Stabilization of Arsenic-Contaminated Agricultural Soil Using Various Amendments.

Arsenic (As) is a ubiquitous trace element in the environment. The mine tailings generated during ore mineral processing have been identified as an anthropogenic source of As. Chemical stabilization of As using soil amendments is considered for remediating As-contaminated soils. The objective of this study was to evaluate the effect of amendments(acid mine drainage treatment sludge (AMDTS), steel making slag (SS), limestone (LS)) on As stabilization and subsequent reduction of As mobilization in amended soils. Soils was collected from agricultural land adjacent to the SD mine and MJ mine in Korea. Each amendment was applied to soils at 1, 3, and 5% w/w ratio. As adsorption by various amendments, Wenzel’s sequential extraction, Onken’s sequential extraction and X-ray diffraction (XRD) analysis of amendments were conducted. As a result, the effectiveness of AMDTS for arsenic removal in aqueous phase was the highest as determined by high Fruendlich adsorption coefficient. Limestone was not able to remove arsenic from the solution. Application of AMDTS 5% significantly decreased amounts of water-soluble & exchangeable As(WE-As)  compared to SS and LS by results of both Wenzel’s and Onken’s extractions. However, Application of LS increased WE-As concentrations because of high pH in amended soil. Applications of AMDTS increased As concentration in the Fe-As fraction from Onken’s extractions. Mineralogical components in AMDTS were found as calcite and goethite in XRD study. Therefore, reduced As mobility in AMDTS treated soil can be attributed to the greater As adsorption by goethite(α-FeOOH). AMDTS is the most effective amendment in this study.