Environmental behaviors of microplastics in surface water of rivers and bays and predictions of future concentrations after the usage of alternatives of plastics

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K11683
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64010:Environmental load and risk assessment-related
• Research Institution: Chiba Institute of Technology
• Principal Investigator: Kameda Yutaka 千葉工業大学, 創造工学部, 准教授 (60397081)
• Co-Investigator(Kenkyū-buntansha): 田代 豊 名桜大学, 国際学部, 教授 (20441959)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: マイクロプラスチック / 微細粒子 / 顕微FTIR / 河川 / 粒度分布 / AIST-SHANEL / 細粒化

Outline of Final Research Achievements

A novel method to measure microplastics greater than 20 micron in aquatic environment was established and their occurrences in surface water of Tsurumi river was investigated. The observed concentrations were several to 10 times higher than previous reports. This may be caused that their median sizes of the size distributions were approximately 50 micron, indicating that previous microplastics data greater than 330 micron was only a small part of all microplastics. The median sizes were correlated significantly to the tensile strengths of their virgin polymer. This is the important evidence that physically strong polymers can not be fragmentated easier than "soft" polymers.
On the other hand, microplastics concentrations were predicted in Tama river and Tsurumi river by using an AIST-SHANEL simulation model.

Free Research Field

環境化学

Academic Significance and Societal Importance of the Research Achievements

環境中の20μm以上のマイクロプラスチックの調査分析方法を確立した。この点は学術的に解明すべき100μm以下のマイクロプラスチックの環境中挙動の解析に大きな貢献を果たすものと期待される。また、環境中マイクロプラスチックの調査は世界的にも技術的に困難であるが、システマティックな本手法により世界的に調査が促進されるものと考えられる。