太湖区小微水体氮素内源释放-沉降动态规律  

Dynamics of endogenous nitrogen release and sedimentation in small water bodies of the Taihu Lake Plain

作　　者：张声权 林涵 朱毅 刘雪梅[1] 夏永秋[2,4] ZHANG Shengquan;LIN Han;ZHU Yi;LIU Xuemei;XIA Yongqiu(College of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China;Institute of Soil Science,Chinese Academy of Sciences,Changshu National Agro-Ecosystem Observation and Research Station,Nanjing 210008,China;College of Agricultural Science and Engineering,Hohai University,Nanjing 211100,China;University of Chinese Academy of Sciences,Nanjing 211135,China)

机构地区：[1]华东交通大学土木建筑学院,南昌330013 [2]中国科学院南京土壤研究所,江苏常熟农田生态系统国家野外观测研究站,南京210008 [3]河海大学农业科学与工程学院,南京211100 [4]中国科学院大学南京学院,南京211135

出　　处：《农业环境科学学报》2024年第8期1859-1868,共10页Journal of Agro-Environment Science

基　　金：国家自然科学基金项目(42177401)。

摘　　要：为探究小微水体氮素内源释放-沉降的动态规律,本研究于2023年1月至11月期间,在太湖平原水网区选取了5个具有代表性的沟、塘、浜等小微水体进行连续监测。每月定期对上覆水体、沉积物以及沉降颗粒物样品进行采集,并同步测定氮浓度及理化因子。基于孔隙水扩散模型,计算了沉积物-水界面NH_(4)^(+)、NO_(3)扩散通量,并同步计算了NH_(4)^(+)、NO_(3)沉降通量和NH_(4)^(+)、NO_(3)内源释放通量。研究结果表明,太湖平原水网区小微水体的氮素内源释放以NH_(4)^(+)为主,NH_(4)^(+)内源释放总量在224~9631 kg·km^(-2)·a^(-1)之间,扩散通量介于50~312 kg·km^(-2)·a^(-1),对水体氮浓度的贡献率为2.2%~15.1%。相较于河流、湖泊等大型水体,小微水体的内源贡献占比相对较低。进一步分析表明,上覆水与沉积物之间的浓度差以及流速等因素,是影响小微水体内源释放的关键。小微水体氮素内源污染较为严重,为有效降低氮素内源污染,应强化沉积物管理,严格把控外源污染物的输入,积极提升水体的自然净化能力,合理调控水体流速,并构建完善的监测与预警体系。To investigate the dynamics of endogenous nitrogen release and sedimentation in small water bodies,we conducted continuous monitoring of five such representative water bodies,including ditches,ponds,and streams,of the Taihu Lake Plain water network area from January to November 2023.Samples of the overlying water,sediment,and settling particulate matter were collected monthly,and the nitrogen concentrations and physicochemical factors were determined synchronously.The diffusion fluxes of NH_(4)^(+) and NO_(3) at the sedimentwater interface,as well as their sedimentation and endogenous release fluxes,were calculated on the basis of the pore water diffusion model.The results indicated that the endogenous nitrogen released in small water bodies of this water network area was predominantly in the form of NH_(4)^(+),with the total amount released ranging from 224 to 9631 kg·km-2·a-1 and the diffusion fluxes ranging from 50 to 312 kg·km-2·a-1,contributing 2.2%to 15.1%to the nitrogen concentration of the water body.Compared with the proportion of endogenous nitrogen contribution from large water bodies,such as rivers and lakes,that from small water bodies was relatively low.Further analysis revealed that the concentration difference between the overlying water and sediment,as well as the flow velocity,were key factors affecting endogenous nitrogen release in small water bodies.Endogenous nitrogen pollution in small water bodies was severe.To effectively reduce such pollution,steps should be taken to strengthen sediment management,strictly control the input of exogenous pollutants,actively enhance the natural purification capacity of water bodies,reasonably regulate the water flow velocity,and establish a complete monitoring and early warning system.

关 键 词：小微水体 内源污染 沉积物-水界面 内源氮释放 

分 类 号：X52[环境科学与工程—环境工程]