River banks and channels as hotspots of soil pollution after large-scale remediation of a river basin

Riparian areas are highly dynamic systems where the control of soil pollution might be particularly challenging. Limited accessibility to river banks and bed sediments makes reclamation operations particularly difficult in these topographical positions, in comparison to floodplains. This usually leads to the large-scale spread of pollutants following pollution episodes in riparian areas. Here, we aimed to evaluate the persistence of trace-element pollution in the soils of Guadiamar River Valley (SW Spain), a large-scale remediation after a mine-spill. We monitored topsoil along the river basin, and in different topographical positions across the river section (river channel, river banks and floodplain), 16 years after a pollution episode and subsequent remediation program. River channels and banks were identified as hotspots of soil pollution, where soluble concentrations of As, Cd and Zn were significantly higher than in floodplains. Along the basin, soil pH and carbonate content was h...河岸带（Riparian Areas）是高度动态的生态系统，土壤污染管控在此类区域往往极具挑战性。相较于泛滥平原（Floodplain），河岸与河床沉积物的可达性极差，使得该地形区位的修复作业尤为困难。这通常会导致污染事件发生后，污染物在河岸带范围内大规模扩散。本研究旨在评估西班牙西南部瓜迪亚马尔河谷土壤中痕量元素污染（Trace-element Pollution）的持久性，该区域曾在矿山溢漏事故后开展过大规模修复工作。本研究于污染事件及后续修复工程实施16年后，对该流域的表层土壤（Topsoil）展开了监测，监测点位涵盖河道（River Channel）、河岸（River Banks）及泛滥平原等河流断面的不同地形区位。研究发现河道与河岸为土壤污染热点区域（Hotspots of Soil Pollution），其中砷（As）、镉（Cd）及锌（Zn）的可溶性浓度显著高于泛滥平原。沿该流域，土壤pH值与碳酸盐含量则h...