A plastic pestilence
While ingesting microplastics is not yet a proven health risk, isn’t it better to be sure? David Burrows reports
Two years ago, the Ellen MacArthur Foundation published a report on global use – and misuse – of plastic. It covered 117 pages, but this bit grabbed the headlines: “The best research currently available estimates that there are over 150 million tonnes of plastics in the ocean today. In a business-as-usual scenario, the ocean is expected to contain one tonne of plastic for every three tonnes of fish by 2025, and, by 2050, more plastics than fish (by weight).”
Think about that for a minute (and while you do so another rubbish truck’s worth of plastic will ‘leak’ into the ocean). In fact, of the 78 million tonnes of plastic packaging produced every year, almost a third (32%) ends up in the environment (and that’s only one source of plastic pollution – there are also pre-production plastic pellets, microbeads in cosmetics, textiles and car tyres). Once there, it can be gobbled up by a variety of marine life – in big chunks (as the BBC’s
Blue Planet II series showed) or in much smaller quantities as it breaks down into ‘microplastics’ or as even smaller nanoparticles.
It’s not good news for wildlife. In a recent review of the literature to date, the United Nations Food and Agriculture Organization (FAO) found that over 220 different marine species ingest microplastic debris ‘in natura’. That’s concerning, but here’s the kicker: take out the birds, turtles and mammals and 55% are species of commercial importance – Norway lobster, oysters, sardines and Atlantic cod.
“Human intake of microplastics from seafood (ie mussels) has been estimated to equal anything from one particle per day to 30 particles per day depending on seafood consumption habits and exposure of organisms to microplastics,” the authors noted.
And it’s not just your mackerel on toast that is bringing an unwanted helping of plastic pieces – contamination has also been found in honey, sea salt and beer. Indeed, wherever scientists look they seem to find plastics – including tap water. The results of a study published by Orb Media in September showed that microplastics were present in 72% of the samples taken in European countries – an average 500ml glass of water for example contains 1.9 plastic fibres.
So is this plastic plague just an environmental crisis, or is it a human health concern too? And, if so, will it trigger politicians and businesses to introduce swift, deep, global policies to curb plastic use and pollution?
The short answer is: we don’t know. Looking on the bright side, the levels of contamination are low. In the case of seafood, for example, the gut is where most microplastics end up, and that’s often removed before consumption. When it’s not, a ‘worst case’ estimate of exposure to microplastics when eating a portion of mussels would be 7μg of plastics. It’s not enough to cause concern. The European Food Safety Authority (EFSA) came to the same conclusion: in its May 2016 analysis, experts concluded it “seems unlikely” that microplastics could be harmful to consumers.
Lack of data
But there is a longer, more complicated answer that considers all the ifs, buts and maybes created by what regulators and researchers admit is a lack of data – especially on the very smallest particles. “We know that engineered nanoparticles (from different types of nanomaterials) can enter human cells, so this may have consequences for human health. But more research and data are needed,” said Dr Peter Hollman, one of the experts that produced EFSA’s assessment.
Researchers at Lund University, Sweden, have since discovered that nano-sized plastic particles can accumulate in fish brains and cause damage. Whether they could also accumulate in other tissues that are then eaten by us isn’t yet clear, but while the evidence to prove human harm isn’t there, there is plenty to suggest it’s a possibility.
“There is enough information that this is having an impact and has the potential to have a very serious impact,” Dr Sherri Mason, a professor of chemistry at the State University of New York, told me recently.
Indeed, what makes plastics interesting is their ability to suck up pollutants (including those that are now banned but still hanging around) as they float around in the sea. Chemicals – like bisphenol A, recognised as an endocrine disruptor and currently the subject of intense scrutiny in Brussels – are also added to packaging. Studying the impact these tiny ticking chemical cocktail bombs have as they are ingested and passed up the food chain is far from easy. “It’s called a food web for a reason,” Mason says. “It’s so interconnected, and trying to untangle it is a little insane, but that’s what we do.”
However, so far, they have only scratched the surface. There is an urgent need for bigger, better, and more definitive studies, as Stephanie Wright from King’s College London pointed out in a piece for the British Medical Journal in September. “Only a fraction of dietary components – shellfish, salt, honey, sugar, beer, tap water – have been tested. We need to establish the toxic characteristics of microplastics, their behaviour in the body, and what constitutes a safe threshold for exposure when plastics are either ingested or inhaled.”
Afraid of what it might find?
EFSA and the Food Standards Agency also say more research is needed, as does the UK government. In October 2016, it said the chief medical officer (CMO) would “over the next year … review the effects on health of pollution of several kinds including microplastics”. This was in response to an investigation by the House of Commons environmental audit committee. The report is still being compiled, and the Department of Health is keen to play down its significance. “The CMO agreed to consider this issue [microplastics] while scoping topics for her next annual report – but never committed to doing specific research on this,” says a spokesman. “The consideration was whether to include this topic in a broader report on pollution and health.” (At time of writing, the CMO’s report has not yet been published).
Is the government afraid of what it might find? For all its recent rhetoric and grand commitments on plastic use and pollution, (the 25-year environment plan, the ban on microbeads, a call for evidence on potential taxes for single-use plastics), there has been no mention of any possible effects on human health. Some believe this to be a major oversight. “This is a very new area of research, and the fact that microplastics persist in the environment, are very mobile and also show signs of accumulating in wildlife is of great concern,” explains Dr Michael Warhurst, executive director at the CHEM Trust. “To put it at its most basic, whatever toxic effects we may find in the future, it is going to be impossible to withdraw all the microplastics from the environment.”
Across the Channel, it’s a different story. “We must stop plastics getting into our water, our food and even our bodies,” said European Commission first vice-president Frans Timmermans when he launched the EU’s plastics strategy in January. Read through the strategy and there are half a dozen references to human health.
This isn’t an attempt to turn the issue into a Daily Mail food scare; rather, it’s a bid to kick member states and businesses into action before it becomes one. In the next 20 years, production of plastic will double, according to the Ellen MacArthur Foundation. “The problem is wide-scale and the concentrations are low,” says Richard Thompson, professor of marine biology at Plymouth University in the UK. “But if we carry on as normal and have this conversation again in 20 years’ time, we may well have reached concentration levels that are a concern.”
For Mason, there are lessons to be learned from climate change policies and “past mistakes” as world leaders dillied and dallied to strike a global commitment. “We are sounding the alarm loudly because of what happened with climate change,” she says. Some concrete new policies on plastic reduction, reuse and recycling would help, but businesses may well have to step up to the plate. Some have wasted no time in bids to become plastic-free pioneers.
Supermarket chain Iceland is to eliminate all plastic packaging from its own-brand products by 2023, for example. “Time is running out for plastic,” read a full-page advert in a January issue of The Guardian. “For over 40 years, we’ve relied on it to package our products. It’s cheap, light and easy. It’s also clogging up our oceans. Harming sea life and getting into the food chain.” The retailer said “future generations shouldn’t have to pay for tonight’s dinner” – especially if it’s riddled with tiny pieces of toxic plastic.
David Burrows is a freelance journalist
Image credit: Ikon