International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Bangkok, 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok, 10330, Thailand.
Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand; Center of Excellence in Environmental Innovation and Management of Metals (EnvIMM), Environmental Research Institute, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
Environ Res. 2024 Nov 1;260:119660. doi: 10.1016/j.envres.2024.119660. Epub 2024 Jul 22.
The knowledge about co-transport of goethite and As to investigate the effect of goethite colloids on As transport under various degrees of seawater intrusion, particular extremely conditions, in groundwater environment is still limited. The main objective is to investigate the influence of seawater intrusion on the sorption, migration, and reaction of Asand goethite colloids into sand aquifer media under anoxic conditions by using the bench-scale and reactive geochemical modeling. The research consisted of two parts as follows: 1) column transport experiments consisting of 8 columns, which were packed by using synthesis groundwater at IS of 0.5, 50, 200, and 400 mM referring to the saline of seawater system in the study area, and 2) reactive transport modeling, the mathematical model (HYDRUS-1D) was applied to describe the co-transport of As and goethite. Finally, to explain the interaction of goethite and As, the Derjaguin-Landau-Verwey-Overbeek (DLVO) calculation was considered to support the experimental results and HYDRUS-1D model. The results of column experiments showed goethite colloids can significantly inhibit the mobility of As under high IS conditions (>200 mM). The R of As bound to goethite grows to higher sizes (47.5 and 65.0 μm for 200 and 400 mM, respectively) of goethite colloid, inhibiting As migration through the sand columns. In contrast, based on R value, goethite colloids transport As more rapidly than a solution with a lower IS (0.5 and 50 mM). The knowledge gained from this study would help to better understand the mechanisms of As contamination in urbanized coastal groundwater aquifers and to assess the transport of As in groundwater, which is useful for groundwater management, including the optimum pumping rate and long-term monitoring of groundwater quality.
为了研究在不同程度海水入侵下，特别是在地下水环境极端条件下，针铁矿与砷的共迁移对砷迁移的影响，有关针铁矿胶体对砷在地下水中迁移影响的知识仍然有限。本研究的主要目的是利用柱实验和反应地球化学模型，研究在缺氧条件下，海水入侵对砷和针铁矿胶体在含水层介质中的吸附、迁移和反应的影响。研究包括以下两部分：1）柱传输实验，包括 8 个柱，使用合成地下水，在研究区域海水系统的盐度下，IS 值分别为 0.5、50、200 和 400mM，以及 2）反应传输建模，应用数学模型（HYDRUS-1D）来描述砷和针铁矿的共迁移。最后，为了解释针铁矿和砷的相互作用，考虑了德加古林-兰德沃维尔-奥弗贝克（DLVO）计算，以支持实验结果和 HYDRUS-1D 模型。柱实验的结果表明，在高 IS 条件下（>200mM），针铁矿胶体可以显著抑制砷的迁移性。与砷结合的针铁矿的 R 值增大到更高的尺寸（200mM 和 400mM 时分别为 47.5 和 65.0μm），抑制了砷在砂柱中的迁移。相比之下，基于 R 值，针铁矿胶体比具有较低 IS（0.5 和 50mM）的溶液更快地传输砷。本研究获得的知识将有助于更好地了解城市化沿海地下水含水层中砷污染的机制，并评估地下水砷的迁移，这对于地下水管理，包括最佳抽水率和地下水质量的长期监测，是有用的。
