Popular Seafood Contaminated with Microplastics, Australian Study Finds

by Vins

Researchers at the University of Exeter and the University of Queensland’s QUEX Institute have found microplastics in crabs, oysters, prawns, squid, and sardines sold as seafood in Australian markets, according to a report published in the scholarly journal Environmental Science & Technology and covered by Medical News Today in August 2020. As Robby Berman reported for MNT, the new findings suggest that microplastics—small pieces of plastic, less than 5mm (about the size of a sesame seed) that are a consequence of plastic pollution—have “invaded the food chain to a greater extent than previously documented.”

The team found plastic from packaging, synthetic materials, or marine debris in all 45 of the seafood samples it studied. The study’s lead author, Francisca Ribeiro, said that, for an average serving, a seafood eater could be exposed to “approximately 0.7 milligrams (mg) of plastic” when ingesting oysters or squid, and “up to 30 mg of plastic” when eating sardines. For comparison, a grain of rice weighs approximately 30mg.

None of seafoods sampled are subject to recall, however.

As MNT reported, approximately 17% of the protein that humans consume worldwide is seafood. Thus the findings suggest that “people who regularly eat seafood are also regularly eating plastic.” According to Tamara Galloway, a researcher from Exeter University who is one of the study’s co-authors, “We do not fully understand the risks to human health of ingesting plastic, but this new method will make it easier for us to find out.”

In October 2020, the Guardian reported that at least 14 million tons of microplastics are likely sitting on the ocean floor—”more than 30 times as much plastic at the bottom of the world’s ocean than there is floating at the surface,” according to an estimate based on new research, Graham Readfearn reported.

As the Guardian report noted, “Stemming the tide of plastic entering the world’s waterways and ocean has emerged as a major international challenge.” In September 2020, leaders from more than seventy countries signed a voluntary pledge to reverse biodiversity loss which included a goal to stop plastic entering the ocean by 2050. The United States, Brazil, China, Russia, India and Australia did not sign that pledge.


Robby Berman, “Study Found Plastic in Every Seafood Sample It Analyzed,” Medical News Today, August 29, 2020, https://www.medicalnewstoday.com/articles/study-found-plastic-in-every-seafood-sample-it-analyzed.

Graham Readfearn, “More Than 14m Tonnes of Plastic Believed to Be at the Bottom of the Ocean,” The Guardian, October 5, 2020, www.theguardian.com/environment/2020/oct/06/more-than-14m-tonnes-of-plastic-believed-to-be-at-the-bottom-of-the-ocean.

Student Researcher: Eduardo Amador (Sonoma State University)

Faculty Evaluator: Peter Phillips (Sonoma State University)