Perfluoroalkyl Compounds on the Microplastics Found in Sagami Bay and Effect of the Inflow Rivers

Microplastics (MP) can cause damage to ocean ecosystem. The environmental problems due to MP contamination is attracting worldwide attention. In this study, the survey was conducted to clarify the origin of MP obtained on various beaches of Sagami Bay from the viewpoint of chemical adsorption. There was no clear difference in the amount of Perfluorinated Compounds (PFCs) adsorbed on various MP materials. PS foam with a large surface area adsorbed more PFCs per unit weight than resin. The amount of PFOS adsorbed on the MP collected on Kugenuma beach downstream Hikiji river, where PFOS concentration in the water sample was relatively high, was higher than that adsorbed on the MP collected from the other two beaches. The total rainfall for one month before sampling in autumn was higher than the annual average, and the amount of PFCs adsorbed on the MP in autumn was lower than that in other seasons. The amount of PFOS adsorbed on the MP was high in the river downstream from the middle of the Hikiji River. Partition coefficient (Kd) of PFOS that obtained from the elution test used the collected MP was higher than the valve by adsorption test for unused MP. Apparent Kd of PFOS by the MP on Kugenuma beach and the river water at Hujimi bridge of Hikiji river was the same order as the valve that obtained from the elution test used the collected MP. It has been clarified that the MP fragments flowed into the Hikiji river were adsorbed with PFOS and flowed down, and they were drifted to the Kugenuma beach.