中文关键词硝酸盐污染氮氧同位素基于R语言的稳定同位素模型(SIAR)通扬运河源解析 英文关键词nitrate pollutionnitrogen and oxygen isotopesstable isotope analysis in R (SIAR)Tongyang Canalsource analysis

作者	单位	E-mail
邢子康	河海大学水文水资源与水利工程科学国家重点实验室, 南京 210098 河海大学全球变化与水循环国际合作联合实验室, 南京 210098 长江保护与绿色发展研究院, 南京 210098	xzk@hhu.edu.cn
余钟波	河海大学水文水资源与水利工程科学国家重点实验室, 南京 210098 河海大学全球变化与水循环国际合作联合实验室, 南京 210098 长江保护与绿色发展研究院, 南京 210098
衣鹏	河海大学水文水资源与水利工程科学国家重点实验室, 南京 210098 河海大学全球变化与水循环国际合作联合实验室, 南京 210098 长江保护与绿色发展研究院, 南京 210098	pengyi1915@163.com
钱睿智	江苏省水文水资源勘测局扬州分局, 扬州 225000
王嘉毅	河海大学水利水电学院, 南京 210098

中文摘要 随着城市化的进程和人类活动强度的增加，过高的硝酸盐污染负荷对地表水水质安全构成极大威胁.当前针对地表水体的硝酸盐源解析仅强调了来源的季节性变化特征，而鲜见考虑降雨事件对区域污染源组成的影响.本文以扬州市江都区通扬运河为研究对象，利用氮氧同位素技术和基于R语言的稳定同位素模型（stable isotope analysis in R）定量评价了各类型污染源在不同降雨条件下对水体硝酸盐污染的贡献.结果表明：①通扬运河各区段污染物浓度具有很强的空间变异性.ρ（NO₃^-）和ρ（NH₄⁺）具有相似的空间分布特征，表现为：中游区 > 下游区 > 上游区，中游区较高的城市化水平带来的人类活动加剧了氮污染的输入.②降雨增加了各河段污染物浓度的不确定性，降雨带来的冲刷和稀释效应总体上增加了水体中的ρ（NO₃^-）、ρ（NH₄⁺）、ρ（Cl^-）和ρ（SO₄^2-）.③在无雨和低降雨的条件下，通扬运河水体NO₃^-主要来源于大气沉降（贡献率为27%~47%）和土壤有机氮（贡献率为21%~29%）；在降雨事件影响下，化肥（贡献率为16%~34%）成为了最主要的污染源.降雨造成的污染源变化具有空间差异性，下游区（农业区）化肥和土壤有机氮贡献率的增加较中上游区更加明显.④下游区存在较强的反硝化作用，且低降雨条件下更容易发生硝化和反硝化. 英文摘要 Due to the process of urbanization and the increase in human activities, high nitrate pollution poses a great threat to the surface water quality. Recent analyses of nitrate sources have only emphasized the seasonal variation of the source, rarely considering the impact of precipitation events on the composition of pollution sources. This study selected the Tongyang Canal in Jiangdu District, Yangzhou City, as the research object. Nitrogen and oxygen isotope technology and the stable isotope analysis in R (SIAR) model were used to calculate the contributions of different nitrate sources under different precipitation conditions. The results showed that:① The concentration of pollutants in each section of the Tongyang Canal had strong spatial variability. The concentration of NO^-₃ and NH₄⁺ had a similar spatial distribution (middle > downstream > upstream). The high level of urbanization in the middle reach increased the input of nitrogen. ② Precipitation increased the uncertainty of the concentration in various sections, and the erosion and dilution effects brought via precipitation generally increased ρ(NO₃^-), ρ(NH₄⁺), ρ(Cl^-), and ρ(SO₄^2-). ③ Under the conditions of no and low rainfall, the NO₃^- of the Tongyang Canal mainly came from atmospheric deposition (contribution rate of 27% to 47%) and soil organic nitrogen (contribution rate of 21% to 29%). Influenced by rainfall events, chemical fertilizers (with a contribution rate of 16% to 34%) became the most important source. The changes in pollution sources caused by rainfall were spatially different. The contribution rate of chemical fertilizers and soil organic nitrogen in the downstream reach (agricultural area) increased more significantly than that in the upper and middle reach. ④ There was strong denitrification in the downstream area, and nitrification and denitrification were more likely to occur under low rainfall conditions.

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