西藏雅鲁藏布江及狮泉河大坝拦截作用对砷迁移转化的影响数据集（2017.8，2018.1和5月）

河流筑坝预计将对物质运移产生重要影响。为研究西藏高原大坝拦截对河流砷迁移转化的影响，以西藏雅鲁藏布江流域和狮泉河流域上的两个水库（藏木水库和狮泉河水库）为研究对象，于2017年8月和2018年1月和2018年5月分别采集狮泉河水库和藏木水库的库区分层水和沉积柱芯样品，以及水库出、入库河流水体的数据。藏木水库和狮泉水库入库河流水体中溶解态As含量的季节变化受低As径流和高As热泉输入的混合调节。水力停留时间(WRT)是调节库区和出库水体中溶解态As含量随时间变化的关键因素，在丰水期，沉积物-水界面表面氧化层的缺失减少了砷在表面沉积物中的积累。两个水库沉积物中砷的迁移主要受锰氧化物和有机质控制。水力停留时间长的水库更有利于As的滞留，沉淀作用是As滞留的主要机制。狮泉河水库水力滞留时间长（385 天），能够有效拦截上游55%的总砷输入；而藏木水库由于水力滞留时间很短（1.1 天），对砷没有明显的拦截作用。这些因素对下游河流流域的地球化学和生态环境具有重要意义。River damming is expected to exert significant impacts on material transport. To investigate the effects of dam impoundment on arsenic migration and transformation in rivers on the Tibetan Plateau, two reservoirs located in the Yarlung Zangbo River Basin and the Shiquan River Basin, namely the Zangmu Reservoir and the Shiquanhe Reservoir, were selected as the study subjects. Water samples with layered profiles and sediment core samples from the reservoir zones, as well as water quality data of inflowing and outflowing rivers of the two reservoirs, were collected in August 2017, January 2018 and May 2018. The seasonal variations of dissolved arsenic (As) concentrations in the inflowing rivers of Zangmu and Shiquanhe Reservoirs are modulated by the mixing of low-As runoff and high-As hot spring inputs. Hydraulic residence time (WRT) is a key factor regulating the temporal changes of dissolved As concentrations in reservoir and outflow waters. During the wet season, the absence of surface oxidation layers at the sediment-water interface reduces the accumulation of arsenic in surface sediments. Arsenic migration in the sediments of the two reservoirs is mainly controlled by manganese oxides and organic matter. Reservoirs with longer hydraulic residence times are more conducive to As retention, with sedimentation being the primary mechanism for As retention. The Shiquanhe Reservoir has a long hydraulic residence time (385 days), effectively intercepting 55% of the total As input from the upstream; whereas the Zangmu Reservoir, with a very short hydraulic residence time (1.1 days), shows no significant As interception capacity. These factors hold important implications for the geochemistry and ecological environment of downstream river basins.

搜集汇总

背景与挑战

背景概述

该数据集聚焦于西藏高原雅鲁藏布江和狮泉河流域的大坝拦截作用对砷迁移转化的影响，基于2017-2018年对藏木水库和狮泉河水库的分层水、沉积柱芯及河流水体的采样数据。研究发现，水力停留时间是调控水库砷含量的关键因素，狮泉河水库因水力停留时间长能有效拦截上游55%的砷输入，而藏木水库则无显著拦截作用，揭示了沉积物-水界面过程及锰氧化物、有机质对砷迁移的控制机制。数据通过标准方法验证，具有较高可信度，对理解河流地球化学和生态环境有重要意义。