Development and assessment of new risk assessment methods
Title of Research:XXXXDevelopment of a conceptual model for environmental risk assessment ofmicroplastics and a trial risk assessment in Tokyo Bay
Principal Investigator:
Wataru Naito. National Institute of Advanced Industrial Science and Technology (AIST), ResearchInstitute of Science for Safety and Sustainability (RISS), Group Leader
w-naito@aist.go.jp
Collaborators:
Masashi Gamo, AIST, RISS
Kiyotaka Tsunemi, AIST, RISS
Hideo Kajihara, AIST, RISS
Kyoko Ono, AIST, RISS
Isamu Ogura, AIST, RISS
Bin-Le Lin, AIST, RISS
Xue Mianqiang, AIST, RISS
Hiroyuki Mano, AIST, RISS
Yuichi Iwasaki, AIST, RISS
Naohide Shinohara, AIST, RISS
Yuriko Ishikawa, AIST, RISS
Summary of Research:
The purpose of this study project is to review the existing domestic and international literature forenvironmental risk assessment of microplastics (MPs), to develop a conceptual model that concretely
shows the risk assessment procedure of MPs, and to conduct a trial risk assessment for Tokyo Bay. In
FY2021, a literature review was conducted to highlight the latest trends and parameters for emission
estimation, exposure analysis, hazard assessment and risk assessment of MP. In order to conduct atrial risk assessment for Tokyo Bay, we attempted to estimate emissions from major sources, evaluate
key parameters in exposure concentration analysis, gather and compile a dataset for thedevelopment of species susceptibility distributions (SSD), and calculate effect concentrations basedon SSD. In addition, an online survey was conducted to investigate public perceptions of marine
plastic litter and MP. In the next fiscal year, while verifying the methods and data that contribute to
the environmental risk assessment of MPs studied in the current fiscal year, we will present a
conceptual model (framework and approach) for environmental risk assessment and managementthat takes into account the characteristics of MPs by illustrating a trial risk assessment for Tokyo Bay.
Furthermore, based on recent trends, we will update research issues and points in MP risk
assessment and management, which are necessary for more realistic risk assessment.
Timeline:
March 2020Topics:
JCIA-LRI Annual Workshop “Development of a conceptual model for environmental risk assessment of
microplastics and a trial risk assessment in Tokyo Bay”, August 2021 (Online)
Publications:
1. Iwasaki Y., Mano H., Lin BL, Naito W. “Current status and issues of hazard assessments focusing

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Development and assessment of new risk assessment methods
on the effects of microplastic particles on aquatic organisms” Jpn. J. Environ. Toxicol. 24: 53-61,2021.
Takeshita KM., Iwasaki Y, Sinclair TM, Hayashi TI, Naito W “Developing a species sensitivity
distribution for nano- and microplastic particles by using Bayesian hierarchical modeling”
SETAC NA 42nd Annual Meeting、Oral Presentation, Nov. 2021 (Virtual Meeting)Takeshita KM., Iwasaki Y, Sinclair TM, Hayashi TI, Naito W“Illustrating a Species Sensitivity
Distribution for Nano- and Microplastic Particles Using Bayesian Hierarchical Modeling” Env. Tox.
Chem. doi:10.1002/etc.5295, 2022
Ono K, Xue M, Naito W, Tsunemi K. “Preliminary source analysis of microplastics entering TokyoBay”, 56th Annual Meeting of Japanese Society of Water Environment, Poster Presentation,
March 2022, (Univ. Toyama, On-line)