Marine microplastics in the surface waters of "pristine" Kuroshio

Highlights: • First study on microplastics (MPs) in the Kuroshio off eastern Taiwan. • The higher MP levels were found at near river outlets and area with complex current. • Microplastics in the Kuroshio are transported by local currents. • The majority of MPs consisted of PP, PE, PET, and PS. Microplastics (MPs) are ubiquitous in oceans. Their transboundary transport and fate have aroused global attention. Taiwan is located close to the western boundary current-Kuroshio, is an excellent location to study of MP mobility in the global current and Pacific Garbage Patch. This study is the first investigation to understand the microplastic contamination from Taiwan to the Kuroshio. MP concentrations in the area varied from N.D. to 0.15 items m⁻³, with an average concentration of 0.05 ± 0.03 items m⁻³. The majority of MPs were polypropylene, polyethylene, polyethylene and terephthalate. We found two MP hotspots near the coastal zone. One additional hotspot was also identified in the "pristine" Kuroshio suggesting rivers and local currents may play critical roles in transporting or injecting MPs from Taiwan into the North Pacific Gyre. These findings suggest that marine environments are altered by anthropogenic disposal and provide needed data for modelling and prediction of MPs.