Seoul Center, Korea Basic Science Institute, 6-7, Inchon-ro 22-gil, Seongbuk-gu, Seoul 02855, Republic of Korea.
Division of Public Infrastructure Assessment, Environmental Assessment Group, Korea Environmental Institute, Sejong 30147, Republic of Korea.
J Hazard Mater. 2017 May 15;330:157-164. doi: 10.1016/j.jhazmat.2017.02.009. Epub 2017 Feb 7.
Bioaccessible concentrations of As associated with Fe oxide as different chemical binding types were determined in soils using the in vitro Physiologically Based Extraction Test (PBET). When compared to the five-step sequential extraction data, most of the As extracted by in vitro PBET originated from the amorphous Fe oxide-bound fraction, and more importantly, the bioaccessibility of As ranged from 0 to 58.8% in 24 soil samples. Two batches of ferrihydrite were synthesized separately. For one batch, As was adsorbed onto the ferrihydrite after synthesis; for the other one, As was added while synthesizing ferrihydrite to co-precipitate. The bioaccessible concentration of As determined by in vitro PBET of the former was 415mg of As/kg of ferrihydrite and that of the latter was 67mg of As/kg of ferrihydrite. X-ray photoelectron spectra (XPS) analysis indicated that As-O-Fe bonds were evident in As-associated ferrihydrite sample and especially, As was found within the Fe oxide lattice in the co-precipitated sample. Our data suggest that binding type between As and Fe oxide should be considered when determining the bioaccessibility of As in soil, which, in turn, greatly influences the realistic risk of As present in soil.
使用体外生理相关提取测试（PBET）在土壤中确定与不同化学结合类型的铁氧化物结合的砷的生物可及浓度。与五步连续提取数据相比，体外 PBET 提取的大部分砷来自无定形铁氧化物结合部分，更重要的是，24 个土壤样品中砷的生物可利用度范围为 0 至 58.8%。分别合成了两批水铁矿。对于一批，砷在合成后吸附在水铁矿上；对于另一批，在合成水铁矿时添加砷以共沉淀。通过体外 PBET 测定的前者的砷生物可利用浓度为 415mg/kg 水铁矿，后者的砷生物可利用浓度为 67mg/kg 水铁矿。X 射线光电子能谱（XPS）分析表明，在与砷结合的水铁矿样品中存在砷-O-Fe 键，特别是在共沉淀样品中发现砷存在于铁氧化物晶格中。我们的数据表明，在确定土壤中砷的生物可利用性时，应考虑砷与铁氧化物之间的结合类型，这反过来又极大地影响了土壤中存在的砷的实际风险。
