基于氮氧同位素技术的千岛湖流域典型山区河流硝酸盐来源解析  

Identifying Seasonal Variation of Nitrate Sources in Mountainous Rivers at the Qiandao Lake Basin Based on Nitrogen and Oxygen Isotopes

作　　者：张子宁 许海[2] 江威 詹旭 朱广伟[2] 孙宏伟 邱雨 王圆忆 吴铭杰 刘宇星 李慧赟[2] 朱梦圆[2] 秦伯强[2] 张运林[2] ZHANG Zi-ning;XU Hai;JIANG Wei;ZHAN Xu;ZHU Guang-wei;SUN Hong-wei;QIU Yu;WANG Yuan-yi;WU Ming-jie;LIU Yuxing;LI Hui-yun;ZHU Meng-yuan;QIN Bo-qiang;ZHANG Yun-lin(School of Environment and Ecology,Jiangnan University,Wuxi 214122,China;Key Laboratory of Lake and Basin Water Safety,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China;Hangzhou Bureau of Ecology and Environment Chun'an Branch,Hangzhou 311700,China)

机构地区：[1]江南大学环境与生态学院,无锡214122 [2]中国科学院南京地理与湖泊研究所,湖泊与流域水安全重点实验室,南京210008 [3]杭州市生态环境局淳安分局,杭州311700

出　　处：《环境科学》2025年第4期2232-2241,共10页Environmental Science

基　　金：国家自然科学基金项目(42271126);国家重点研发计划项目(2023YFC3207803);中国科学院南京地理与湖泊研究所自主部署科研项目(NIGLAS2022GS03)。

摘　　要：千岛湖是长三角地区重要的饮用水水源地,其生态环境对周边地区具有重要的战略意义.为了准确识别千岛湖入库的硝酸盐(NO_(3)^(−)-N)污染来源及其空间分布特征,首次开展了千岛湖流域4条典型山区入湖河流流域的水样采集工作,分析不同区域的NO_(3)^(−)-N浓度,并结合δ^(15)N-NO_(3)^(−)和δ^(18)O-NO_(3)^(−)双稳定同位素SIAR模型解析了各水系的NO_(3)^(−)-N来源及其贡献率.结果表明:①各流域氮浓度偏低,ρ[总氮(TN)]均值分布在0.99~4.31 mg·L^(−1)之间,以NO_(3)^(−)-N为主要的氮素来源,4条河流的NO_(3)^(−)-N浓度有明显的季节差异,呈现出春季>冬季>夏季>秋季的趋势,其中春季的ρ(NO_(3)^(−)-N)可达到秋季时期的3.2倍.②各流域的δ^(15)N-NO_(3)^(−)和δ^(18)ONO_(3)^(−)值分别为1.52‰~14.29‰和−2.76‰~10.13‰.③4条河流均呈现出春夏季化肥和土壤氮的贡献率较大,分别约25%~51%和23%~39%,而秋冬季生活污水贡献率较大,约26%~67%.研究显示,千岛湖流域主要的NO_(3)^(−)-N污染源为农业面源污染,不同土地利用类型的NO_(3)^(−)-N污染也具有一定的差异性,流域面积较大的区域在4个季节中NO_(3)^(−)-N污染贡献变化幅度相对稳定,而流域面积较小的区域则有明显波动.研究分析了千岛湖流域的主要NO_(3)^(−)-N来源,为千岛湖流域水质管理和污染源控制提供了依据.Qiandao Lake is an important source of drinking water in the Yangtze River Delta,and its ecological environment is of great strategic significance to the surrounding areas.To identify the sources and spatial distribution characteristics of nitrate(NO_(3)^(−)-N)pollution in the Qiandao Lake,we conducted,for the first time,the collection of water samples from four typical mountainous inlet river basins in the Qiandao Lake Basin,analyzed the concentrations of NO_(3)^(−)-N,and resolved different sources and their contribution in each water system by combining theδ^(15)N-NO_(3)^(−)andδ^(18)O-NO_(3)^(−)dual stable isotope analysis in R(SIAR)model.The results showed that:①Nitrogen concentrations in the different watersheds were relatively low,with mean total nitrogen(TN)levels ranging from 0.99 to 4.31 mg·L^(−1).NO_(3)^(−)-N emerged as the main nitrogen source,and conspicuous disparities were observed in NO_(3)^(−)-N concentrations across the four rivers,consistently demonstrating a pattern of spring>winter>summer>autumn,of which the NO_(3)^(−)-N concentration during spring could be up to 3.2 times of that observed during autumn.②The values ofδ^(15)N-NO_(3)^(−)andδ^(18)O-NO_(3)^(−)in each watershed ranged from 1.52‰to 14.29‰and from−2.76‰to 10.13‰,respectively.③All four rivers showed a greater proportion of fertilizer and soil nitrogen during spring and summer,which accounted for approximately 25%to 51%and 23%to 39%,respectively,and a greater proportion of domestic sewage during autumn and winter,which accounted for approximately 26%to 67%.The study showed that the main source of NO_(3)^(−)-N pollution in the Qiandao Lake Basin was agricultural non-point source pollution,and some variabilities were also observed in NO_(3)^(−)-N pollution in different land-use type areas.NO_(3)^(−)-N pollution contributions remained relatively stable across the larger basin area,while exhibiting significant fluctuations in the smaller basin area.This work analyzed the main sources of NO_(3)^

关 键 词：氮同位素 氧同位素 硝酸盐污染 SIAR模型 季节性变化 贡献率 

分 类 号：X522[环境科学与工程—环境工程]