Title
TRANSPORTATION PATHWAYS OF LAND SOURCE BASED MICROPLASTICS INTO THE MARINE ENVIRONMENTS: THE CONTEXT OF RIVERS
Author
A. H. M. ENAMUL KABIR, MASAHIKO SEKINE, TSUYOSHI IMAI, KOICHI YAMAMOTO
Year
2020
Journal
Proceedings of the 22nd IAHR-APD Congress 2020, Sapporo, Japan
Abstract
Marine microplastics pollution has been a global emerging threat. Rivers have been identified as the major
transporting pathways of microplastics from land sources into marine environments. This study investigated
microplastics in the two rivers i.e. Awano River (AR) and Majime River (MR) which are flowing into the Sea
of Japan (SJ) and the Seto Inland Sea (SIS) respectively in the Yamaguchi prefecture, Japan. River surface
water samples were collected from the selected stations (n=12) from the upstream to downstream directions.
Filtration, wet peroxidation, and density separation methods were applied to extract microplastics. Polymers
were identified through ATR-FTIR analysis. The mean microplastics abundance results (AR− 131±17.12 n/L,
MR− 272.5±299.15 n/L) revealed high-level pollution. Characterization demonstrated that small microplastics
(<1 mm) in sizes, fibers and fragments in shapes were predominant characteristics for these rivers. Polymer
identification results revealed that polyethylene, polypropylene, vinylon and polyethylene terephthalate were
the major polymers. Both the point and non-point sources could release MPs. The estimated loadings (AR−
92.36 billion particles per day and MR− 3.48 billion particles per day by numbers) into the SJ and SIS marine
environments represented the fate of large quantities Japan land originated MPs as well as same major
polymer types in these rivers and marine environments indicated that the Japan land contributed to
microplastics pollution largely. Overall, the river freshwater systems were found to be highly MPs polluted
and the prominent MPs transporting pathways from land-sources to the marine environments.
Instrument
FTIR 4600
Keywords
microplastics, marine environment, river, transportation