基于氮氧同位素的深水湖泊硝酸盐来源辨析  

An Analysis of Nitrate Sources in Deep Lake Based on Nitrogen and Oxygen Isotopes

作　　者：吴亚丽 亢晓琪 牛远[1,2,3] 兰伟 余辉 WU Ya-li;KANG Xiao-qi;NIU Yuan;LAN Wei;YU Hui(Chinese Research Academy of Environmental Sciences,Institute of Lake Ecological Environment,Beijing 100012,China;National Engineering Laboratory for Lake Pollution Control and Ecological Restoration,Chinese Research Academy of Environmental Sciences,Institute of Lake Ecological Environment,Beijing 100012,China;Key Laboratory of Lake Pollution Control under National Environmental Protection,Beijing 100012,China;College of Water Conservancy,Shenyang Agricultural University,Shenyang 110866,China)

机构地区：[1]中国环境科学研究院湖泊生态环境研究所,北京100012 [2]湖泊水污染治理与生态修复技术国家工程实验室,北京100012 [3]国家环境保护湖泊污染控制重点实验室,北京100012 [4]沈阳农业大学水利学院,沈阳110866

出　　处：《中国农村水利水电》2022年第4期106-113,共8页China Rural Water and Hydropower

基　　金：国家水体污染控制与治理科技重大专项(No.2018ZX07208-005)。

摘　　要：硝酸盐负荷对水体的影响已成为国内外广泛关注的问题。明确水体硝酸盐负荷的主要来源,是精准制定流域氮污染控源减排策略的基础。该研究以深水湖泊千峡湖为研究对象,通过对湖水水化学特征、硝酸盐氮氧同位素组成及各来源(降水、生活污水、肥料、沉积物及周边土壤)氮氧同位素组成的监测研究,定性分析了千峡湖水体硝酸盐变化趋势及其主要来源。并在此基础上,采用稳定同位素模型MixSIAR定量分析各硝酸盐来源的贡献率。结果表明:(1)千峡湖水体上游硝酸盐主要来自人为活动下有机氮等汇入水体发生的硝化作用过程;(2)湖体硝酸盐来源中流域土壤、生活污水、肥料、沉积物、降水的硝酸盐贡献占比分别为87%±9.7%、9.0%±5.9%、2.5%±1.5%、1.2%±0.8%、0.3%±0.4%。千峡湖湖体氮的迁移转化过程以硝化作用为主,迁移转化过程中受人类活动影响较大,因此,产生的硝酸盐含有较高的氮稳定同位素值。该研究可为深水湖泊氮循环及迁移转化过程提供科学依据。The effect of nitrate loading on water has been a hot issue at home and abroad. Clarifying the main sources of nitrate load in water is the basis for accurately formulating nitrogen pollution control and emission reduction strategies. Taking Qianxia Lake for example,this paper analyzes the variations of nitrate and its main sources qualitatively by monitoring the hydro-chemical characteristics and nitrogen and oxygen isotope composition of nitrate of lakes,with the addition of the nitrogen and oxygen isotope composition of various sources(precipitation,domestic sewage,fertilizer,sediment and surrounding soil)in this study. On this basis,the stable isotope model MixSIAR is used to quantify the different contributions of every nitrate source. The results show that:(1) the downstream of Qianxia Lake is greatly affected by livestock manure or urban domestic water,and its sources of nitrate are mainly from the organic nitrogen affected by human activities with high stable nitrogen isotope flowing to water by nitrification;(2) the nitrate for the lake from surrounding soil,domestic sewage,fertilizer,sediment,and precipitation accounts for 87%±9.7%,9.0%±5.9%,2.5%±1.5%,1.2%±0.8%,0.3%±0.4%,respectively. The transfer and transformation process of nitrate in Qianxia Lake is mainly nitrification under the effect of human activities. Therefore,the nitrate produced contains a higher nitrogen stable isotope value. This study can provide a scientific basis for nitrogen cycle,transfer and transformation in deep lakes.

关 键 词：硝酸盐来源 氮氧同位素 贝叶斯同位素混合模型 千峡湖 

分 类 号：TV11[水利工程—水文学及水资源]