Plastics at sea

Reports of pollution by discarded plastic products crowd the pages of the popular press reporting on the environment. I’ve blogged on plastics before; see https://blogs.nicholas.duke.edu/citizenscientist/microplastics/. This is an update on a rapidly expanding scientific literature. The Web-of-Science lists 69 papers on plastic pollution that have been published just since the start of this year (2730 total).

Much of the plastic that pollutes the oceans arrives in rivers. A recent study found that there was about 1 item of litter for each square meter of riverbank along 250 sites in Germany. Cigarette butts and plastic dominated these collections. Most items were linked to recreational users. The world’s largest river, the Amazon, long used for trash disposal, had fragmented plastics in a quarter of the fishes examined, with polyethylene, polyvinyl chloride, and polypropylene dominating the sources. The same varieties of plastic dominate pieces retrieved from the northwest Pacific Ocean. Plastic items dominate the beach litter on Svalbard, an Arctic island chain at 80o N, where they are carried north by the Gulf Stream. And on Cobscook Bay in eastern Maine, plastics from the fishing industry—nylon rope and oil bottles—dominate the catch. Plastic pollution is a worldwide phenomenon.

No one wants plastic in their food, but as plastics are fragmented, they are ingested by both freshwater and marine fishes and show up in the products we catch for human consumption. What is not good for us, is not good for the fishes and birds that eat those fishes. In Svalbard, 87% of the Northern Fulmars, a predatory seabird, had plastic in their intestinal tract. At least one study reports increased mortality from plastics in birds and marine turtles that feed on fish from the sea.

Some plastics are more susceptible that others to fragmentation and decomposition, largely by sunlight. And, there are some promising reports of new plastics that decompose naturally in the environment and of organisms that can degrade them. But, overall the blame for plastic pollution rests on you and me.

It is best to avoid one-use plastics, in bags and packages. And plastic items should never be cast willy-nilly to the environment. Rather, more thoughtful disposal will include recycling and collection of trash destined for incineration, where at least the energy content o f the plastic can be put to good use. Landfills are a less desirable option, but better than no collection at all.

References

Andrade, M.C. and 6 others. 2019. First account of plastic pollution impacting freshwater fishes in the Amazon: Ingestion of plastic debris by piranhas and other serrasalmids with diverse feeding habits. Environmental Pollution 244: 766-773.

Duncan, E.M. and 12 others. 2019. Microplastic ingestion ubiquitous in marine turtles. Global Change Biology 25: 744-752.

Jaskolski, M.W. and 4 others. 2018. Trash on Arctic beach: Coastal pollution along Calypsostranda, Bellsund, Svalbard. Polish Polar Research 39: 211-224. DOI: 10.24425/118746

Kiesseling, T. and 5 others. 2019. Plastic pirates sample litter at rivers in Germany—Riverside litter and litter sources estimated by schoolchildren. Environmental Pollution 245: 545-557.

Luo, W. and 5 others. 2019. Comparison of microplastic pollution in different water bodies from urban creeks to coastal waters. Environmental Pollution 246: 174-182.

Pan, Z., and 9 others. 2019. Microplastics in the northwestern Pacific: Abundance, distribution, and characteristics. Science of the Total Environment 650: 1913-1922.

Trevail, A.M., G.W. Gabrielsen, S. Kuhn and J.A. Van Franeker. 2015. Elevated levels of ingested plastic in a high Arctic seabird, the northern fulmar (Fulmarus glacialis). Polar Biology 38: 975-981.

Windsor, F.M. and 6 others. 2019. A catchment-scale perspective of plastic pollution. Global Change Biology doi: 10.1111/gcb.14572

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