Test methods for evaluating the influence of redox conditions on leaching of toxic chemicals from geomaterials

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02236
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Osaka University
• Principal Investigator: Inui Toru 大阪大学, 工学研究科, 教授 (90324706)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 地下水汚染 / 溶出 / 吸・脱着 / 酸化還元反応 / 重金属

Outline of Final Research Achievements

Recycled geomaterials, and excavated soils/rocks often contain anthropogenic and geogenic toxic elements, although their concentrations are very low. To promote their sustainable material cycles in construction works, environmental suitability needs to be verified. This research presents the laboratory testing results to evaluate the effects of redox reactions on the leachability and mobility of toxic elements, to predict these effects appropriately by modifying the existing leaching tests as the new testing methods. In addition, to propose cost-effective remedial options against the leaching of heavy metals mobilized by oxidation reactions, long-term performance of the immobilization treatment for the acidic excavated rock was experimentally verified. Also, numerical simulations were conducted to propose appropriate configurations for the embankment structures containing the soils and rocks with geogenic contamination to limit the oxidation due to rainfall infiltration.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

地盤材料には有害物質が様々な形態で存在するため，地中環境に伴う酸化還元条件が溶出挙動に及ぼす影響を考慮して環境安全性の評価を行う必要がある．本研究は，地盤材料の粒径や試験スケールと酸化反応とそれに伴う重金属溶出量との定量関係を明らかにした点，従来評価が困難であった還元反応が有害物質の溶出挙動に及ぼす影響を評価しうる試験法を提案した点に学術的意義があるといえる．さらに，酸化還元反応の影響を適切に評価しうる試験方法の提案，対策方法を提示したことは，微量の有害物質を含有する地盤材料の環境安全性を適切に管理した上で資源としての有効利用に貢献しうる点で社会的意義があると考える．