Microplastic Analysis in the Arctic Reveals Sources of Influx

Recently, a team of researchers investigated the extent of plastic pollution in the western Arctic Ocean. This study, which was published in the journal Chemosphere, quantitatively assesses the microplastic contamination in the water column of the western Arctic Ocean (1). The findings from this study reveal that the Arctic Ocean, considered one of the last frontiers on Earth, is not immune to the plastic pollution problem impacting the rest of the planet.

What did the research team do in their study?

The research team collected 324 replicate water samples across depths ranging from 9 to 297 meters using a Conductivity, Temperature, and Depth (CTD) rosette sampler. These 324 samples came from the Bering Strait, which is the gateway between the Pacific and Arctic Oceans, through the Chukchi Sea and into the southern reaches of the Beaufort Sea (1). This sample area was selected so that the researchers can see the plastic pollution issue in several marine environments, including the Chukchi, Alaskan, and Mackenzie shelves, as well as the marginal ice zones of the Canadian Basin (1).

The landscape of the Arctic ocean with melting glaciers and pieces of ice. Generated with AI. | Image Credit: © Pihta - stock.adobe.com

The study’s findings underscore the significance of the plastic pollution issue. Out of all the sampling stations, 94.4% of them revealed to have at least a small microplastic presence, with average concentrations of 0.06 particles per liter (equivalent to 60 particles per cubic meter) across the water column (1). The highest recorded concentration was at the Beaufort Seas station, where researchers encountered 0.22 particles per liter (1). The majority of particles were blue, fibrous, and small, with sizes under 500 micrometers.

The researchers used micro-Fourier transform infrared (μ-FT-IR) spectroscopy to determine that polyolefins, a class of polymers commonly used in packaging and fishing gear, were the most abundant in the samples (1). Because the Arctic Ocean does see some fishing activity, this finding aligns with the anthropogenic activities that do occur in this area.

Where were the microplastics located?

The study found that 59% of MPs were concentrated in the Polar Mixed Layer, the near-surface layer influenced by seasonal melting and freezing (1). Meanwhile, another 22% were located in the Pacific or Atlantic halocline, which is a saltier, denser layer beneath the surface, and 19% were found in the Intermediate Layer of Atlantic Water (1).

In total, 99 particles were confirmed to be composed of specific polymers or monomers (1). The researchers were also able to identify seven additives. Importantly, none of the blank control samples contained microplastics, confirming that contamination did not occur during sample handling.

What is the driver of plastic contamination?

Based on the results of the study, the researchers concluded that long-range oceanic transport, unsurprisingly, was the likely primary driver of contamination. Plastics entering the Pacific Ocean from Asia and North America can travel vast distances via currents such as the Bering Strait inflow, eventually depositing particles in Arctic waters (1). Additionally, local activities, including shipping, fishing, and oil exploration, probably contribute to the problem (1).

The presence of microplastics in Arctic sub-surface waters raises concerns about potential impacts on fragile polar ecosystems (2). Microscopic particles can be ingested by plankton, fish, and other marine organisms, introducing pollutants into the Arctic food web and potentially affecting Indigenous communities that rely on these resources for subsistence (1,2).

What are the key takeaways from this study?

By using FT-IR spectroscopy, the research team was able to learn the extent of the plastic pollution problem in the Arctic Ocean. Although the Arctic Ocean is far north and sees very little human presence, it still sees microplastic contamination in its ocean waters. This suggests two things: that human activity, even if it’s not concentrated in the Arctic Ocean, can still impact the ocean there, and that the pollution issue in the Arctic Ocean is more concerning than initially thought.

Although policies banning single-use plastics and improving waste management are gaining traction, the persistence of plastics in the marine environment means that even distant ecosystems like the Arctic will continue to face threats for decades without significant intervention (1). By mapping the occurrence and movement of microplastics in Arctic waters, this study provides a critical baseline for future monitoring and policymaking as researchers continue to better understand the biological impacts of these pollutants.

References

1. Sambandam, M.; Mishra, P.; Ikenoue, T.; et al. Microplastic Contamination in the Western Arctic Water Column: A Transition from Pristine to Polluted. Chemosphere 2025, 385, 144577. DOI: 10.1016/j.chemosphere.2025.144577
2. Bergmann, M.; Collard, F.; Fabres, J.; et al. Plastic Pollution in the Arctic. Nat. Rev. Earth Environ. 2022, 3, 323–337. DOI: 10.1038/s43017-022-00279-8