title: Importance of chemical binding type between As and iron-oxide on bioaccessibility in soil: Test with synthesized two line ferrihydrite.
abstract: 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.
authors.affiliation: Seoul Center, Korea Basic Science Institute, 6-7, Inchon-ro 22-gil, Seongbuk-gu, Seoul 02855, Republic of Korea.
authors.forename: Seulki
authors.initials: S
authors.lastname: Jeong
authors.affiliation: Division of Public Infrastructure Assessment, Environmental Assessment Group, Korea Environmental Institute, Sejong 30147, Republic of Korea.
authors.forename: Kyung
authors.initials: K
authors.lastname: Yang
authors.affiliation: Department of Environmental Science, Hankuk University of Foreign Studies, 81 Oedae-ro, Mohyeonmyeon, Cheoin-gu, Yongin-si, Gyeonggi-do 17035, Republic of Korea.
authors.forename: Eun Hea
authors.initials: EH
authors.lastname: Jho
authors.affiliation: Department of Civil and Environmental Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, Republic of Korea. Electronic address: kpnam@snu.ac.kr.
authors.forename: Kyoungphile
authors.initials: K
authors.lastname: Nam
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D001682:Biological Availability; D005290:Ferric Compounds / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D012989:Soil Pollutants; C092844:ferric oxyhydroxide; D001151:Arsenic
keywords: Arsenic; Binding type; Bioaccessibility; Ferrihydrite; XPS analysis