异龙湖区浅层地下水NO_(3)^(-)-N浓度时空变化及其来源解析  

Spatiotemporal Variations of NO_3~--N Concentration in Shallow Groundwater around Yilong Lake and Its Source Analysis

作　　者：蒋存征 陈安强[2] 胡万里[2] 付斌[2] 朱林立 刘云娥 黎明琦 王炽[2] 张丹[1] JIANG Cunzheng;CHEN Anqiang;HU WANli;FU Bin;ZHU Linli;LIU Yune;LI Mingqi;WANG Chi;ZHANG Dan(College of Resources and Environment,Yunnan agricultural University,Kunming 650201,P.R.China;Agricultural Environment Resources Institute,Yunnan Academy of Agricultural Sciences,Kunming 650201,P.R.China;Yuxi City Farmland Construction and Soil Fertilizer Workstation,Yuxi 653100,P.R.China;Agricultural and Rural Comprehensive Service Center,Longjie Street,Chengjiang City,Yuxi 653100,P.R.China)

机构地区：[1]云南农业大学资源与环境学院,云南昆明650201 [2]云南省农业科学院农业环境资源研究所,云南昆明650201 [3]玉溪市农田建设与土壤肥料工作站,云南玉溪653100 [4]澄江市龙街街道农业农村综合服务中心,云南玉溪653100

出　　处：《生态环境学报》2025年第4期570-580,共11页Ecology and Environmental Sciences

基　　金：云南省兴滇英才项目(202305AS350013);云南省重大科技专项(202402AE090024)。

摘　　要：明确异龙湖区浅层地下水中NO_(3)^(-)的主要来源、转化过程及主要驱动因素,对防治地下水氮污染和合理利用水资源具有重要意义。于2020年雨季(8月)和2021年旱季(5月)选择异龙湖区农田灌溉井(13个)和居民区生活用水井(10个),共采集46个地下水样品。运用水化学和氮氧同位素(δ^(15)N-NO_(3)^(-)、δ^(18)O-NO_(3)^(-))技术并结合同位素混合模型(SIAR),明确地下水中NO_(3)^(-)的时空分布、转化过程、来源及不同来源氮对地下水NO_(3)^(-)的贡献。结果表明,地下水中氮浓度和形态均受土地利用和雨旱季变化的影响,农田地下水中氮浓度高于民用地,旱季高于雨季。农用地25%的采样点地下水ρ(NO_(3)^(-)-N)超过地下水III类水质要求(GB/T 14848—2017)规定的20 mg·L^(-1)。水土环境对农用地浅层地下水氮浓度影响较大,反映和影响地下水氮浓度的关键性因子是水中的EC、pH、DO和温度(t),而土壤碳氮指标对地下水氮浓度影响较弱。硝化作用是异龙湖区地下水中主要的氮转化过程,地下水NO_(3)^(-)主要来源于粪污氮、土壤有机氮、化肥氮,其对民用地和农用地的贡献率分别为46.02%、25.83%、21.49%和35.27%、34.39%、24.57%。因此,改善污水收集处理设施、合理堆置和施用粪肥、控制土壤氮淋失是防治异龙湖区地下水中NO_(3)^(-)污染的重要策略。Groundwater has become an important water source for production and daily life because of its wide distribution,stable volume,and good quality.However,due to the increasing intensity of intensive agricultural planting,acceleration of urbanization,and inadequate collection and treatment facilities for domestic sewage,various nitrogen pollutants have directly or indirectly entered groundwater,resulting in severe nitrate (NO_(3)^(-)) pollution.This not only exacerbated the regional water supply crisis,but also posed a threat to human health.The significant spatiotemporal differences in the nitrogen concentration of groundwater were driven by seasonal precipitation or irrigation,land use,nitrogen fertilizer input,and soil type,which increased the complexity of NO_(3)^(-) sources in the groundwater.The main sources of NO_(3)^(-) in groundwater are the atmospheric deposition of nitrogen,soil organic nitrogen,animal manure,domestic sewage nitrogen,chemical fertilizer nitrogen,and industrial wastewater nitrogen.It is influenced by microbial-driven nitrogen cycling processes such as nitrification and denitrification.Therefore,accurately identifying the source of NO_(3)^(-) in groundwater and analyzing its contribution rate is of great significance for controlling groundwater NO_(3)^(-)pollution.On the basis of qualitatively identifying the sources of NO_(3)^(-) in groundwater using methods such as hydrochemistry and isotope tracing,the introduction of the stable isotope source analysis model (SIAR) not only improved the accuracy of source analysis,but also made it more convenient to quantify multiple NO_(3)^(-) sources.Yilong Lake is one of the nine major plateau lakes in the Yunnan Province.Farmlands,towns,or villages around the lake area are cross-distributed,with a high degree of agricultural intensification,a large vegetable planting area,a high crop replanting index,and high water,fertilizer,and pesticide input intensities.In addition,the lake area is mainly composed of river alluvial deposits or lake sediments with

关 键 词：浅层地下水 硝酸盐来源 同位素 时空变化 

分 类 号：X523[环境科学与工程—环境工程]