title: Potential for leaching of arsenic from excavated rock after different drying treatments.
abstract: Leaching of arsenic (As) from excavated rock subjected to different drying methods is compared using sequential leaching tests and rapid small-scale column tests combined with a sequential extraction procedure. Although the total As content in the rock was low (8.81 mg kg(-1)), its resulting concentration in the leachate when leached at a liquid-to-solid ratio of 10 L kg(-1) exceeded the environmental standard (10 μg L(-1)). As existed mainly in dissolved forms in the leachates. All of the drying procedures applied in this study increased the leaching of As, with freeze-drying leading to the largest increase. Water extraction of As using the two tests showed different leaching behaviors as a function of the liquid-to-solid ratio, and achieved average extractions of up to 35.7% and 25.8% total As, respectively. Dissolution of As from the mineral surfaces and subsequent re-adsorption controlled the short-term release of As; dissolution of Fe, Al, and dissolved organic carbon played important roles in long-term As leaching. Results of the sequential extraction procedure showed that use of 0.05 M (NH4)2SO4 underestimates the readily soluble As. Long-term water extraction removed almost all of the non-specifically sorbed As and most of the specifically sorbed As. The concept of pollution potential indices, which are easily determined by the sequential leaching test, is proposed in this study and is considered for possible use in assessing efficacy of treatment of excavated rocks.
authors.affiliation: Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
authors.forename: Jining
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Kosugi
authors.affiliation: Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Riya
authors.affiliation: Department of Bioapplications and Systems Engineering (BASE), Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
authors.forename: Yohey
authors.initials: Y
authors.lastname: Hashimoto
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Dayangfang 8, Beijing 100012, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Hou
authors.affiliation: Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Terada
authors.affiliation: Department of Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan. Electronic address: hosomimasaaki1130@gmail.com.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hosomi
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000032:analysis*; D003890:Desiccation; D004787:Environmental Pollution / Q000032:analysis*; D008903:Minerals / Q000032:analysis* / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
chemical_list: D008903:Minerals; D012987:Soil; D012989:Soil Pollutants; D001151:Arsenic
keywords: Arsenic; Drying; Excavated rock; Leaching