The Woolcock Institute of Medical Research

Research highlighting the widespread contamination of our food, water and air with microplastic particles has led to growing public awareness of environmental harms and potential health risks. What do we know, so far, about the risks when it comes to respiratory disease?

Distinguished Professor Brian Oliver, research leader of the Woolcock’s Respiratory Cellular and Molecular Biology group says human exposure to microplastics can be through what we drink, what we eat and in the air we breathe.

“From a respiratory perspective, you would think that the ones in the air are the most important. How do they get in the air and who’s at risk of exposure? Well, if you’re a worker in a plastic recycling plant, there’s likely to be aerosolisation of small bits of plastic but when it comes to most of us, the most obvious source of microplastic is from roads, coming from rubber tyres on vehicles.”

“BREAKING UP” IS HARD

According to Professor Oliver, the stable nature of plastics means that they require a lot of force to “break up”. For example with rubber products, heavy braking and the shear volume of traffic on our roads are reasons for microplastic generation, whereas rubber-soled shoes on concrete or running on recycled plastic playground surfaces would be a minor contributor to microplastics in the air.

And then, it’s a matter of the level of microplastics.

“We know that if we look in the air, we do find microplastics and we find them in both urban and rural areas. We also know that they are found at increased levels around industrial areas and major roads and we also find them in human tissue (including the lung). This is where it gets interesting because studies have shown that the amount of microplastic found in the lung (as well as the brain and liver) doesn’t increase with age, so we believe the body has a way of eliminating it. It gets rid of the excess.”

Plastic itself is relatively inert, he says, so any risk is likely to come from microplastics being a “transport mechanism” for heavy metals from, for example, dust created by brake wear or endotoxins from bacteria which cause inflammation. The size or shape of particles may also come into play but the levels of microplastics in the air is still relatively low in comparison to other forms of air pollution.

MORE TO FEAR, MORE TO KNOW

“Anyone with severe respiratory illness like asthma or COPD should be avoiding those areas already. Microplastics are not really the thing they ought to be concerned about. I do think, to some extent, we’re hearing a lot about them right now simply because it’s such a new area of research when it comes to our lungs - only about five years.”

“We’re at the start of our understanding of microplastics. Compared to 10 years ago, there are more microplastics in the environment which translates to more microplastic in our bodies. We know that we find them in tumours. We know that the brains of people with dementia have up to four times more microplastic, but that’s not causation. It may be that microplastics have contributed to the development of dementia or it may be that the process of eliminating them from the brain is aberrant in dementia.”

There hasn’t been enough research in humans for us to really know, he says.

“It’s fair to say this research is in its infancy. We do need research so we can better understand the nature of microplastics but I’m pretty certain that if your exposure is limited to the urban environment, then there are other things in the air that I would be much more concerned about.”

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• Our Respiratory Cellular and Molecular Biology Research Group