Health Impacts of Micro- and Nanoplastics

In preparation for a future international treaty aimed at reducing plastic pollution, the French Parliamentary Office for the Evaluation of Scientific and Technological Choices presented the conclusions of a public hearing on the impact of plastics on various aspects of human health.

Increased Global Plastic Production

Philippe Bolo, a member of the French Democratic Party and the rapporteur for the public mission on the health impacts of plastics, spoke about the latest round of treaty negotiations, held from November 25 to December 1 in South Korea, attended by leading French and global experts about the impact of plastics on human health.

The hearing highlighted a sharp increase in plastic production. “It has doubled in the last 20 years and is expected to exceed 500 million tons in 2024,” Bolo said. This is about 60 kg per person. According to projections from the Organization for Economic Co-operation and Development, on its current trajectory, plastic production will reach 750 million tons by 2040 and surpass 1 billion tons before 2050, he said.

Minimal Plastic Waste Recycling

Around one third (32%) of plastics are used for packaging. “Therefore, most plastic production is still intended for single-use purposes,” he said. Plastic waste follows a similar growth trajectory, with volumes expected to rise from 360 million tons in 2020 to 617 million tons by 2040 unless action is taken. Very little of this waste is recycled, even in the most countries that are most advanced in terms of collection, sorting, and processing.

In France, for example, in 2018, only 0.6 million tons of the 3.6 million tons of plastic waste produced was truly recycled. This is less than one fifth (17%). Globally, less than 10% of plastic waste is recycled. In 2020, plastic waste that ended up in the environment represented 81 million tons, or 22% of the total. “Beyond waste, this leads to pollution by microplastics and nanoplastics, resulting from their fragmentation. All environments are affected: Seas, rivers, soils, air, and even living organisms,” Bolo said.

Methodological Challenges

However, measuring the impact of plastics on health faces methodological difficulties due to the wide variety of composition, size, and shape of plastics. Nevertheless, the French Standardization Association ( Association Française de Normalisation) has conducted work to establish a characterization standard for microplastics in water, which serves as an international reference.

“It is also very difficult to know what we are ingesting,” Bolo said. “A study conducted in 2019 estimated that the average human absorbs 5 grams of plastics per week, the equivalent of a credit card.” Since then, other studies have revised this estimate downward, but no consensus has been reached.

A recent study across 109 countries, both industrialized and developing, found significant exposure, estimated at 500 mg/d, particularly in Southeast Asian countries, where it was due mainly to seafood consumption.

A study concluded that plastic water bottles contain 240,000 particles per liter, 90% of which are nanoplastics. These nanoparticles can pass through the intestinal barrier to enter the bloodstream and reach several organs including the heart, brain, and placenta, as well as the fetus.

Changes to the Microbiome

Microplastics also accumulate in organs. Thus, the amount of plastic in the lungs increases with age, suggesting that particles may persist in the body without being eliminated. The health consequences of this are still poorly understood, but exposure to plastics appears to cause changes in the composition of the intestinal microbiota. Pathobionts (commensal bacteria with harmful potential) have been found in both adults and children, which could contribute to dysbiosis of the gut microbiome. Furthermore, a decrease in butyrate, a short-chain fatty acid beneficial to health, has been observed in children’s intestines.

Inhaled nanoplastics may disrupt the mucociliary clearance mechanisms of the respiratory system. The toxicity of inhaled plastic particles was demonstrated as early as the 1970s among workers in the flocking industry. Some developed lung function impairments, shortness of breath, inflammation, fibrosis, and even lung cancer. Similar symptoms have been observed in workers in the textile and polyvinyl chloride industries.

A study published recently in TheNew England Journal of Medicine measured the amount of microplastics collected from carotid plaque of more than 300 patients who had undergone carotid endarterectomy for asymptomatic carotid artery disease. It found a 4.53 times higher risk for the primary endpoint, a composite of myocardial infarction, stroke, and all-cause mortality, among individuals with microplastics and nanoplastics in plaque compared with those without.

Health Affects High

The danger of plastics is also directly linked to the chemical substances they contain. A general scientific review looked at the health impacts of three chemicals used almost exclusively in plastics: Polybromodiphenyl ethers (PBDEs), used as flame retardants in textiles or electronics; bisphenol A (BPA), used in the lining of cans and bottles; and phthalates, particularly diethylhexyl phthalate (DEHP), used to make plastics more flexible.

The review highlighted strong epidemiological evidence linking fetal exposure to PBDEs during pregnancy to low birth weight and later exposure to delayed or impaired cognitive development in children and even a loss of IQ. Statistically significant evidence of disruption of thyroid function in adults was also found.

BPA is linked to genital malformations in female newborns exposed to BPA in utero, type 2 diabetes in adults, insulin resistance, and polycystic ovary syndrome in women. BPA exposure also increases the risk for obesity and hypertension in both children and adults, as well as the risk for cardiovascular disease in adults.

Finally, the review established links between exposure to DEHP and miscarriages, genital malformations in male newborns, delayed or impaired cognitive development in children, loss of IQ, delayed psychomotor development, early puberty in young girls, and endometriosis in young women. DEHP exposure also has multiple effects on cardiometabolic health, including insulin resistance, obesity, and elevated blood pressure.

The economic costs associated with the health impacts of these three substances have been estimated at $675 billion in the United States.

Bolo said that the solution to this plastic pollution is necessarily international. “We need an ambitious and legally binding treaty to reduce plastic production,” he said. “The damage is already done; we need to act to protect human health,” he concluded. The parliamentary office has made nine recommendations to the treaty negotiators.

This story was translated fromMedscape’s French edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.