Is it true that we ingest and inhale a credit card's worth of plastic every week?
This claim is certainly false. It is true that plastics have been found in the human body. Microplastics can be ingested through food or drinks, and inhaled from the air. However, the average quantity of plastic which enters the human body is unclear. Scientific estimates still differ strongly, however there is no doubt that ‘one credit card per week’ is a gross overestimate. For example, another study estimates that humans eat less than the equivalent of a grain of salt per week - much less than a credit card.
Detailed information
In 2019, the results of a study commissioned by the environmental organization WWF were published. One of the study’s main assumptions, regarding the mean mass of microplastics eaten and inhaled by people, was flawed and resulted in very high mass estimates. The WWF highlighted only the highest estimate from this study.
This led to the ‘plastic credit-card’ comparison spreading swiftly on media outlets and social media. For example, news agency Reuters turned this claim into an infographic story titled “A plateful of plastic: Visualising the amount of microplastic we eat” using shredded plastics and kitchen utensils to illustrate the quantity of 5 grams per week over time.
However, other researchers have arrived at quite different estimates. For example, one study estimates that people might consume at most the mass of a few milligrams a day, in the form of several hundreds of tiny particles of plastics. The exact amount of human intake is still uncertain, as well as the impacts on human health.
Expert check
Thanks toBart Koelmans of Wageningen University andPeter Ryan of the University of Cape Town for scientific fact-checking.
Updated on: October 15, 2024