State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
Sci Total Environ. 2021 Aug 15;782:146780. doi: 10.1016/j.scitotenv.2021.146780. Epub 2021 Mar 27.
Based on 197 monthly river water and groundwater samples and 30 event-scale precipitation samples, our study reports the distribution of hydrogen and oxygen isotopes and pollution indicators in Min River Basin. The variation of δO and d-excess indicate that the water source in the upper main course water is more variable and that in the middle-lower part is relatively stable. Comparison between plots of δH versus δO in the river water and precipitation reflect the dominant water source is different between river water in the upper and middle-lower parts. The electrical conductivity (EC) shows a similar spatial variation trend for main course water collected in four campaigns. The pollutant concentration change at the confluences of main tributaries shows that the inflow of Heishui River and Dadu River leads to decreased NO and Cl, while that of Xi River, Pu River and Fuhe River leads to a leap in NO and Cl. A significant positive correlation is observed between EC and δO, indicating the consistent control of water sources on isotope distribution and water quality. The relationship between elevation and δO in the main course river water suggests that the factors affecting isotope distribution vary spatially. "Altitude effect" can only be observed in October and November for the upper steepest plateau zone due to the spatial variation in the precipitation stored during the wet season. The "inverse altitude effect" is observed for the upper part during the wet season and for the middle-lower part during the whole study period, which can be explained by the contribution of tributaries with different discharge regimes. Our findings show that water source with different discharge regimes can serve as the leading factor controlling the stream component in multi-tributary river basins with large spatial span and may mask the influence of spatial distribution of precipitation.
基于 197 个月度河流水和地下水样本以及 30 个事件尺度降水样本，本研究报告了闽江流域氢氧同位素和污染指标的分布。δO 和 d-excess 的变化表明，上游干流的水源变化较大，中下游的水源相对稳定。河流水和降水中 δH 与 δO 的关系图表明，上、中、下游河水的主要水源不同。电导率 (EC) 在四次采集的干流水样中表现出相似的空间变化趋势。主要支流汇合处的污染物浓度变化表明，黑水河和大渡河的汇入导致 NO 和 Cl 减少，而西溪、普渡河和富河的汇入导致 NO 和 Cl 跃升。EC 与 δO 之间存在显著的正相关关系，表明水源对同位素分布和水质的控制是一致的。干流河水海拔与 δO 的关系表明，影响同位素分布的因素在空间上存在差异。由于雨季储存的降水在空间上的变化，“海拔效应”仅在上游最陡峭的高原区的 10 月和 11 月观察到。雨季上游和整个研究期间中下游观察到“逆海拔效应”，这可以用不同流量模式的支流的贡献来解释。我们的研究结果表明，具有不同流量模式的水源可以作为控制多支流流域河流成分的主导因素，这可能掩盖了降水空间分布的影响。
