Twenty years ago a team of British scientists raised the alarm about an underappreciated problem at the time: the breakdown of plastic debris into small, even microscopic, fragments. While many previous reports have documented the build-up of plastic bottles and bags in the natural environment, much less attention has been paid to what the scientists have called “microplastics”.
Due to “the rapid increase in plastic production, the longevity of plastic and the disposable nature of plastic items,” the researchers concluded that there is “significant potential” for microplastic pollution to become a major problem for the environment and human health. to become
Turns out they were right.
Over the past two decades, the rate of plastic production has increased approx doubledto more than 400 million metric tons per year, about the weight of 1,200 Empire State Buildings. In the same period, microplastics – defined as particles with a diameter of less than 5 micrometres, about the width of a human hair – exploded into the public consciousness, riding a wave of research into the particles’ occurrence across ecosystems and in people gone ‘bodies. Since that 2004 paper, one of the first to use the term “microplastics,” microscopic plastic fragments have been found everywhere from deep sea sediments to the summit of Mount Everestas well as in human blood, breast milk, colons, kidneys, livers, lungs, placentasand other body parts.
Many of these findings are synthesized in a review paper published this week in the journal Science. The paper considers what we have learned from thousands of research papers on microplastics – including where they come from, where they end up and how they affect organisms – and assesses regulatory options to deal with the problem.
Research on the topic “has taken off a bit,” said Richard Thompson, a professor of marine biology at the University of Plymouth in the United Kingdom who was lead author of the 20-year-old paper and the new one published Thursday. “It’s pretty clear now that this stuff is everywhere,” he added, and that unless something changes, humanity will eventually reach a point of “wide-scale” and “irreversible” damage to the environment.
One thing that has become much clearer since the early 2000s is the sheer scale of microplastic pollution. While Thompson’s 2004 paper documented small fragments of acrylic, nylon and polyester in coastal environments in the UK, further investigation has shown that pollution is global. By now, microplastics have been found in virtually every ecosystem researchers have looked at, including in grounds, lakesand riversand on remote mountains. One alarming study from 2020 found that microplastics in rainwaterwhile others have shown it the particles are ubiquitous in the indoor air we breathe. Earlier this year, environmental consulting firm Earth Action estimated this nearly 13 million metric tons of microplastics enter the oceans and terrestrial environment annually.
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Where did all this microplastic come from? Early on, scientists assumed they were generated by larger pieces of plastic debris breaking down – and indeed, this is the main source of microplastics. But much more has been identified. Paint, for example, contains plastic polymers and can contribute as much as 1.9 million metric tons of microplastics annually to the marine environment. Some of the other major sources of microplastics include rubber tireswhich sheds microplastics as they rub against the road, and synthetic textileswhich release microfibers when worn and washed. An unknown amount of microplastic pollution comes from plastic-derived fishing nets and gear, which make up a large fraction of plastic in the ocean more generally.
One reason scientists have found microplastics so far is because more are looking for them than ever before. But those scientists also have better technologies at their disposal. A type of imaging called pyrolysis-gas chromatography-mass spectroscopyfor example, recently made it easier for researchers to identify small, dark microplastics released by the erosion of rubber tires. Other methods have made it possible to more precisely count the number of microplastics in a given sample, and to sort them by size and polymer—all of which can yield clues about their toxicity.
More researchers and better technology have also led to the detection of microplastics in living organisms. Over the past 20 years, scientists have identified microplastics in more than 1,300 aquatic and terrestrial speciesand throughout the human body. High-profile headlines in the past few months have highlighted the presence of the particles human testicles and penisesand this February scientists at the University of New Mexico found microplastics in each placenta out of 62 they tested. Scientists do not yet have a complete picture of exactly how this pollution affects human health, but laboratory studies have linked microplastics to cell inflammation and the spread of cancer. Some epidemiological evidence suggests that they are a risk factor for heart disease.
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These findings help explain why microplastics have so quickly risen to the top of many average people’s priority lists. In Germany, for example, consumers in a 2023 survey said they are more concerned about microplastics in food than any other health topic, including antibiotic resistance and pesticide residues on food. One more recent survey showed that more than 90 percent of American voters are also “somewhat” or “very” concerned about microplastics in the human body. Many jurisdictions seek to hold plastic manufacturers responsible for the pollution they have caused, and at least two lawsuits against the plastics industry—one brought by the New York Attorney General’s Office and the other brought by the City of Baltimore — specifically mentions the distribution and health risks of microplastics.
Industry groups acknowledge that people are exposed to microplastics, but deny that there is any evidence that they can harm human health or the environment. On his side websiteThe Plastics Industry Association says the industry is “supporting more and better research on microplastics” and highlights its investments in pollution prevention and recycling infrastructure. “Everyone agrees on one thing,” says the trade group: “Plastic, big or small, does not belong in our waterways.”
On that narrow point, Thompson agrees. He believes there is already enough evidence of microplastic’s harm that scientists should concentrate on ways to prevent microplastics from entering the environment in the first place. Various interventions have already been taken — a 2020 French lawfor example, now requires new washing machines to come with microfiber filters, and the European Union is phasing out glitter and other microplastics from products such as shampoo and lotion. But Thompson’s paper highlights the need for multidisciplinary approaches that take into account insights from a variety of fields, including economics and behavioral science. Initiatives to replace single-use plastics with reusable alternativesfor example, can play a big role in reducing the generation of microplastics – but they will only work if they are cheap and convenient enough for consumers to accept them.
“Making something work is not just about a chemistry experiment in a lab,” Thompson said. “It’s going to take changes in social norms, the economy, society, legal frameworks.”
At the broadest level, Thompson, other scientistsand environmental advocates support measures to limit overall plastic production and ban the most problematic categories of plastic, both of which would indirectly reduce the generation of microplastics. These solutions are currently being discussed as part of a high profile United Nations treaty to end plastic pollution. Jen Fela, vice president of programs and communications for the nonprofit Plastic Pollution Coalition, described the treaty as “the best chance we have” to address the plastic pollution crisis.
“Solutions exist,” she told Grist. “The only way to stop plastic pollution is to significantly reduce plastic production.” The fifth and final round of negotiations on the treaty is scheduled to take place this November and December in Busan, South Korea.
