2022 Fiscal Year Final Research Report
Transition in mechanisms of toxic metal(loid) leaching with alteration of physicochemical surface structure of excavated rock
| Project/Area Number |
20K12211
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 64010:Environmental load and risk assessment-related
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| Research Institution | Meiji University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
肴倉 宏史 国立研究開発法人国立環境研究所, 資源循環・廃棄物研究センター, 室長 (70331973)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 掘削岩 / 大気曝露 / 乾湿繰返し / 還元 / 表面変質 / 黄鉄鉱 / 炭酸化 / 重金属等 |
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| Outline of Final Research Achievements |
Appropriate evaluation of the amount of arsenic leached from excavated rock after reuse is necessary for the suitable reuse of the large amount of excavated rock generated by tunnel construction. This study aims to quantitatively clarify the relationship between the amount of change in arsenic phases associated with surface structural alteration and the drying-wetting cycles and reduction conditions of the excavated rock exposed after reuse. Under wetting-drying cycles, toxic metal(loid)s were released from pyrite with the oxidation of pyrite caused by fine granulation. The main factors that change the release of toxic metal(loid)s from pyrite would be the decrease in pH and the formation of amorphous and crystalline iron derived from the pyrite oxidation. Chemical and biological reduction increased the amount of As released, but the amount of increase was less than that under the drying-wetting cycles.
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| Free Research Field |
土壌学
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| Academic Significance and Societal Importance of the Research Achievements |
建設工事で大量に発生する掘削岩は，処分場の残余容量が少ないため，環境に悪影響を与えないように再利用することが期待されている．本研究成果は，掘削岩を再利用する際に還元環境よりも乾湿を繰り返す大気暴露条件のほうが掘削岩からの重金属類の溶脱が高まる可能性を定量的に明らかにしたものである．
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