Microplastics and nanoplastics are small plastic particles, invisible to the naked eye, that come from the degradation of plastics. They’re now found in everything from marine life to soil.
And the spotlight is now on food. Plastic makes up the majority of food packaging: and it’s now one of the most direct and recurrent pathways of plastic exposure in everyday life, according to Earth Action.
A new study from the organisation has found that 1,000 tonnes of microplastics and nanoplastics move from plastic packaging into food and drinks every year. That’s around the weight of more than 600 cars, or, for each high-use individual, more than a gram of particles ingested a year.
The presence of microplastics is uncontested.
Their effect on the human body, however, is less clear.
Plastic bottles
Plastic bottles are particularly in the spotlight. They’re a key component of the beverage industry, and have been a staple of many different types of drinks for many years.
And, according to Earth Action, they’re also one of the bigger shedders of microplastics.
Once they’re bought by consumers, they’re subject to all sorts of rigours and pressures: being carried around, squeezed and crushed, bashed and dropped.
They’re also prone to be left in hot cars or under UV rays - factors which can also affect microplastic shredding.
And, furthermore, the simple action of screwing and unscrewing the top of a bottle can provoke shedding.
Tight regulations
But PET plastic is not new. And it’s one of the most studied food-contact materials in the world, points out Laura Stewart, executive director of NAPCOR, the trade association for PET packaging in the US, Canada and Mexico.
It is subject to rigorous regulatory oversight to ensure consumer safety. Regulatory agencies, including the US Food and Drug Administration and the European Food Safety Authority, continue to state that PET is chemically inert and safe.
“Many studies examining microplastics continue to face significant methodological limitations, including inconsistent measurement standards, challenges in distinguishing environmental contamination from packaging sources, and uncertainty around real-world exposure impacts,” said Stewart.
That, she believes, has been a problem with the Earth Action report.
NAPCOR on Earth Action report
"While continued research into microplastics is critical, the article presents conclusions that go beyond what current scientific evidence can reliably support, assigning disproportionate responsibility to PET (polyethylene terephthalate) packaging and risking overstating conclusions that are not yet supported by scientific consensus.
"The Earth Action report also relies on modeled exposure assumptions and selective interpretations of the scientific literature that diverge significantly from several widely cited peer-reviewed reviews on microplastics exposure. Many of the studies referenced use inconsistent methodologies, unrealistic experimental exposure conditions, or analytical techniques that are not standardized across laboratories."
- Laura Stewart
It all comes down to a key question for microplastics. Their presence is not disputed: but their impact on health is still under assessment.
Stewart says that, in a number of studies referenced by Earth Action, “broad health implications are inferred from particle detection alone, despite the absence of demonstrated causal evidence linking PET food packaging to adverse human health outcomes under real-world conditions”.
Earth Action: 'Absence of proof is not evidence of safety'
Julien Boucher, co-founder of Earth Action, knows this argument well. But he counters: 'absence of proof is not evidence of safety'.
"I think what we can say, to be fact-based, is that we know the emission of microplastics and nanoplastics in food is widespread. You find microplastics and nanoplastics everywhere.
"And we're learning, more and more, that these same microplastics are being found in the human body."
But for Laura Stewart of NAPCOR, it's also about fully understanding the issue. "Consumers deserve reporting grounded in balanced science, not alarming headlines that may oversimplify a highly complex issue."
There’s two key concerns around health. First is the effect of microplastics and nanoplastics on the body: with particles identified often smaller than 150 micrometres and small enough to penetrate cell barriers and thus potentially interact with biological systems.
Then there is the question of chemical leeching: with chemicals from plastics and their manufacture (such as additives for colour) under question.
More research is needed
So what’s the answer? Both Earth Action and NAPCOR can agree on one thing: more studies are needed.
But it’s not just about each study, says Stewart of NAPCOR: it’s about building up a body of research. And for that to have any meaning, these need to have standardized methodologies.
“Many regulatory and scientific bodies continue to emphasize the need for validated testing methods, harmonized definitions, and material-specific analysis before drawing sweeping conclusions about risk," she said.
