Study on the mechanism of the heavy metal immobilization effect of organic soil amendments in soils

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05835
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 41030:Rural environmental engineering and planning-related
• Research Institution: Osaka Metropolitan University (2022-2023); Osaka Prefecture University (2021)
• Principal Investigator: Sakurai Shinji 大阪公立大学, 大学院農学研究科, 講師 (30531032)
• Co-Investigator(Kenkyū-buntansha): 中桐 貴生 大阪公立大学, 大学院農学研究科, 准教授 (80301430)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 重金属 / 不動化 / 有機質資材 / 化学形態 / pH / 酸化還元電位 / 吸着

Outline of Final Research Achievements

As an alternative to conventional remediation techniques for heavy metal-contaminated soil, organic soil amendments (materials) to inhibit the transfer of heavy metals into crops have attracted attention. The factor behind the heavy metal immobilization effect of materials is not clear. In this study, we aimed to clarify the relative magnitude of the transfer inhibition effect of each factor, mainly in terms of three factors: pH, oxidation-reduction potential (ORP), and such adsorption to organic matter. The results suggested that immobilization due to adsorption to organic matter is superior to insolubilization due to ORP and that soil pH is involved in the immobilization effect by applying materials and maintaining chemical forms. Furthermore, it was suggested that about cadmium, cadmium ions are mainly transformed into various chemical forms in the soil.

Free Research Field

農業農村工学

Academic Significance and Societal Importance of the Research Achievements

有機質資材を投与し重金属を不動化させることは，重金属汚染農地での安全な農作物生産において，フードセキュリティを担保する点から重要である．結果的に，不動化に関連すると考えられる各要因に関する寄与度の序列をある程度明らかを見出すことができ，不動化に向けた資材の選定に有用な知見が得られた．また，カドミウムでは土壌中に存在する化学種の同定ができ，土壌汚染の事例によっては効率的な農作物抑制が見込まれる．しかしながら土壌管理によっては有機物を投入することで重金属が可溶化する場合や，不溶化要因の各種寄与度の定量までには至らず更なる検討が必要である．