Environmental assessment group, Korea Environment Institute (KEI), Sicheong-daero, Sejong, 30147, Republic of Korea.
Korea Natural Resources and Economic Research Institute (KNERI), 701-2 Office, Gindo Bldg, 44, Mapo-daero, Mapo-gu, Seoul, Republic of Korea.
Environ Geochem Health. 2019 Feb;41(1):469-480. doi: 10.1007/s10653-018-0099-7. Epub 2018 Mar 24.
Colloid mobilization is a significant process governing colloid-associated transport of heavy metals in subsurface environments. It has been studied for the last three decades to understand this process. However, colloid mobilization and heavy metal transport in soil solutions have rarely been studied using soils in South Korea. We investigated the colloid mobilization in a variety of flow rates during sampling soil solutions in sand columns. The colloid concentrations were increased at low flow rates and in saturated regimes. Colloid concentrations increased 1000-fold higher at pH 9.2 than at pH 7.3 in the absence of 10 mM NaCl solution. In addition, those were fourfold higher in the absence than in the presence of the NaCl solution at pH 9.2. It was suggested that the mobility of colloids should be enhanced in porous media under the basic conditions and the low ionic strength. In real field soils, the concentrations of As, Cr, and Pb in soil solutions increased with the increase in colloid concentrations at initial momentarily changed soil water pressure, whereas the concentrations of Cd, Cu, Fe, Ni, Al, and Co lagged behind the colloid release. Therefore, physicochemical changes and heavy metal characteristics have important implications for colloid-facilitated transport during sampling soil solutions.
胶体的迁移是控制重金属在地下环境中与胶体相关迁移的一个重要过程。在过去的三十年中，人们一直在研究这个过程，以了解它。然而，在韩国的土壤中，很少有研究使用土壤溶液中的胶体迁移和重金属迁移。我们研究了在砂柱中采集土壤溶液时，在各种流速下胶体的迁移。胶体浓度在低流速和饱和状态下增加。在没有 10 mM NaCl 溶液的情况下，pH 值为 9.2 时的胶体浓度比 pH 值为 7.3 时高 1000 倍。此外，在 pH 值为 9.2 时，没有 NaCl 溶液的情况下，胶体浓度比有 NaCl 溶液的情况下高 4 倍。这表明胶体在碱性条件下和低离子强度下应在多孔介质中增强其迁移能力。在实际的田间土壤中，胶体浓度的增加会导致土壤溶液中 As、Cr 和 Pb 的浓度增加，而在初始瞬间改变土壤水压力时，Cd、Cu、Fe、Ni、Al 和 Co 的浓度则滞后于胶体的释放。因此，胶体促进的运输过程中，物理化学变化和重金属特性对胶体迁移具有重要意义。
