Abstract:

Large amounts of toxic metals are discharged into rivers and lakes, but little is known about the factors that drive the adsorption and transformation of these metals in the hyporheic zone and the exchange flux across the sediment-water interface. To better understand transport and transformation of metal ions in the hyporheic zone, flume experiments and numerical simulations were performed in a streambed with periodic bedforms using zinc ions. Compared to non-adsorbing contaminant, the results show that adsorption leads to a more rapid decrease in the concentration of Zn 2 + in the overlying water, and a lower final concentration is reached. The mass of adsorbed ions is several times higher than that of free ions in the bedform’s water phase. Indeed, metal adsorption is in the shallow layer of the streambed. Although this prevents heavy metal groundwater contamination, the same cannot be said of shallow layer of the hyporheic zone. Knowledge of the migration and transformation of metal ions in the hyporheic zone provides insights pertinent to the restoration of polluted rivers.

摘要:

大量的有毒金属被排放到河流和湖泊中，但对这些金属在潜流带的吸附和转化以及沉积物-水界面交换通量的驱动因素知之甚少。为了更好地了解金属离子在潜流带中的迁移和转化，采用水槽实验和数值模拟的方法对具有周期性河床形态的锌离子进行了研究。结果表明，与非吸附污染物相比，吸附使上覆水体中zn2 +浓度下降更快，最终浓度更低。河床中吸附离子的质量是游离离子质量的几倍。事实上，金属吸附在河床的浅层。虽然这样可以防止地下水重金属污染，但地下水潜流带的浅层就不能这样说了。了解金属离子在潜流带中的迁移和转化为污染河流的修复提供了相关的见解。

（DOI: 10.1016/j.advwatres.2020.103775, SCI, IF=4.016,3区）