Do You Eat a Credit Card of Plastic Per Week?

You may have seen this claim. You may believe this claim.

If you want an answer in short: no, probably not. If you want a (slightly) longer explanation as to why, read on.

You eat a credit card - how was it reported?

Many outlets have reported on this, for example:

OUTLET	TITLE	IN THE ARTICLE
Reuters, June 2019	You may be eating a credit card's worth of plastic each week: study	"Plastic pollution is so widespread in the environment that you may be ingesting five grams a week, the equivalent of eating a credit card"
WEForum, June 2019	You eat a cred card's worth of plastic a week, research says	"new research shows you probably ingest that weight of plastic a week without realizing"
The Telegraph, June 2019	Average person swallows plastic equivalent to a credit card every week, report finds	"The average person now ingests five grams of plastic each week, the equivalent of a credit card, a new report by WWF has found"
Reuters, December 2020	How much plastic are you eating?	"People could be ingesting the equivalent of a credit card of plastic a week ... In a month, we ingest the weight of a 4x2 Lego brick in plastic, and in a year, the amount of plastic in a fireman's helmet."
New York Post, December 2020	You’re eating a horrifying amount of plastic and didn’t even know it	A video starts with a credit card in a ceral bowl, with milk poured on top.
The Guardian, February 2022	Australians ingest a credit card’s worth of plastic a week – so what’s it doing to us?	"On average, we ingest about one credit card’s worth of plastic a week"
The Independent, April 2022	Warning over ‘irreversible’ health risk from plastics as humans ‘eat one credit card a week’	"previous work which suggested that people in some areas of the world consume around five grams of MNPs [micro- and nano-plastics] per week - equivalent to a credit card"

Other articles have also included images over 'periods of time' showing a provocative series of photographs in which this credit card figure is then scaled up. For example, stating:

At this rate of consumption, in a decade, we could be eating 2.5 kg (5.5 lb) in plastic, the equivalent of over two sizable pieces of plastic pipe

What did the original research show?

The origin is 2019 report from the WWF - conducted by Dalberg & The University of Newcastle, Australia - titled "No Plastic in Nature: Assessing Plastic Ingestion from Nature to People". The report states:

An average person could be ingesting approximately 5 grams of plastic per week. The equivalent of one credit card.

The study reveals that consumption of common food and beverages may result in a weekly ingestion of approximately 5 grams of plastic, depending on consumption habits.

It is incredibly important to look at the wording, here that is again with some emphasis added:

An average person could be ingesting approximately 5 grams of plastic per week. The equivalent of one credit card.

The study reveals that consumption of common food and beverages may result in a weekly ingestion of approximately 5 grams of plastic, depending on consumption habits.

That's a lot of caveats. Moreover, in the highlighted box of the report titled: "Study methodology and limitations":

The consensus among specialists is thus that while these numbers are in a realistic range, further studies are needed to get a precise estimate

The scientific research was published later, in February 2021: Estimation of the mass of microplastics ingested – A pivotal first step towards human health risk assessment[1].

The conclusion is a perfect summary of why such findings should be carefully read (emphasis mine):

the analysis indicates that globally, on average, humans could potentially be ingesting 0.1–5 g of microplastics per week. The amount of the microplastics ingested by an individual will depend on a combination of highly variable parameters, not only of the characteristics of the microplastics but also to each individual's age, size, demographics, cultural heritage, geographic location, nature of the development of surrounding environment and lifestyle options.

What has analysis of this research shown?

A study (March 2021)[2] on microplastic accumulation in humans stated compared results to their own work and found that the 5g per week estimate was above the 99th percentile of their distribution and so does not represent the intake of an average person.

You can see this most clearly in their publication figure below. [Alternatively in the original publication here or a high res direct image: here]. The area between the black dashed lines indicate the area where WWF study estimates lie, while the thick red and green sections show where the other studies findings were most likely. Orders of magnitude lower.

The grey shaded area bound by black dashed lines shows the range of mass intake estimation by WWF

Source: Lifetime Accumulation of Microplastic in Children and Adults, March 16 2021, Environmental Science & Technology, Vol. 55, Issue 8. N. H. M. Nor, M .Kooi, N. J. Diepens, and A. A. Koelmans. Available at: https://pubs.acs.org/doi/10.1021/acs.est.0c07384

This analysis from Wageningen researchers estimated that on average we consume less than one salt grain's worth of microplastics a week. You can see their press release here.[3]

Summary: The Journey of "Eating a Credit Card"

This claim has gone on a tumultuous journey. From stating that we consume:

"globally, on average, humans could potentially be ingesting 0.1–5 g of microplastics per week"

to

Up to 5 g per week

to

5 g on average every week

to

We ingest a LEGO brick every month

BUT WHAT DOES THIS MEAN?

That the claim is highly unlikely based on probability from the original study.

Moreover, that taking an improbable figure and then extrapolating that - making it even more unlikely - is sensationalism. It may engage readers and improve tangibility, but that does not mean credibility.

This is not stating we do not consume microplastics, or that there is no issue with consuming microplastics, but that the study findings have become disconnected with the reporting of them.

Ignoring the science, the actual claims, the methods, the caveats and limitations - is precisely what we do NOT want to be doing.

REFERENCES

[1] Estimation of the mass of microplastics ingested – A pivotal first step towards human health risk assessment, 15 February 2021, Journal of Hazardous Materials, Vol. 404, Part B, 124004. K. Senathirajah, S. Attwood, G. Bhagwat, M. Carbery, S. Wilson, T. Palanisami. Available at: https://doi.org/10.1016/j.jhazmat.2020.124004

[2]  Lifetime Accumulation of Microplastic in Children and Adults, 16 March 2021, Environmental Science & Technology, Vol. 55, Issue 8. N. H. M. Nor, M .Kooi, N. J. Diepens, and A. A. Koelmans. Available at: https://pubs.acs.org/doi/10.1021/acs.est.0c07384

[3] Humans consume less than one salt grain of microplastic per week. Wageningen University, 2021. Available at: https://edepot.wur.nl/548802

BIBLIOGRAPHY

Other useful reading checking this claim include:

Anja Krieger - Is it true that we consume up to a credit card’s worth of plastic every week? 

27 November 2023. Anja hosts the Plastisphere Podcast - a podcast on plastic pollution in the environment.

Helmholtz-Zentrum Hereon - Is it true that we consume up to a credit card’s worth of plastic every week? Certainly false X. 13 October 2023.

Bart Koelmans of Wageningen University. Responsible for the Wageningen research and press release. See their research page here: https://research.wur.nl/en/clippings/humans-consume-less-than-one-salt-grain-of-microplastic-per-week

FullFact - You do not inhale a credit card’s worth of microplastic every week. 14 March 2024.