The problem with plastic
Plastic pollution of the oceans is an environmental disaster, but is there a food scare lurking beneath the waves too? Journalist David Burrows reports.
Last year’s Volvo Ocean Race lasted eight months and covered 45,000 nautical miles. En route, one of the teams – “Turn The Tide On Plastics” – diligently collected water samples that could be tested for the presence of microplastics – small pieces of plastic measuring less than 5mm. The data was used to create a microplastics map of the world’s oceans, which highlights just how ubiquitous these particles are: only three of the 75 samples collected contained no microplastics.
Few of those close to the topic of plastic pollution – arguably the environmental issue of 2018 – will have been surprised by the findings. However, it’s worth recapping what we know so far. Each year, at least eight million tonnes of plastics “leak” into the ocean, according to the Ellen MacArthur Foundation (EMF), a think-tank dedicated to driving a “new plastics economy”. To put that in context, that’s about five garbage truckloads in the time it takes to read this article (a rate of one truck per minute). Plastic packaging represents a “major share” of this leakage, according to the EMF; indeed, carry on like this and by 2050 there will be more plastic in the sea than fish (by weight).
“Plastic is everywhere, and suddenly we have decided that is a very bad thing,” noted Stephen Buranyi in an article for The Guardian in November 2018 (“The Plastic Backlash: What’s Behind Our Sudden Rage – And Will It Make A Difference?”). The public is up in arms – thousands of them posted crisp packets back to Walkers, and many more have ripped off excessive packaging at supermarket checkouts in “plastic attacks”. And in the past 12 months only animal welfare and caged poultry attracted more activity from campaign groups, according to tracking firm Sigwatch.
Those in the food sector have been forced to react – many have whipped up new packaging policies and been quick to sign up to industry commitments like the UK Plastics Pact. The development of government policy has also been uncharacteristically rapid too – the UK’s 25-year environment plan, published in January 2018, focused heavily on plastics. A new resources and waste strategy, presented just before Christmas, includes a number of policy proposals designed to reduce single-use items, with consultations underway for bans on cotton bud sticks, drinks stirrers and straws. The European Commission also has a new Plastics Strategy, with additional bans on plastic drinks stirrers and cutlery, as well as food and drink containers made from expanded polystyrene. As Buranyi wrote: “At the highest levels of government the plastic panic can resemble a scrambled response to a natural disaster, or a public health crisis.”
His choice of words is interesting, not least because what started as an environmental disaster is quickly snowballing into a public health crisis. In January 2019, the Science Advice for Policy by European Academies (SAPEA) working group produced the latest review of the evidence to date. “A Scientific Perspective on Microplastics in Nature and Society” concluded that there is “no evidence of widespread risk to human health from [nano and microplastics] at present”. Still, a lack of evidence for risk doesn’t mean we should assume that there is no risk, said SAPEA’s Professor Bart Koelmans. “It’s vital we communicate clearly about uncertainties in the evidence, rather than just assuming that everything is fine just because we don’t know for sure.”
Indeed, wherever researchers have looked in our food and drink chain, they’ve found plastic: honey, beer, bottled and tap water, sea salt and of course seafood. “The problem is wide-scale and the concentrations are low,” Richard Thompson, professor of marine biology at Plymouth University, UK, told me in an interview for EU Observer in December 2017, “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.”
It was Thompson and his team who, all the way back in 2004, showed that waters around the north-east Atlantic had become contaminated by microscopic fragments of plastic and that the abundance of this material had increased significantly over time. In 2013, their research published in the journal Marine Pollution Bulletin showed plastics in 184 of the 504 fish they examined from the English Channel. Species assessed included whiting, horse mackerel, John Dory and red gurnard. There is now a rich library of similar research. In 2016, for example, a study published in the journal Nature, showed that 28% of fish and shellfish on sale in Indonesia had eaten man-made debris – and all of it was plastic. The authors said that because anthropogenic debris is associated with a “cocktail of priority pollutants”, some of which can transfer to animals upon ingestion, their findings support concern that chemicals from man-made debris may be transferring to humans via diets containing fish and shellfish. This, they added, raises important questions regarding the bioaccumulation and biomagnification of chemicals and consequences for human health. Indeed, the tiny plastic particles floating about in the sea can act like sponges for persistent bioaccumulating toxins, so anything that mistakenly eats them gets a shot of this chemical cocktail.
The plastics sector has played this effect down, but the impact this could have further up the food chain is not yet clear. Last year, the journal Current Opinion in Environmental Science & Health ran a special issue on micro- and nanoplastics – the latter measured in the millionths of a millimetre. A paper by Messika Revel, Amélie Châtel and Catherine Mouneyrac reviewed the evidence to date. They concluded that the adverse effects from micro- and nanoplastics may result from a combination of the plastic’s intrinsic toxicity (such as physical damage); chemical composition (for example, the leaching of additives); and ability to adsorb, concentrate, and release environmental pollutants into the organisms. Microplastics could also serve as a vector for pathogens, they said, and since they have been detected in various trophic levels, additional studies are needed to assess the bioaccumulation of adsorbed contaminants and eventually biomagnification, which “may occur in higher trophic levels, and could eventually affect human health”.
In October 2018, experts at the Medical University of Vienna and the Environment Agency Austria published the results of a pilot study involving a small group of participants (eight) from countries across the world, including Finland, Italy, Japan, the Netherlands, Poland, Russia, the UK and Austria. Each person kept a food diary in the week leading up to a stool sampling. The diaries showed that all participants were exposed to plastics by consuming plastic wrapped foods or drinking from plastic bottles. None of the participants were vegetarians and six of them consumed sea fish. Up to nine different plastics, sized between 50 and 500 micrometres, were found, with polypropylene (PP) and polyethylene terephthalate (PET) the most common. On average, the researchers found 20 microplastic particles per 10g of stool. Microplastic may impact human health via the gastrointestinal tract, the team noted, where it could affect the tolerance and immune response of the gut by bioaccumulation or aiding transmission of toxic chemicals and pathogens. Dr Philipp Schwabl led the research. “While the highest plastic concentrations in animal studies have been found in the gut, the smallest microplastic particles are capable of entering the blood stream, lymphatic system and may even reach the liver,” he said. “Now that we have first evidence for microplastics inside humans, we need further research to understand what this means for human health.”
So, the warning signs are there. But what do the regulators and governments’ advisors think? Is the establishment of a ‘safe’ threshold for plastic in water and food on the cards? The most recent opinion published by the European Food Safety Authority (EFSA) on this subject was in 2016. Are they harmful to consumers? “It’s too early to say but it seems unlikely, at least for microplastics,” said Dr Peter Hollman, a member of the working group that helped EFSA’s Panel on Contaminants in the Food Chain (CONTAM) draft the statement. However, nanoplastics, which have received less attention to date, could pose more problems.
“Knowledge on the toxicity of nanoplastics is particularly needed because these particles may penetrate all kinds of tissues and eventually end up in cells,” he said. “Research should generate data on the occurrence of microplastics and especially nanoplastics in food, their fate in the gastrointestinal tract, and their toxicity.”
Researchers at Lund University, Sweden, have since discovered that nanosized plastic particles can accumulate in fish brains and cause damage. In the UK, the chief medical officer has been keen not to rock the boat and create a food scare based on current evidence. In her 2017 report, “Health Impacts Of All Pollution – What Do We Know?” – Professor Dame Sally Davies dedicated just six paragraphs of the 187-pages to microplastics. “Exposure to microplastics through food is possible, based on studies of seafood; however, it is unknown if this translates into meaningful exposure in the population,” the report reads, whilst human exposure, hazard and therefore consequences of exposure to these microplastics are “largely unquantified”.
This is not just about plastic in the sea, either. In fact, dietary exposure to microplastic particles is likely to be relatively low compared with inhalation of microplastics, according to Food Standards Agency evidence submitted to an Environmental Audit Committee enquiry in 2016. “We need to establish toxic characteristics of microplastics, their behaviour in the body, and what constitutes a safe threshold for exposure when plastics are either ingested or inhaled,” explained Stephanie Wright from King’s College London in an article for the British Medical Journal in September 2017. “We must also relate these data to the different sources, types of plastic, and concentrations we are currently exposed to and, importantly, will be exposed to in the future thanks to the growing global addiction to plastic in all its forms.” Indeed, production of plastic packaging is forecast to double in the next 15 years, to more than 150 million tonnes. Currently, 32% of what is produced leaks into the environment – and whatever toxic effects are discovered in the future, it is going to be impossible to withdraw all those particles floating around in the environment already. Food safety issue or not, it’s certainly an uncomfortable thought.
About David Burrows
David is a freelance writer specialising in sustainability and food/retail. A graduate in agricultural sciences, and a postgraduate in periodical journalism, David is currently freelance writer, editor and researcher for several food/business publications, including Poultry Business, Farmers Guardian and Retail Week.