A study on the behavior of toxic elements in aerosols based on XAFS and isotope analyses

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K19953
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: The University of Tokyo
• Principal Investigator: Sun Jing 東京大学, 大学院理学系研究科(理学部), 特任研究員 (40868428)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: XAFS / 有害元素 / カルスト

Outline of Final Research Achievements

In this study, we conducted research to elucidate the speciation of toxic elements released as aerosols and their migration behavior in the environment. As the former, we analyzed the chemical state of radiocesium in silica particles (CsMP) released from the Fukushima Dai-ichi Nuclear Power Plant accident using the X-ray absorption fine structure (XAFS) method with a superconducting transition edge sensor detector (TES: Transition Edge Sensor) that has extremely high energy resolution, and found that radiocesium exists in a dissolved state in glass. The latter study was conducted in a karst plateau in Guizhou Province, China, using sulfur and oxygen isotope ratios of sulfate ions and strontium isotope ratios in combination with concentrations of various elements. As a result, it was revealed that the presence of more than 50% anthropogenic elements in the water samples. We are also planning to conduct further research on heavy metal elements in these samples.

Free Research Field

環境化学

Academic Significance and Societal Importance of the Research Achievements

CsMP中の放射性セシウム（RCs）の化学状態の解明は、沈着後のRCsの挙動を推定する上で極めて重要である。この結果から、シリカ粒子の溶解と共にCsが水に溶出することが示唆され、その風化挙動の理解が今後重要になることが分かった。また本研究から、XAFS法中の微量元素の化学種解明のために超伝導転移端検出器（TES）が有効であることが分かった。またカルスト中の元素の人為起源の割合推定に成功したことは、今後さらにエアロゾルとして沈着した有害重金属元素の起源と環境挙動を解明する上で重要な貢献をすると期待される。