15:30 〜 17:00
[MIS17-P11] Distribution of microplastics in shallow sediments in Tokyo Bay
Plastics are ubiquitously used in our life. However, those discarded inappropriately are weathered into microplastics (MPs), generally with a diameter of <5 mm, transported, and accumulated in marine environments. That may damage the shallow marine ecosystems through the seawater to sediment. In this study, we report the distribution of MPs in surface sediments from Tokyo Bay to assess their potential source and behavior near the human environment.
Shallow sediments were collected from 25 stations in Tokyo Bay. MPs were then extracted from shallow samples, and their polymer type, shape, and amount were measured. MPs were often found in sediments 5 – 6 km away from the estuaries. Their particle sizes were larger than the host sediments, suggesting that the MPs are transported farther than general sediment particles.
At eastern stations (inner bay), microplastics were not observed or <5 particles/kg-sediment. At central to western stations, offshore of large and urbanized river, the concentrations were dozens particles/kg-sediment. In addition, only polystyrene particles were found in offshore of the Boso peninsula, on the other hand, several types of polymers were found in northwestern stations. This may indicate the input process of MPs into the bay.
Only two patterns were found for the shape of MPs; fiber and granular. Although the fiber MPs were found at 11 stations , granular samples were found only at 4 stations. This suggests that the shape of MPs may constraint the biophilic behavior during the transportation and sedimentation. The distribution of MPs is potentially controlled by the sedimentological and biological processes in marine system.
Shallow sediments were collected from 25 stations in Tokyo Bay. MPs were then extracted from shallow samples, and their polymer type, shape, and amount were measured. MPs were often found in sediments 5 – 6 km away from the estuaries. Their particle sizes were larger than the host sediments, suggesting that the MPs are transported farther than general sediment particles.
At eastern stations (inner bay), microplastics were not observed or <5 particles/kg-sediment. At central to western stations, offshore of large and urbanized river, the concentrations were dozens particles/kg-sediment. In addition, only polystyrene particles were found in offshore of the Boso peninsula, on the other hand, several types of polymers were found in northwestern stations. This may indicate the input process of MPs into the bay.
Only two patterns were found for the shape of MPs; fiber and granular. Although the fiber MPs were found at 11 stations , granular samples were found only at 4 stations. This suggests that the shape of MPs may constraint the biophilic behavior during the transportation and sedimentation. The distribution of MPs is potentially controlled by the sedimentological and biological processes in marine system.