Poster Presentation SETAC Asia-Pacific Virtual Conference 2022

Global ocean monitoring program for abundance, characteristics and environmental behaviors of microplastics (≧1 μm) in surface water (#109)

Emiko Fujita 1 , Yutaka Kameda 1
  1. Chiba Institute of Technology, Narashino, CHIBA, Japan

Ocean Microplastics (MPs) is one of emerging issues in the world for a novel style of human life including economics. However, we can not discover milestones to their control because of various polymers with different physico-chemical properties, the wide range of their sizes and widespread of global ocean. As these results, the concentration, size distribution and environmental behaviour, especially fragmentation by weathering of global ocean MPs are still not revealed on a global scale. NYK line, one of Japanese shipping companies, and Chiba Institute of Technology have launched a big project to reveal environmental behaviour of ocean MPs greater than 1 μm since 2021. The project is constituted of 5 sections. At first, sampling methods of global ocean MPs by using NYK line operating ships were developed. MPs samples are collected at approximately 100 sites in a year for free. High speed analytical methods to identify and quantify MPs greater than 1 μm were also developed by using Micro- Fourier transform infrared spectrometer and Micro- Raman spectroscopy, as well as a novel software for accurate identification of polymers. Now, global distribution of various polymers of ocean MPs greater than 20μm could be revealed. Remarkably high concentrations of MPs greater than 20 μm were observed at subpolar areas, Kuroshio current, California current and North Pacific ocean. Interestingly, their polymer compositions were different among gyres. Size distributions of 17 polymers were also different. A median size of polyethylene terephthalate MPs was the largest among all polymers, whereas styrene-butadiene rubber, polyvinyl acetate and polyethylene were smallest. It was also revealed that median sizes of polymer distributions were significantly correlated to tensile strengths of each virgin polymer.  These monitoring data including size distributions, and concentrations of 17 polymers in global ocean is very useful to estimate ecological risk assessment of microplastics.