研究报告
真翎,吴贤忠,李家兵,谢蓉蓉.闽江感潮河段夏秋季涨落潮河水稳定同位素（N/D/O-18）组成特征解析[J].环境科学学报,2022,42(5):314-324
闽江感潮河段夏秋季涨落潮河水稳定同位素（N/D/O-18）组成特征解析
- Component analysis of N/D/O-18 stable isotope during ebb and flood tides in summer and autumn in the tidal reach of the Minjiang River
- 基金项目：国家自然科学基金（No.42007343）；福建省自然科学基金（No.2021J01195）；福州市科技计划项目（No.2019-S-67）
- 作者
- 单位
- 真翎
- 福建师范大学环境科学与工程学院，福州 350007
- 吴贤忠
- 福州市环境科学研究院，福州 350013
- 李家兵
- 福建师范大学环境科学与工程学院，福州 350007;福建师范大学福建省污染控制与资源循环利用重点实验室，福州 350007;数字福建环境监测物联网实验室，福州 350007
- 谢蓉蓉
- 福建师范大学环境科学与工程学院，福州 350007;福建师范大学福建省污染控制与资源循环利用重点实验室，福州 350007;数字福建环境监测物联网实验室，福州 350007
- 摘要：流域氮污染的稳定同位素表征和溯源对于保障流域污染防控和用水安全具有重要意义，本文通过对感潮河段夏、秋季涨落潮主要断面硝态氮（NO3-）及稳定同位素（δ15N-NO3-、δ18O-NO3-、δD-H2O和δ18O-H2O）组成特征测定及沿线小流域的氮污染入河量测算，探讨了陆域氮排放和水体交换对感潮河段稳定同位素的影响.研究表明：①落潮、涨潮期NO3-均为“秋季＞夏季”，δ15N-NO3-夏、秋两季组成特征基本相近.落潮期δ18O-NO3-为“夏季>秋季”，涨潮期则相反.同季节的NO3-及其同位素总体呈“涨潮期>落潮期”.②落潮期δD-H2O、δ18O-H2O为“夏季>秋季”；涨潮期δD-H2O总体为“夏季>秋季”，δ18O-H2O季节差异较小.夏秋两季δD-H2O在S4~S6断面为“涨潮期<落潮期”，S7~S8为“涨潮期>落潮期”，S9断面夏季为“落潮期＞涨潮期”，秋季则相反.δ18O-H2O在S4~S7断面的涨落潮差异较小，S8~S9为“涨潮期>落潮期”.③小流域氮污染入河量测算与同位素溯源均表明粪污及生活污水源为流域主要污染源，陆域氮排放贡献率最高的河段δ15N-NO3-上升，δ18O-NO3-下降，此外降水蒸发、河流的分流汇合及涨潮影响下的水体交换也一定程度影响研究河段同位素的组成特征.本研究为自然水体的同位素研究及污染溯源提供了重要的技术支撑.
- Abstract：The stable isotope and characteristics traceability of nitrogen pollution through watersheds are of great significance for regional pollution control and water safety. In this study， we measured the nitrate and its N/D/O-18 stable isotopes at multiple key cross-sections of an ebb-flood tidal reach in summer and autumn， and calculated the total nitrogen discharge into the tidal reach， to reveal the effects of terrestrial nitrogen inputs and water exchange to the composition of stable isotopes. Results suggested nitrate concentration in autumn was higher than in summer during both ebb and flood tides periods. The content of δ15N-NO3- did not show much difference between summer and autumn. Differently， the content of δ18O-NO3- in summer was higher in ebb tides， but lower in flood tides compared to those measured in autumn. Meanwhile， both δD-H2O and δ18O-H2O contents in summer were higher in summer during ebb tides， while in flood tides， δD-H2O content was noted higher in summer， and δ18O-H2O content exhibited little seasonal differences. The δD-H2O content during flood tides was lower than that during ebb tides at S4~S6， but higher at S7~S8. The δD-H2O contents at S9 demonstrated the opposite seasonal trends. No significant differences of δ18O-H2O contents between the ebb and flood tides were observed at S4~S7. At S8~S9， the δ18O-H2O content in flood tides was much higher. Finally， both nitrogen discharge for small watersheds and the isotopic traceability indicated that the fecal and domestic sewage sources were the dominant pollution sources in the study area. Besides， the contents of δ15N-NO3- increases and δ18O-NO3-decreases at the reach with the highest terrestrial nitrogen input. Water exchange altered by the rainfall， evaporation， diversions and confluences of rivers and the flood-tide events would affect the isotopic component characteristics to some extent. This study provided important technical support for isotope studies and pollution traceability in natural water bodies.
摘要点击次数： 184 全文下载次数： 302
