Do we really eat a credit card worth of microplastics every week?

The impact of microplastics and the chemicals they carry on human health is a growing concern – many of us have wondered whether we should ditch our plastic chopping boards and containers for something less likely to leech into our systems. You might have even seen eyebrow-raising headlines about just how much plastic we consume, including a popular claim that the average person now consumes a credit card worth of plastic each week.

Just how much truth is there to these claims? Are we really putting ourselves at risk when we reheat our leftovers, or is this all just over-inflated plastic panic?

Thankfully, UQ’s world-leading Minderoo Centre – Plastics and Human Heath is dedicated to answering exactly these kinds of questions. Contact sat down with Centre lead and Director of the Queensland Alliance for Environmental Health Sciences Professor Kevin Thomas to understand the latest in this emerging field of research.

 Key points

• Although we know that some plastic chemicals harm human health, the research is strengthening in what it can tell us about the harms of microplastics. There is enough significant concern to make limiting consumption time critical.
• The science isn’t black and white, but it’s very unlikely that you’re eating a credit card worth of plastics each week.
• However, not knowing does not mean something is safe and a precautionary approach is recommended. It’s a good idea to swap plastics for other options like stainless steel and wood in the kitchen.
• Silicone is less likely to release microplastics than regular plastic – so is another good alternative.

Q: True or false: The average person eats a credit card worth of microplastics every week.

This claim is widely circulated, but its accuracy is debated. Some studies estimate that humans ingest about 5 grams of microplastics weekly, roughly the weight of a credit card. However, other experts argue that this figure might be an overestimate.

Our research suggests that, for the typical Australian food basket, this figure is a significant overestimate – a key challenge in estimating exposure being the dispersed nature (heterogeneity) of plastic particles in foods and beverages.

Q: Should we ditch plastic containers and chopping boards? What about silicone kitchen items?

Plastic containers and chopping boards can release microplastics, especially when scratched or exposed to heat. Switching to alternatives like glass or stainless steel for containers and wooden or bamboo chopping boards can help.

 Silicone kitchen items are generally considered safer as they don’t release microplastics under normal use.

Q: What simple actions can we all take to reduce the risk of consuming microplastics?

1. Use reusable alternatives to single-use plastics.
2. Avoid heating food in plastic containers.
3. Choose natural fabrics for clothing and home textiles to reduce microfibre pollution.

Q: What potential harms are associated with human exposure to microplastics?

This is a leading field of work. Lab studies have shown that exposing cells to nanoplastics can cause many changes – for example, changes similar to those found in people with Parkinson’s disease.

However, to understand how nanoplastics and microplastics might impact our health, we need to better understand whether they can be absorbed by the human body. Current research continues to explore this area.

Q: Given the limited evidence we currently have, why is it still important to limit exposure?

Micro- and nanoplastics are everywhere in our environment, and they can carry harmful chemicals like Bisphenol A (BPA) and phthalates. These chemicals are known to disrupt hormones and may increase the risk of developmental problems in children.

Q: What is the most surprising fact you’ve encountered in this field so far, regarding microplastics and how they impact humans and our environment?

A recent study suggested that there could be as much as 4.5 polyethylene bottle caps worth of plastic in a person's brain, but this claim doesn't make sense biologically and only highlights the current uncertainty about which findings can be trusted and what they mean.

Together with colleagues from Europe, we recently published an article in the journal Nature calling for more rigorous research in this area. Additionally, we partnered with Minderoo Foundation to host a workshop in March aimed at reaching a consensus on key questions such as biological plausibility, background contamination, communicating confidence and data availability. Our goal is developing a comprehensive reporting checklist for scientists, and journal editors and reviewers.

Q: Tell us more about the work of the Minderoo Centre – Plastics and Human Health. How is the lab contributing to this emerging and important field of research?

The Minderoo Centre – Plastics and Human Health at UQ is dedicated to understanding human exposure to plastic particles and chemicals. Established in partnership with Minderoo Foundation, the Centre focuses on developing methods to accurately sample and measure plastic chemicals and particles in humans, including in the brain. The Centre brings together experts in environmental health, toxicology, epidemiology and other fields to advance our understanding of the health outcomes associated with plastic exposure.

We work closely with the Sydney Brain Bank and other health specialists. Some of our key activities include: developing sensitive detection methods; creating techniques to detect plastics and plastic chemicals in blood, urine and brain tissues; and partnering with international researchers to publish findings and set standards for plastic exposure studies. The Centre aims to provide a clearer picture of how plastics affect human health and to inform strategies for reducing exposure.

Thanks to Minderoo Foundation, we have outstanding facilities at UQ Dutton Park that enable this research including our award-winning plastics contamination-controlled lab [pictured below] to minimise background contamination of our samples and sensitive instruments to measure the plastics and associated chemicals.

Background image: Adobe Stock / Amafcoffee