[O-08] Poster presentations by senior high school students

[O08-P34] The Abundance and Composition of Microplastics in Lake Biwa

*Mayu Kimitsuki¹, Ryusuke Kimitsuki², Michio Kumagai³ (1.Ritsumeikan Moriyama High School, 2.University of Alberta, 3.Ritsumeikan University)

Keywords:Micro Plastics, Lake Biwa, Nile Red

A lot of plastics are flowing out from rivers into the ocean, which is becoming a social problem. Lake Biwa, the largest lake in Japan is no exception. Recently, microplastics were confirmed in Lake Biwa, and we decided to conduct research to better understand the situation. In this study, a total of 25 surveys were conducted from March 2019 to January 2022 to investigate the number, color, and size of plastics. In addition, microplastic components were analyzed using the Nile Red staining method to discern if they are microplastics. As a result, several microplastics were found per ton of lake water. We also discovered that there are larger microplastics (>1 mm) in the North Basin than in the South Basin. We concluded that this may be due to the existence of water circulation of Lake Biwa and the difference in residence time between the North Basin and the South Basin. By investigating the types and proportions of plastics, we decided to find out the characteristics of plastics in Lake Biwa.