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Microplastics in sea ice drifted to the Shiretoko Peninsula, the southern end of the Sea of Okhotsk

Scientific Reports 2024 2 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Hiroshi Ohno, Yoshinori Iizuka

Summary

Sea ice collected near Japan's Shiretoko Peninsula contained up to 60 microplastic particles per liter, predominantly small fragments under 120 micrometers, confirming that drifting sea ice acts as a carrier and temporary reservoir for microplastics across ocean regions. The findings add to evidence that polar and sub-polar ice systems play an active role in redistributing plastic pollution far from its original sources.

Study Type Environmental

Sea ice is regarded as a temporal sink and carrier of microplastics (MPs). Nevertheless, knowledge and understanding of MPs in sea ice remain sparse. This study investigated the abundance, composition, size (> 30 μm), and shape of MPs in four sea-ice cores retrieved at the southern end of the Sea of Okhotsk. Nine microplastic (MP) types, mostly with fragmentary shapes, were detected among ice-core sections. Most fragmentary MPs were smaller than 120 μm, but all fiber MPs were in the largest size class (> 210 μm). MP concentrations were 0-60 particles/L, with an average of 21 particles/L. Higher occurrences of MPs observed in the lower ice layers are attributable to heavier MP contamination in the southern part of the sea and/or relocation of MPs in the ice matrix. No significant correlation was found between the distributions of MP and inorganic particle (sediment) abundances, implying difference in their kinetics of suspension freezing. Taken together, these findings suggest important implications for elucidating the nature and distribution of MPs in sea ice.

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