By Angus Dalton
Exposure to microplastics has been linked to lung and colon cancer in a major scientific review led by a Sydney expert who screened 3000 studies to draw conclusions into the health effects of the tiny, ubiquitous pollutants.
Microplastics are also suspected to damage sperm quality and ovarian follicle development, and the review found higher levels of plastics were linked to increased gut inflammation and lung injury.
Exposure to microplastics has been linked with lung cancer.Credit: Marija Ercegovac
“Unless we turn the tap off now and we ban all single-use, non-essential plastic … we are going to have one of the great human crises in the next 20 or 30 years,” Dr Nicholas Chartres, lead author of the study from the University of Sydney, said.
Microplastics are shards of plastic less than 5 millimetres long. Many are small enough to enter the bloodstream. We breathe in or consume fragments leached by plastic containers, torn from tires and shed from synthetic clothes and blankets.
Scientists have detected plastic in almost every human tissue, including hearts, placentas, bone marrow, testicles and the brain.
But the research on health effects is nascent.
Sydney University research fellow Dr Nick Chartres called for an end to non-essential plastics.Credit: Nick Moir
An influential study in March found half of people undergoing surgery for clogged arteries had blood vessels riddled with microplastics, and those patients had a greater chance of heart attack, stroke and death. Otherwise, large and long-term studies in humans are rare.
Most studies in the review were based on rats and mice. Results from animals are considered lower-quality evidence compared to human studies because effects observed in rodents often don’t manifest in people.
However, Chartres said most of the research papers, when taken together and analysed for risk of bias, had results pointing in the same direction – the greater exposure to microplastics, the greater health risks suffered.
“This data is as good as it gets in terms of being able to draw these early conclusions on health effects. We can’t ethically expose human beings to contaminants like this,” Chartres said.
“In these animal studies, both in the colon and also in the lung, there are high levels of chronic inflammation consistently across all these study results. They are early predictors of getting cancer.”
American microplastics researcher Professor Matthew Campen, however, said it was too early to assess human health risks based on available data.
“We are still learning about the nature of the plastics in the human body and there is a lot of published research based on shaky assumptions,” he told The Washington Post.
Chartres said he would continue adding to the review as more results are published. But the data was strong enough, he said, for governments to act now.
“I don’t want to wait 10 years until I can give you another 30 studies in humans to show that it’s a carcinogen, and we’ve all got five times the amount of plastic in our systems,” he said.
“[Fossil fuel industries] are going to be trying to ramp up production of plastic, because that’s where they’ll be turning the fossil fuel they extract into money.”
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