Over the past 10 years, the medical community has become progressively alarmed by the sheer ubiquity of micro and nanoplastics, tiny plastic particles which have been found in their thousands in food, bottled water, and increasingly in our own bodies.
Recent medical studies have detected the presence of plastic in blood samples, breast milk, placenta tissue, and even people’s lungs.
So when Raffaele Marfella, a surgeon and professor of internal medicine at the University of Campania Luigi Vanvitelli in Naples, and his colleagues conducted a study to examine plaque taken from the arteries of people with cardiovascular disease, they were not surprised to find that half of the samples contained miniature fragments of plastic.
But a closer look at the data indicated a concerning trend – the patients who had accumulated plastic within their arteries all had much more advanced disease. By monitoring them over the next three years, they found that these people were four and a half times more likely to have died or experienced a nonfatal stroke, compared with patients whose samples did not contain any plastic.
Marfella believes that the presence of plastic could have actively accelerated their deteriorating health, through driving inflammation within the arteries. “I can say with reasonable certainty that contamination by micro and nanoplastics causes altered tissue health status,” he says.
It is one of the first studies to have identified a link between plastic deposition and declining human health. But we still need to learn far more about how and why plastic can damage the human body, and most crucially of all, what to do about it.
What are microplastics and where do they come from?
The plastic particles capable of entering the human body are either microplastics, which are less than 5 millimetres wide, or nanoplastics which are less than 1 millimetre wide.
They are thought to originate from the steady degradation of products such as car tyres, mass-produced synthetic clothes and the paint used to coat buildings and roads. However, many scientists believe that single-use plastics such as water bottles, plastic cutlery, food containers, packaging, cotton bud sticks, plastic bags and wet wipes are the biggest culprits.
“Single-use plastic bottles lower the cost of [beverage] production and transportation, but they are one of the major sources of micro and nanoplastics,” says Dick Vethaak, an emeritus professor of water quality and health at VU University Amsterdam and Utrecht University in the Netherlands. “Banning them is an excellent idea, as alternative, safer, and more sustainable materials are already available in the market. As consumers, many of us can make our own decisions to use glass bottles or transport our drinking water in reusable containers.”
It is thought that we inadvertently consume these plastic particles either through inhaling or ingesting them. Earlier this year, a study from researchers at Columbia University in New York identified a quarter of a million nanoplastics in a single litre of bottled water. Another concerning paper found that babies who are fed formula milk prepared in bottles made from propylene are exposed to high levels of microplastics.
What do we know about the impact on human health?
There are more than 10,000 different chemicals present in various plastics, including some which are known carcinogens and others which are capable of disrupting vital hormonal systems.
Because of this, some researchers have begun to question whether plastic accumulation over the course of several decades could be a contributing factor to the rise in cases of colorectal cancer in the under-50s. Last year, a group of bowel cancer and toxicology experts in New Zealand published an article pointing out that emerging research suggests that not all microplastics are excreted from the body, and as a result, some may linger in the colon where they could disrupt the inner mucus layer. This is a key barrier which protects the wall of the colon from bacteria and toxic chemicals and, they suggested, if this barrier becomes damaged by plastic particles, it could lead to cells within the colon becoming far more exposed to potential carcinogens.
While some of this is still speculative, more and more evidence is emerging which shows that plastic is actively harming our gut. In one study from 2021, the levels of microplastics were found to be far higher in the stool samples of people with inflammatory bowel disease, compared with healthy individuals. People with more severe disease had even greater amounts of plastic in their stools.
Matthew Campen, a professor at the University of New Mexico who has studied microplastics, isn’t convinced that the plastics themselves are necessarily harmful, but the problem is more the sheer quantity of them.
“The plastics are relatively safe, it is simply that they appear to be at alarmingly high levels [in the environment] and getting worse,” he says. “We think the main route of entry into the body is through the gut and this is an important issue that needs to be better understood.”
What do we still need to know?
There are many unanswered questions, ranging from whether some forms of plastic are more harmful than others, whether certain sizes or shapes are more likely to inflict damage and what this tells us about where they may have come from.
“Many of the particles found in the human body appear to be less than 2 micrometres in length and 200 nanometres in width, and are often much smaller,” says Campen. “They seem to have a shard-like appearance, like very old, brittle plastics that have sheared apart over many years. We are not yet sure how this affects the biological interactions.”
Vethaak predicts that in the coming years, we will learn even more about how much plastic is present in our bodies, where it goes and what it does.
“Are the doses of plastic particles in our blood and tissues high enough to trigger or mediate [biological] responses that lead to disease?” he says. “This information will be critical for risk assessments, but that data may still be several years away.”
How can we eliminate them or reduce their impact?
Each year, humans produce more than 350 million metric tons of plastic waste, and experts believe that the only solution is to find better and more effective ways of degrading it. In future, certain microbes may help us design more useful waste disposal plants, with various lab experiments suggesting that strains of Rhodococcus ruber and even E. coli could be used to digest common plastics such as polyethylene terephthalate and polyurethane.
Campen feels that governments need to invest more in burning plastics to generate energy to deal with the vast amounts of plastic being stored in landfills around the world, some of which ultimately finds its way into the oceans and the water supply.
“Globally, I think the best solution is to rapidly move to waste-to-energy treatment plants,” he explains. “The daily waste we generate as individuals is the tip of the iceberg compared to the plastics already buried in the landfills. We need to consider active retrieval and incineration of the plastics. It sounds like a bad idea from the standpoint of global warming, but it is ultimately no worse than coal.”
Avoiding plastic entirely is virtually impossible as it is so ubiquitous in our lives, from food packaging to clingfilm, clothing and disposable wipes. Even some tea bags contain a form of plastic called polypropylene to seal them and prevent their contents from spilling out in the box and your mug.
But microplastics experts like Vethaak say that there are a couple of big steps you can take to minimise the amount of plastic you’re ingesting as part of your everyday life. As well as staying clear of bottled water, he particularly emphasises avoiding heating food in tupperware. This is because whenever you microwave something in a plastic container, chemicals from within the plastic leach out into the food, while the intense temperatures actively degrade the plastic at a microscopic level, shedding micro and nanoplastics which ultimately end up in your body.
Vethaak also recommends installing reverse osmosis water filters in your home which are capable of removing some microplastics from tap water.
However because plastic is so entrenched in our world, the scary truth is that there is very little many of us can do to avoid it. As an example, 82 per cent of baby bottles around the world are made from polypropylene, although some brands like Hevea have begun making alternatives from glass and natural rubber.
“Basically, we need to replace plastics with alternative, safer and more sustainable materials and this must be done as soon as possible to minimise health risks,” says Vethaak. “But in the meantime, avoid drinks and foods exposed to plastic as much as you can.”
Source Agencies
