Austrlian Science and Media Centre (AusSMC) has reported that humans consume more than 74,000 microplastic particles each year, according to Canadian researchers, but the impact this has on our health is still unclear. Researchers reviewed 26 previous studies which analysed the amount of microparticles in fish, shellfish, added sugars, salts, alcohol, tap or bottled water and air, and estimated average consumption based on recommended American dietary guidelines.

They found people consume between 74,000 and 120,000 particles each year, depending on age and sex, and people who drink only bottled water could consume an additional 90,000 microplastics per year compared to those who drink only tap water. These values are likely underestimated as the figures only account for around 15 per cent of Americans’ calorific intake, the researchers say.

“The work clearly highlights that micro-sized plastic pieces are pervasive pollutants and not only confined to the world’s oceans, and it is a valuable stepping stone in understanding human exposure.

Humans are certainly exposed to microplastics through food and air. It is important to understand that the particle exposure numbers presented are a current best guess based on a narrow number of studies. The authors rightly point out the large amount of variation in their estimates and make known current limitations in the methods used to quantify plastic exposure in consumed items.

For this to be addressed, we need measurement techniques that can quantify the smaller particles, and we need to understand the measurement uncertainty associated with microplastic analysis. Without a knowledge of the uncertainty, it is impossible to know what confidence can be placed on the reported data and it is challenging to assess the comparability of different measurements.

“This is an emerging but rapidly progressing field of science where improved techniques for assessing exposure levels and burdens is key. Once we better understand human exposure levels then we can begin to comprehend whether there are any health effects from consuming microplastics.” Professor Kevin Thomas, a Director of the Queensland Alliance for Environmental Health Sciences (QAEHS) at the University of Queensland.

“Plastics in the environment are a serious environmental issue. Wildlife is killed by ingesting plastic, usually due to (macro)plastic causing blockages in their stomachs.

There is some evolving research into health effects due to plastic ingestion at the cellular level in wildlife studies. Usually the exposure-to-plastic levels in wildlife to detect these cellular effects are quite high (much higher than I expect you would find in humans).” said Dr Lauren Roman is a CSIRO Postdoctoral researcher at the Graduated Institute for Marine and Antarctic Studies, University of Tasmania

“This new study once again highlights the pervasive nature of microplastics in the global environment. While once thought to be limited to impacts on the natural world, microplastic pollution is beginning to become a detriment to humans too.

The study emphasises a number of disturbing trends that show that humans are consuming vast amounts of microplastic material through diet.

Humans are highly mobile, so ingestion and then excretion of food and water containing microplastics presents an opportunity for humans to act as vectors to further spread microplastics around the world.

Not only this, ingesting microplastics may be placing humans at risk of exposure to the various chemicals found within the plastic compounds. This is particularly problematic and concerning for those who are more sensitive to environmental toxins including children and pregnant mothers.” said Dr Paul an Environmental Scientist and Environmental Chemist.

“This is an interesting and well-reasoned study predicting the possible level of exposure of humans to microplastics (particles of plastic less than 5 millimeters long) via food and drink.

However, while the numbers might at first sound quite scary it should be kept in mind that this work is only an estimate of possible consumption, in the USA, and is based on extrapolation rather than direct measurements. And the authors are good enough to admit there is also a lot of variation in the data.

Even if the values for microplastic consumption are correct, they tell us nothing about any potential health effects, if any.

No harm has yet been demonstrated to humans from microplastics. Indeed, previous research estimated that humans get more exposure to microplastics from dust than food.

That said, the data are certainly a wake-up call to the potential scale of the problem. Microplastics are an area where more science is welcome as we simply don’t yet know enough about the issue to make robust conclusions about the possible risk” – Professor Oliver Jones is an Associate Professor of Analytical Chemistry at RMIT University in Melbourne, Australia.