基于多元同位素示踪技术的查干湖无机氮来源解析研究

Inorganic nitrogen is one of the main factors that causes lake eutrophication, and excessive inorganic nitrogen inputs seriously threatens the safety of aquatic ecosystem. For preventing and controlling water eutrophication, identifying the pollution source and estimating the input inorganic nitrogen loads are essentially required. But until now, the studies focused on the sources of inorganic of lakes are still insufficient. As a result, an effective way of controlling inorganic nitrogen pollution in the first place was difficult to apply, not to mention controlling the lake pollution. It is difficult to control inorganic nitrogen pollution from source, which makes the effect of lake pollution control is poor. This project takes Chagan Lake in the Northeast China as a research area. By combining field monitoring, hydro-chemical characteristics, multi-isotopic analysis, laboratory simulation experiment, SIAR and IMB models, we will carry out systematic research on lake water, sediments, precipitation, channel water, groundwater and potential sources of inorganic nitrogen pollution, and focus on the following four research parts..(1) Status of lake water environment and characteristics of inorganic nitrogen pollution;.(2) The sources of inorganic nitrogen in external ways;.(3) The inorganic nitrogen loads of different input ways;.(4) The contribution and influence of different input ways and external pollution sources to on the inorganic nitrogen pollution of Chagan Lake..These research work can provide scientific basis for making source-control strategies on inorganic nitrogen pollution of Chagan Lake, and ensure the health and stability of ecosystem of this lake.

无机氮是导致湖泊富营养化的主要污染物质，过量的无机氮输入严重威胁水生生态系统安全，无机氮来源解析及入湖负荷估算是有效防治水体富营养化的前提和基础。目前，对于湖泊无机氮污染来源的研究比较薄弱，难以从源头上加以控制，使得湖泊污染治理效果较差。本项目以东北地区查干湖为研究区，通过野外监测、水化学测定、多元同位素分析、室内模拟实验、SIAR模型及IMB模型等方法，对查干湖湖水、沉积物、大气降水、入湖渠道水、周边地下水及潜在无机氮污染源开展系统研究，以弄清查干湖水环境现状及无机氮污染特征，解析外源入湖途径水体中无机氮的来源，量化不同输入途径入湖无机氮负荷，阐明不同途径和外源污染源对查干湖水体无机氮的贡献及影响作用，为制定科学可行的查干湖水体无机氮污染源头控制措施提供依据，确保查干湖生态系统健康稳定。

无机氮是影响湖泊水体水质和造成水体富营养化的重要污染指标，识别无机氮的来源并定量估算不同输入途径入湖无机氮负荷具有重要意义，将为湖泊水体污染防治提供科学支撑，助推湖泊富营养化问题的解决。.本项目以查干湖作为研究区，开展了系统的野外监测、采样和室内分析工作，掌握了查干湖水环境现状及无机氮污染特征，在获取了区域典型氮污染源的稳定同位素组成特征的基础上，精确解析了外源入湖途径水体中无机氮的来源及其相对贡献，量化了不同输入途径入湖无机氮负荷。主要得到如下结果和认识：1）查干湖水质总体较差，污染较为严重，水质可达劣V类和轻度富营养状态，受新建灌区退水影响，湖水无机氮浓度呈现出西高东低的空间分布特征；2）渠道水和地下水中硝酸盐来源呈现出明显的季节性变化，在枯水期，粪便和污水是渠道水和地下水中硝酸盐的主要来源，而在丰水期，粪便和污水贡献比例有所下降，化肥和土壤有机氮的贡献有所增加；3）外源输入途径是查干湖无机氮的主要来源，且表现出季节性变化，地下水和大气降水分别是枯水期和丰水期无机氮的主要外源输入途径，同时，沉积物释放对查干湖无机氮的贡献也不容忽视。研究结果可为制定科学可行的查干湖水体无机氮污染源头控制措施提供依据，确保查干湖生态系统健康稳定。