Dietitian Susie Burrell shares fears about microplastics

A dietitian has cautioned Aussies against using plastic containers and plastic drink bottles for fear they are leaching microplastics into our system.

Susie Burrell, who has two honours degrees in nutrition and dietetics and psychology, spoke on her podcast The Nutrition Couch with fellow expert Leanne Ward about a recent eye-opening stydy.

The University of Queensland found that Australians are eating a credit card-sized amount of plastic every year, namely through pre-packaged rice and heating up meals in plastic containers.

‘Microplastics – tiny pieces of plastic less than 0.2 of an inch (5mm) in diameter -come from many sources: synthetic clothing fibres, dust from tyres, road paints, and the breakdown of larger items,’ Susie said.

‘Orb Media’s recent investigation has brought the issue of microplastics in the environment into sharp focus. The analysis of tap water samples from around the world found that a high proportion of drinking water is contaminated with microscopic fragments of plastic (83 per cent of samples collected worldwide, but up to 94 per cent in the USA). 

‘Microplastic contamination seems more widespread than we perhaps knew, and they are regularly being ingested by people worldwide. 

‘Most concerning is how little is known about the effects of microplastic consumption on human health. It is no small problem.’

As of 2015, 6300 million tonnes of plastic waste have been generated, around nine per cent of which was recycled, 12 per cent was incinerated, and 79 per cent ended up in landfills or the environment. 

The issue of large plastic items polluting the world’s oceans is well-known, leading to policies that aim to limit the production and use of plastic bags and bottles, and increase recycling. 

However, a key problem with plastics is that they are essentially indestructible; rather than being biodegraded, they break down into smaller and smaller pieces, eventually becoming microscopic fragments. 

‘We should no longer just be concerned with large plastic items clogging up oceans and waterways, but also more attention needs to be paid to these tiny fragments and their effects on planetary health,’ Susie said.

‘The tapwater study is not the first to indicate that microplastics are being consumed by humans. 

‘A 2014 study of German beer brands found that microplastics were present in all of the samples, and a Parisian study showed microplastics not just in water but also in the air. 

‘Microplastics are also routinely ingested by fish and shellfish. 

‘But the apparent widespread presence of microplastics in tapwater is particularly concerning because it points to substantial contamination of terrestrial and freshwater – as well as marine – ecosystems.’

To date, there have been no studies of the effects of microplastic consumption by humans. 

Designing robust studies to look at this issue will be difficult – observational, population-based studies will be open to confounding, while experimental studies will be impractical (ethically, if nothing else), Susie explained.

‘The deleterious effect of current levels of microplastics might be small, by contrast with the known risks of industrial pollutants such as heavy metals or black carbon, so teasing out the effect at the population level will be hard, and will require a sophisticated surveillance system,’ she said.

‘If an effect exists, people living in areas of high plastic contamination will develop greater disease burdens as levels continue to rise. 

‘Disease-reporting systems need to be linked to pollution databases to ensure any effect is identified early, and action taken quickly. Solving a problem of this magnitude will not be an easy task. 

‘Public education, product innovation, and industry leadership along with strong commitment from local, national and international governments, are urgently needed to reduce the use of microplastics and to understand the effects of these particles on both ecosystems and the human body.’

In April microplastics were discovered in live human lungs for the first time – proving we are breathing them in from the air. 

Researchers from the University of Hull and Hull York Medical School found microplastics in the deepest section of the lung.

This was previously thought to be impossible, due to how narrow the airways are. 

While particles have been found in human cadaver autopsy samples before, this is the first time they have been found in the lungs of live people. 

The study comes shortly after microplastics were discovered in human blood for the first time, highlighting just how widespread the particles now are in the human body.

The research team say the findings show that inhaling microplastics is a route of exposure and will now help direct future studies on the impact microplastics could have on respiratory health.

The study, which has been published in Science of the Total Environment, found 39 microplastics in 11 of the 13 lung tissue samples tested – considerably higher than any previous laboratory tests.

Laura Sadofsky, lead author on the paper, said: ‘Microplastics have previously been found in human cadaver autopsy samples; this is the first robust study to show microplastics in lungs from live people.

‘It also shows that they are in the lower parts of the lung. Lung airways are very narrow so no-one thought they could possibly get there, but they clearly have.

‘This data provides an important advance in the field of air pollution, microplastics and human health.

‘The characterisation of types and levels of microplastics we have found can now inform realistic conditions for laboratory exposure experiments with the aim of determining health impacts.’

Surgeons at Castle Hill Hospital in East Yorkshire supplied the live lung tissue, which was collected from surgical procedures carried out on patients who were still alive, as part of their routine medical care. It was then filtered to see what was present.

Of the microplastics detected, there were 12 types, which are commonly found in packaging, bottles, clothing, rope/twine, and many manufacturing processes.

There were also considerably higher levels of microplastics in male patients compared with females.

The study showed 11 microplastics were found in the upper part of the lung, seven in the mid part, and 21 in the lower part of the lung – which was an unexpected finding.

Ms Sadofsky said: ‘We did not expect to find the highest number of particles in the lower regions of the lungs, or particles of the sizes we found.

‘This is surprising as the airways are smaller in the lower parts of the lungs and we would have expected particles of these sizes to be filtered out or trapped before getting this deep into the lungs.’

The study follows research published in March by the University of Hull and Hull York Medical School in which scientists recorded high levels of atmospheric microplastics during a year-long study at a site close to a busy northern trunk road.

Researchers found the most abundant microplastics were polyethylene from, for example, degraded plastic packaging or carrier bags; nylon, which may be from clothes; as well as resins, which could come from degraded roads, paint marking or tyre rubber.

They also found microplastics of the size and shape which are inhalable by humans.