Development of a heavy metal leaching assessment model based on liquid-solid ratios

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04601
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: University of Miyazaki
• Principal Investigator: Kenichi Ito 宮崎大学, 国際連携センター, 准教授 (90524695)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 自然由来重金属 / ひ素 / 溶出試験 / 溶出量 / 液固比 / 促進酸化試験

Outline of Final Research Achievements

The batch test with differing liquid-solid ratios was applied to several soils, and it was suggested that heavy metal leaching from sedimentary rocks can be modeled by Henry's adsorption isotherm. For acid sulfate soils, which change with oxidation, it was proposed that the use of accelerated alteration methods to create altered soils for the evaluation by the batch test. As an accelerated alteration test, a new accelerated oxidation test method, in which the soil is heated and humidified, and suppresses physical effects such as slaking was devised. As a result, the new accelerated oxidation method was estimated to be about 16.7 times faster alteration in the 60°C and humidified treatment than in the outdoor exposure test.
The fruits of this study provided a new approach, which is "the batch test with differing liquid-solid ratios with new accelerated oxidation test", for predicting the long-term leaching behavior of soil.

Free Research Field

環境地盤工学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果である簡易な液固比バッチ試験及び促進酸化試験との併用による重金属等の溶出パラメータ取得の試験手法は、自然由来重金属含有土壌及び経時変化で酸性化を伴う酸性硫酸塩土壌について、これまで屋外曝露試験やカラム試験による事象観察でしか把握できなかった重金属等の長期溶出挙動を予測するアプローチ手法である。この成果は広く土壌を扱う分野において土壌中の微量元素の放出挙動の評価手法の発展に貢献するものである。また、このアプローチ手法は汚染土壌の評価を発展させ、汚染土壌対策実務の安全性向上、合理化等に寄与する有益な知見を与えるものである。