近日，天津大学陈玖斌课题组报道了赤水河单次洪水中金属元素的地球化学行为。相关论文发表在2025年2月10日出版的《地球化学学报》上。

据悉，大部分（高达90%）的河流物质主要是在洪水事件中从大陆运到海洋的。为了更好地控制其全球生物地球化学循环及其对海洋生态系统的影响，对河流系统中元素的地球化学特征及其通量进行表征至关重要。

研究人员报道了赤水河一次自然洪水中，典型金属元素溶解相和悬浮颗粒物的地球化学行为。结果表明，金属元素的地球化学在很大程度上受水动力效应的控制，不同的流量对不同洪水阶段输送的，不同矿物颗粒的形状、大小和密度进行了自然分选。SPM中碱性和碱土金属（Li、Mg、K、Rb和Sr）的最大浓度出现在洪峰前，主要受铝硅酸盐矿物控制。

而过渡金属（Cr、Mn、Fe、Ni和Cu）的丰度峰值滞后于流量峰值，这是由于粗颗粒或重矿物姗姗来迟，矿物物相分析证明了这一点。此外，受pH值影响的可溶性碱/碱土金属颗粒载荷，与溶解载荷之间的分配系数（Kd）较低且稳定，而受SPM含量影响较大的过渡金属颗粒载荷，与溶解载荷之间的分配系数（Kd）较高且波动。

总体而言，本研究揭示了赤水河天然洪水期间，水动力分选对金属元素地球化学的明显影响，在表征河流通量及其对海洋生态系统的影响时应考虑到这一点。

附：英文原文

Title: Geochemical behaviors of metal elements during a single flood event in the natural Chishui River, Southwest China

Author: Liang, Zhongxuan, Wang, Keyi, Cai, Hongming, Wang, Zhongwei, Yuan, Wei, Chen, Jiubin

Issue&Volume: 2025-02-10

Abstract: The majority (up to 90%) of riverine materials is transported from the continent to the ocean mainly in flood events. It is thus crucial to characterize the geochemistry of elements and their flux in river system in order to better constrain their global biogeochemical cycling and impact on the oceanic ecosystem. However, the geochemical behavior including the distribution, migration and partitioning of typical metal elements amongst different phases, during hydrodynamic flood event remains still to be well explored. Here, we investigated the geochemical behaviors of typical metal elements in dissolved phase and suspended particulate matter collected from a single flood event in the natural Chishui River, Southwest China. The results showed clearly that the geochemistry of metal elements was largely controlled by the hydrodynamic effect, of which the different flowrates introduce a natural sorting of different mineral particles transported at different flood stages, depending on their shape, size and density. The maximum concentrations of alkaline and alkaline earth metals (Li, Mg, K, Rb and Sr) in SPM appeared before the flood peak, which was largely controlled by aluminosilicate minerals. However, transition metals (Cr, Mn, Fe, Ni and Cu) showed their abundance peaks lagging behind the flowrate summit, as a result of the late arrival of coarse particles or heavy minerals, evidenced by the mineralogical phase analysis. In addition, the distribution coefficient (Kd) between particulate and dissolved loads were lower and stable for soluble alkali/alkaline earth metals which could be affected by pH, while higher and fluctuant for transition metals that were largely influenced by SPM content. Overall, the present study reveals clear effects of hydrodynamic sorting on the geochemistry of metal elements during the flood event of the natural Chishui River, which should be taken into account when characterizing the riverine flux and their impact on marine ecosystem.

DOI: 10.1007/s11631-025-00762-1

Source: https://link.springer.com/article/10.1007/s11631-025-00762-1