which is manifested in time as flat season>wet season>dry season.In space,there is a significant difference in concentration in the upstream of each river,while the concentration in the downstream is close to that in the reservoir area.The nitrate concentration in the wet season before the dam is relatively high.(2)The conversion of nitrate in the water body of the research area is mainly through nitrification.The main sources are domestic sewage,livestock manure,and soil organic nitrogen during the dry and flat seasons,while chemical fertilizers are the mail sources during the wet season.(3)In terms of nitrate sources,the contribution rates of domestic sewage and livestock manure in the reservoir area were higher than that of rivers,and the contribution rates of soil organic nitrogen and chemical fertilizer were lower than that of rivers.In terms of contribution rates of domestic sewage and livestock manure,the numbers are 59.3%and 70.8%in the dry season of rivers and reservoirs respectively,and 58.3%and 72.6%respectively during the normal water period of rivers and reservoirs.And the number is quite small during wet season.From the perspective of soil organic nitrogen contribution rate and chemical fertilizer contribution rate,the contribution rate during the wet season is higher than that during the dry and flat season.The contribution rates of soil or

关 键 词：喀斯特山区 硝酸盐来源 水化学特征 氮氧同位素 MixSIAR模型 平寨水库 

分 类 号：X142[环境科学与工程—环境科学]