Scientific studies are still evaluating how plastics from the oceans get back to us and onto our plates or rather stomachs and what consequences this has.
We know for certain that even smallest ocean dwellers ingest microplastics. These animals like plankton are eaten by larger animals next up in the food chain and the microplastics are also „eaten“. This way, microplastics reach animals higher up the food chain hierarchy like polar bears. Humans who eat marine animals can thus also eat plastic. Micro plastics have been found in the stomachs of various fishes, so called filtering animals (like mussels) also take in microplastics. They filter the salt water and live on the suspended particles or microorganisms in it. Exact quantities of microplastics could be defined in mussels which had been cultivated in aqua culture in the ocean: Lisbeth van Cauwenberghe and Colin R. Janssen described in their study from 2014 „Microplastics in shellfish cultured for human consumption“, that, depending on the amount of mussels consumed (average quantities for „high to low“ eaters of mussels based on the EFSA Food Consumption Database 2011) it is possible to intake 1800 to 11.000 microplastic particles a year. 1)
Microplastic has the attribute to collect and bond toxics on its surface, so these find their way into the metabolism of the animals or even humans. The consequences of this have not yet been studied conclusively. However it is feared that these toxics have negative implications for animals and humans and thus form a further source of environmental pollutants or harmful chemical substances.
A topical study on fish by Rochman et al. 2013 shows that technical plastics, which have already absorbed POPs e.g. pesticides like DDT or polychlorinated biphenyls (PCB) within the marine environment („persistent organic pollutants“ are hazardous organic materials which are hardy biodegradable) have led to hepatic stress among fish. 2) 3)
1)Lisbeth van Cauwenberghe, Colin R. Janssen, Microplastics in bivalves cultured for human consumption, Environmental Pollution, Volume 193, October 2014, Pages 65-70, ISSN 0269-7491, http://dx.doi.org/10.1016/j.envpol.2014.06.010.
2) Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress Chelsea M. Rochman, Eunha Hoh, Tomofumi Kurobe & Swee J. Teh Scientific Reports 3, doi:10.1038/srep03263
3) Plastic as a carrier of POPs to aquatic organisms: A model analysis.
Albert Aart Koelmans, Ellen Besseling, Anna Wegner, and edwin M. Foekema Environ. Sci. Technol., Just Accepted Manuscript DOI: 10.1021/es401169n
Publication Date (Web): June 11, 2013