Are organic compounds adsorbed on microplastics stable? -Potential for photodegradation-

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K17905
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 64010:Environmental load and risk assessment-related
• Research Institution: University of Shizuoka (2022-2023); Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture (2021)
• Principal Investigator: Noro Kazushi 静岡県立大学, 食品栄養科学部, 助教 (80827642)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: マイクロプラスチック / 多環芳香族炭化水素 / 光分解

Outline of Final Research Achievements

Photodegradation of plastic produces microplastics (MPs) in marine environments. Plastics can adsorb polycyclic aromatic hydrocarbons (PAHs) and can be transported overlong distances. However, the impact of adsorbed pollutants on the photodegradation remains unknown. Here, we show that adsorbed PAHs act as photocatalysts that promote the photodegradation of polyethylene. Upon lightirradiation, coloration and surface degradation of the PAH-adsorbed polyethylene sheets were observed, indicating that the PAH-adsorbed polyethylene sheets are less resistant to light. Furthermore, spme PAHs adsorbed on polyethylene MP exhibited lower photodegradation rates than the aqueous phase. These results indicate that PAHs can act as photocatalysts; their role of PAHs may have two adverse effects on marine environment. First, enhanced photodegradation of plastic waste increased the production of MPs. Second, the lifetime of PAHs is extended, thereby enhancing PAHs pollution in marine environments.

Free Research Field

環境化学

Academic Significance and Societal Importance of the Research Achievements

本研究は、多環芳香族炭化水素類(PAHs)がマイクロプラスチック(MPs)の生成を促進していることを示した。これまで、毒性の高いPAHsのみの排出が規制されてきたが、MPs汚染を抑制するためにはMPs生成促進能の高いPAHsを規制する必要があるだろう。