Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

A (Atmospheric and Hydrospheric Sciences ) » A-OS Ocean Sciences & Ocean Environment

[A-OS13] Ocean circulation and material cycle in coastal seas

Mon. May 27, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Kiyoshi Tanaka(University of Tokyo), Akihiko Morimoto(Ehime University), Yuichi Hayami(Saga University), Kazuhiko Ichimi(Seto Inland Sea Regional Research Center, Kagawa University)

[AOS13-P01] An experimental study on degradation and fragmentation of marine plastic debris


Keywords:microplastics, rubbish, ultraviolet ray

Marine contamination due to plastic debris,especially microplastics, is attracting worldwide attention at the present time. It has already been reported that microplastics are present over the world's ocean, but the process of their formation has not been clarified in detail.In this study, we aim to elucidate the process in which plastics drifting on the surface of the sea are degraded by ultraviolet rays and fragmentized by physical processes such as waves. We attempt to reproduce the regradation and fragmentationan processes in a laboratory experiment. First, an ultraviolet irradiation experiment was conducted. The ratio of the ultraviolet intensity between a high-pressure UV lamp irradiated and sunlight was measured under the sunny, cloudy, and rainy conditions.Thereafter, plastic (polyethylene without additives) pieces of the same size were irradiated with ultraviolet rays under a high-pressure UV lamp. The degraded plastic pieces were entered into a plastic tube wite seawater and sand, which was rotated to represented motion by waves in shorelines to fragmentize. The change of fragmentation rate of the plastic pieces will be examined by varying the irradiation time and the rotating times, respectively.