Plastics have been polluting the planet since the mid-20th century, affecting both natural and urban ecosystems. As a result, global pollution ranks second to climate change as a serious environmental health threat.
icroplastics – solid particles and fibres measuring 5mm or less – occur due to weathering and degradation of commonly used plastic objects, such as toys, tools, furniture, clothes and paint. They are also added to cosmetics and cleaning products that end up in the environment.
Researchers in Trinity College became leaders in the field in the area when they found that plastic food containers shed huge numbers of microplastics into hot water.
Dunzhu Li and his colleagues reported in October 2020 that kettles and baby bottles shed microplastics. If parents prepare baby formula by shaking it in hot water inside a plastic bottle, their baby may end up swallowing more than one million microplastic particles a day.
All of this means we are constantly swallowing and inhaling microplastics.
Recent research in the UK has identified microplastic pollution in human blood, and lodging in organs, including in lung tissue.
Half of the samples contained PET plastic, commonly used in drinks bottles, textile fibres and mobile phones. A third contained polystyrene, used for packaging food and a quarter polyethylene – used for plastic bags.
The most stringent and compulsory measures that can be seen as fit are justified
Microplastics have been found in more than 90pc of Ireland’s protected marine environments. Researchers at NUI Galway’s Earth and Ocean Sciences Department in 2021 found that more of the material was captured in finer-grained sediment such as mudflats. The multitude of clear fibres found suggests they come from grey water sources such as sinks and baths but primarily from washing machines.
“Ireland is the highest producer of plastic waste per person in the EU and the fourth worst in recycling rate,” said lead author, Dr Liam Morrison, citing Eurostat data.
The study is important in helping understand the possibility of microplastics being consumed by sea life which in turn can be consumed by humans.
“For the past 100 years, plastic has been going into the sea. Some scientists estimate that by 2050 there will be more plastic in the sea than fish,” Dr Morrison added. “We have to start changing human behaviour.”
Why are microplastics bad?
Researchers have been worried about potential harms of microplastics for two decades, although most research has focused on risks to marine life.
More than 100 laboratory studies have exposed animals, mostly aquatic organisms, to microplastics.
Recent research has identified microplastic pollution in human blood, and lodging in organs, including in lung tissue
Findings – that exposure might lead some organisms to reproduce less effectively or suffer physical damage – are hard to interpret because microplastics span many shapes, sizes, and chemical composition.
The tiniest specks – called nanoplastics – smaller than one micrometre – worry researchers most of all. Some might be able to enter cells, potentially disrupting cellular activity.
One thing is clear: the problem will only grow.
Even if all plastics were stopped tomorrow, existing plastics in landfills and the environment – estimated at around five billion tonnes – would continue degrading into tiny fragments that are impossible to clean up.
Albert Koelmans, an environmental scientist at Wageningen University in the Netherlands, calls this a “plastic time bomb”.
“If you ask me about risks, I am not frightened today,” he says in a review in Nature in 2021. “But I am a bit concerned about the future.”
Researchers have several theories about how the plastic specks may be harmful.
If they are small enough to enter cells of tissues, they might irritate just by being a foreign presence – as with the long, thin fibres of asbestos, which can inflame lung tissue and lead to cancer.
Another theory is that microplastics in the environment might attract chemical pollutants and then deliver them into animals that eat the contaminated specks. Researchers are unsure whether this is a significant problem.
Perhaps the simplest mode of harm when it comes to sea organisms is that marine life swallow plastic specks of no nutritional value and don’t eat enough to survive.
Zooplankton, among the smallest marine organisms, reproduce less successfully in the presence of microplastics – the eggs are smaller and less likely to hatch.
For the moment, researchers think that levels of microplastics and nanoplastics in the environment are too low to affect human health. But their numbers will rise.
“The far biggest gains would come from cutting out plastic that is used only once and discarded. There’s no point producing things that last for 500 years and then using them for 20 minutes,” said Professor Tamara Galloway, an exotoxicologist at the University of Exeter. “It’s a completely unsustainable way of being.”
The multitude of clear fibres found suggest they come from grey water sources such as sinks and baths but primarily from washing machines
The multitude of clear fibres found suggest they come from grey water sources such as sinks and baths but primarily from washing machines
A recent EU position paper published in June, considers how EU legislation can tackle microplastic pollution.
The evidence available on the persistence, harmfulness, omnipresence, and constant increase of microplastic pollution is sufficient to justify the adoption of “the most stringent and compulsory measures that can be seen as fit”.
This means that voluntary agreements should not be considered. Monitoring and enforcement mechanisms should reflect this obligation.
The paper lays out a range of proposals, including banning intentionally added microplastics (glitter, sequins, microbeads) in consumer products, banning the use of granules or pellets from school playgrounds or sports pitches, mandatory measures to scale up the re-use and repair of products and incentivising the re-use of clothing.
Compulsory environmental risk assessment for all products containing plastics and measures to mitigate microplastic emissions is recommended.
Monitoring microplastic pollution in sediment, water, soil and the atmosphere, as well as the monitoring of litter and other projects associated with plastic pollution is suggested.
Other measures for consideration include waste management systems, extended producer and corporate social responsibility, use of capturing and filtering technologies, mandatory best practice handling, the setting up of an open access database listing all additives used in plastic and recycled plastic, and mandatory labelling and information for consumers.
The days of single-use plastic are numbered and none too soon.
Plastic forks, plates and coffee cups are all but gone. A bigger challenge is the cheap clothing that is designed to be worn a handful of times before being discarded.
With winter approaching, temperatures dropping and the price of fuel skyrocketing, now is the time for plastic-free fibres – warm coats, woollen jumpers, thick socks.
The profit-driven global throwaway market has had its own way for too long.
The days of discretionary waste are gone.
Clothes need to last a lifetime. Electrical goods need to be repaired and reparable, and all plastic products that pollute and degrade for several centuries need to be quantified in terms of the amount of value they provide before they are discarded on the landfill or seep into the ocean.
Dr Catherine Conlon is a public health doctor in Cork and former director of human health and nutrition at Safefood. All views are the author’s own
