With a view to preparing an international treaty on reducing plastic pollution, the Parliamentary Office for the Evaluation of Scientific and Technological Choices (OPECST) presented the conclusions of a public hearing on its impact on different aspects of human health [1].
Sharp increase in global plastics production
While the last round of negotiations on the future international treaty aimed at eliminating plastic pollution was held (from November 25 to 1is December in South Korea), “we wanted to hear from the main French and world experts on the impact of plastics on human health”, explains the Les Démocrates MP Philippe Bolorapporteur for the public mission on the impacts of plastics on human health.
The hearing first made it possible to highlight a sharp increase in the production of plastics. “It has doubled over the last 20 years and is expected to exceed 500 million tonnes in 2024, which represents around 60 kg per earthling. According to OECD projections, plastic production is expected to reach 750 million tonnes in 2040 and exceed one billion tonnes before 2050,” he explains.
Very little recycled plastic waste
Of these plastics, 32% are used for packaging. “The production of plastics therefore remains mainly intended for single use,” he emphasizes. The plastic waste produced also follows this growth curve: it is expected to increase from 360 million tonnes in 2020 to 617 million in 2040. However, very little waste is actually recycled, even in the most advanced countries in terms of collection and sorting. and treatment.
Thus, in France in 2018, of the 3.6 million tonnes of plastic waste produced, only 0.6 million tonnes were actually recycled, or 17%. Globally, less than 10% of plastic waste is recycled. In 2020, plastic waste ending up in the environment represented 81 million tonnes, or 22% of the total. “Beyond waste, this leads to pollution of microplastics and nanoplastics, resulting from their fragmentation. All environments are affected: seas, rivers, soils, air and even living organisms,” warns the MP.
Methodological difficulties
However, measuring the impact of these plastics on health faces methodological difficulties linked to the wide variety of composition, size and shape of plastics. Nevertheless, Afnor has carried out standardization work which has made it possible to establish a standard for characterizing microplastics in water serving as a reference at the international level. “It is also very difficult to know what we are ingesting. A study carried out in 2019 estimated that the absorption of plastics by humans was 5 g per week, the equivalent of a credit card [2]. Since then, other studies have revised these data downwards, without reaching a consensus,” explains Philippe Bolo.
A recent study, carried out in 109 countries both industrialized and developing, showed high exposure, estimated at 500 mg per day, in South-East Asian countries mainly due to the consumption of seafood. [3].
Nanoplastics are even more difficult to quantify, due to their small size. A 2023 bibliographic review highlighted the presence of nanoplastics in certain foods such as tea or rice.
A study (to be confirmed) concluded that plastic water bottles contain 250,000 particles per liter, 90% of which are nanoplastics [4]. However, these particles can cross the intestinal barrier or the epithelium to enter the blood circulation and reach numerous organs (kidney, testicles, placenta, brain, etc.). (Read Water bottles: researchers reveal the previously unknown world of nanoplastics)
Changes in the microbiota
Furthermore, microplastics accumulate in the organs. Thus, the amount of plastic in the lung increases with age, suggesting that particles may persist in the body without being eliminated. The health consequences are still poorly understood, but it has been shown that exposure to plastics seems to lead to changes in the composition of the intestinal microbiota. Bacteria appear in both adults and children such as pathobionts (subtypes of commensal bacteria with deleterious potential, RDLR), which can contribute to dysbiosis of the intestinal microbiota.
Furthermore, a reduction in butyrate, a very beneficial short-chain fatty acid (SCFA), has been observed in children. Inhaled nanoplastics can disrupt the mucociliary clearance mechanisms of the respiratory system.
The toxicity of inhaled plastic particles was demonstrated in the 1970s among workers in the flocking industry. Some of them developed alterations in lung function, shortness of breath, inflammation, fibrosis and, in some cases, even lung cancer. The same symptoms have been observed among workers in the textile and PVC industries.
Furthermore, a study recently published in the New England Journal of Medicine measured the quantity of microplastics collected from the carotid plaque in more than 300 patients who underwent carotid surgery [5]. It highlighted a 4.53 higher risk of myocardial infarction, and potentially more strokes, or even death, in people who had the highest levels of micro- and nanoplastics.
A high health impact
The dangerousness of plastics is also linked to the chemical substances they contain. A general scientific review examined the impact on health of three chemical substances used almost exclusively in plastics [6] : polybrominated diphenyl ethers (PBDE), used as flame retardants in textile or electronic products; bisphenol A (BPA), used to coat cans and cans; phthalates and in particular DEHP – bis(2-ethylhexyl) phthalate used in particular to make plastic more flexible.
It highlighted solid epidemiological evidence establishing links between fetal exposure to PBDEs during pregnancy and low birth weight, delayed or impaired cognitive development in children or even loss of intelligence quotient. (IQ). Statistically significant evidence of endocrine disruption linked to the functioning of the thyroid hormonal system in adults has also been demonstrated.
The damage is already there, we must act to preserve human health
Philippe Bolo
BPA is linked to genital malformations in newborn girls exposed to BPA in the womb, with type 2 diabetes in adults and insulin resistance, and with polycystic ovarian syndrome. in women. Exposure to BPA also increases the risk of obesity and hypertension in children and adults as well as the risk of cardiovascular disease in adults.
Finally, the general review establishes links between exposure to DEHP and miscarriages, genital malformations in newborn boys, delayed or impaired cognitive development in children, loss of IQ, delayed psychomotor development, early puberty in young girls and endometriosis in young women.
Exposure to DEHP also has multiple effects on cardiometabolic health, including insulin resistance, obesity and increased blood pressure.
The economic costs linked to the health impact of these three substances have been estimated at $675 billion in the United States. [7].
For MP Philippe Bolo, the solution to this plastic pollution is necessarily international. “We must obtain an ambitious and legally binding treaty to reduce the production of plastics,” he believes. OPSCT thus formulated 9 recommendations intended for the treaty negotiators. “The damage is already there, we must act to preserve human health,” he concludes.
