An international team of researchers, led by The University of Queensland and Imperial College London, has proposed a new framework for scientists detecting and measuring microplastics in the human body.
The research has been supported by Australian philanthropic organisation Minderoo Foundation.
Thirty scientists from 20 institutions have proposed the new forensic-style protocol and urge careful interpretation of recent reports about the presence of microplastics in human tissues.
Professor Kevin Thomas from UQ's Queensland Alliance for Environmental Health Science said there is an urgent need to develop accurate and precise methods of investigating microplastics in the body to protect human health.
"Each current method has strengths and blind spots,'' Professor Thomas said.
"One of the best ways to build confidence is to use more than one kind of test on the same sample, particularly methods that work in different ways.
"When they all point to the same result, we can be far more confident we're truly detecting plastic rather than something else.''
Professor Thomas said human tissues and fluids contained several different natural substances that can interfere with measurements.
Samples can also easily be contaminated with plastic from the air, from clothing or from laboratory equipment.
"In some cases, commonly used techniques can struggle to distinguish plastics from natural materials like fats or other biological components,'' Professor Thomas said.
"In addition, several methods destroy the sample during testing, meaning that additional analysis cannot be performed to improve the confidence.
"As a result, these challenges mean that not every reported 'plastic particle' can be treated as definitive proof.''
Professor Leon Barron, from Imperial College London's School of Public Health, said human exposure to micro and nanoplastic pollution was a global issue.
"It is important to understand their impacts, but when it comes to the human body, tools are still only developing,'' Professor Barron said.
"Finding 'something' in the human body is not the same as proving it is plastic, and certainly not the same as proving it is harmful.
"Basic science gaps still exist, and it is important to work together to reach consensus first to improve the quality and communication of evidence.
"Thankfully, we can learn a lot from other fields, such as forensic science, where combining different testing tools together in a more robust way has been used successfully for decades.
"These offer more evidential value and higher confidence to scientists so the public, health professionals and policymakers can make reliable decisions."
Professor Sarah Dunlop from the Minderoo Foundation said: "We know that every day we eat, drink and breath in microplastics.
"Accurate measurement is mission critical to find out how far microplastics penetrate our bodies and impact human health."
Professor Thomas said building a solid evidence base now will pay off in the future.
"People understandably want clear answers about microplastics and health,'' he said.
"By being honest about what we know, what we suspect, and what we still don't know, we can support smarter policies and avoid unnecessary fear.
"Strong, forensics-style standards today will lead to much stronger science tomorrow."
The research is published in Environment & Health.
Collaboration and acknowledgements
The research was co-led by the Imperial College London's School of Public Health, with support by the Minderoo Foundation.
