Ramping up plastic recycling might seem like a logical way to transform waste into a resource. But recent studies suggest that recycling plastic poses its own environmental and health risks, including the high levels of microplastics and harmful toxins produced by the recycling process that can be dangerous for people, animals and the environment.
Microplastics
“We found pretty scary amounts, to be honest,” said plastics scientist Erina Brown, lead author of a research paper into the microplastic run-off produced by recycling centers, published in May 2023.
The UK recycling centre at which Brown based her studies used large amounts of water (common practice in the recycling industry) to sort, shred and separate plastics before they were compounded and turned into pellets for resale.
Her research tested the rate of microplastics – plastic particles up to 5mm in size – released into the water through the process.
“There were 75 billion particles per metre cubed in the wash water,” she said. “About 6 percent of all the plastics that were coming into the facility were then being released into the water as microplastics, even with the filtration [system].”
Scientists are still researching the possible risks of microplastics on human health. They are thought to carry disease-causing organisms that act as a vector for diseases in the environment – where many plastic particles produced by recycling are likely to end up.
Water used in recycling centers around the world often passes through sewage treatment facilities, which “are just not designed to filter this size of microplastic”, Brown says.
Microplastics caught in sewage sludge are often inadvertently applied to fields as fertilizer, while those that remain in the treated water enter local streams and end up even farther afield – a study released in March showed microplastics from European rivers had spread to Arctic seas.
More than two-thirds of UN member states agreed in March last year to develop a legally binding agreement on plastic pollution by 2024, and the second round of meetings to draw up the treaty began on Monday in Paris and will run through Friday.
UN Environment Programme (UNEP), which is hosting the talks, released a roadmap to reduce plastic waste by 80 percent by 2040.
But some environmental groups have said the three key areas of action outlined – reusing, recycling and reorientation towards alternative materials – are a concession to the global plastics and petrochemicals industry as they downplay the need to reduce use of plastic altogether.
Recycled plastics pose greater risk
Microplastic release is not the only flaw in the system. Recycling plastics means working with unregulated toxic chemicals.
Plastics are made with as many as 13,000 chemicals, according to a UN report this month, and 3,200 of those have “hazardous properties” that could affect human health and the environment. Many more have never been assessed and may also be toxic, according to a report from Greenpeace released last week.
In addition, “only a very, very small portion of those chemicals are regulated globally”, said Therese Karlsson, science and technical adviser at the International Pollutants Elimination Network (IPEN). “Since there's no transparency [in the market], there's no way for people to know which plastics contain toxic chemicals and which don't.”
The risk these chemicals pose increases among recycled plastics, as products with unknown compositions are heated and mixed together.
“The outcome is a completely unknown product that is reintroduced onto the market,” Karlsson said.
Greenpeace’s report also detailed increased health risks for recycling centre workers exposed to toxic chemicals, including long-term health conditions such as cancer and harm to reproductive systems.
It also found higher levels of toxic chemicals in recycled plastic than in their virgin counterparts, including kitchen utensils, children’s toys and food packaging.
The spread does not end there. “We've done studies on eggs that are close to places that recycle plastics and found that these chemicals are making their way into the food chain,” Karlsson said.
“Plastics can act as carriers of these chemicals even to really remote places.”
Soaring plastic production
The share of plastic waste that is recycled globally is expected to rise to 17 percent by 2060, according to figures from the OECD. But recycling more will not address a major issue: after being recycled once or twice, most plastics come to a dead end.
“There’s a myth with plastic recycling that if the quality is good enough the plastics can be recycled back into plastic bottles,” says Natalie Fée, the founder of City to Sea, a UK-based environmental charity.
“But as it goes through the system, it becomes lower- and lower-grade plastic. It's down-cycled into things like drain pipes or sometimes fleece clothing. But those items can't be recycled afterwards.”
It is therefore difficult to make the case that recycled plastic is a sustainable material, said Graham Forbes, Global Plastics Campaign leader at Greenpeace USA, in a statement this week.
“Plastics have no place in a circular economy. It’s clear that the only real solution to ending plastic pollution is to massively reduce plastic production.”
And it is impossible for increased recycling to keep pace with the amount of plastic waste being produced – which is expected to almost triple by 2060.
“There's no way that we can recycle our way out of this,” added Karlsson. “Not as it works today. Because today, plastic recycling is not working.”
This is something she hopes the treaty under discussion in Paris this week will address.
Coming into the talks in Paris, a 55-nation coalition called for restrictions on some hazardous chemicals and bans on problematic plastics products that are hard to recycle and often end up in nature.
Karlsson is attending the talks, and she sees reason for hope. “The plastics treaty is an incredible opportunity to protect human health and the environment from plastic pollution. Doing that would mean phasing out toxic chemicals from plastics, ensuring transparency across the plastic life cycle and also decreasing plastic production.”
