Finding microplastics in the parts of the human body is not new: scientists have discovered tiny waste in human blood, lungs, brains, hearts and testicles.
But a new study, Published Monday in the journal Nature Medicine, shows a locking relationship between the quantity of plastic found in the tissues harvested from human corpses and the quantity produced by the plastic industry.
As the production of global plastic has increased in the past 20 years, the same is true for the concentration of these derivative polymers derived from fossil fuel in samples of human tissue.
The results are “quite striking,” said Phil Landrigan, director of the global public health program and the common good at Boston College, who was not affiliated with research.
The study also showed a correlation concerning patients who had received a dementia diagnosis before their death and the amount of plastic particles found in their brain – adding to a Correction of growing research indicating that the presence of these particles in the human body can potentially cause damage.
The study was published by a team of researchers from the University of New Mexico, Oklahoma State University, Duke University and Universidad del Valle, Colombia.
The team acquired samples of brain, liver and renal tissue of patients who had undergone autopsies between 2016 and 2024 at the University of New Mexico.
To determine both the concentration and types of plastic in the samples, the team visually inspected the samples and applied the chromatography of pyrolysis -Gaz – Mass spectrometry – a technique which allowed them to analyze the chemical composition of the fabric.
They found that the particle concentrations in the kidney and liver samples were comparable, with an average of 433 micrograms of microplastic per gram of fabric in the liver samples and 404 micrograms per gram of kidney samples.
But the levels observed in brain samples – all taken from the frontal lobe – have overshadowed these figures and showed a jump over time. In the samples they collected from deceased people in 2016, they found average concentrations of 3,345 micrograms / gram. In the 2024 cohort, the average was 4,917.
“I would never have imagined that it was so high,” said Matthew Campen, professor of pharmaceutical sciences at the University of New Mexico. “I certainly do not feel comfortable with so much plastic in my brain, and I don't need to wait about 30 years more to discover what is happening if the quadrupted concentrations.”
The concentrations of microplastics that the researchers found were independent of the biological age of the deceased – regardless of that the person was young or old at his death. What was counting is the year they died – the more recent death, the more plastic accumulated in the body.
Intrigued by this increase in plastic concentration over time, the researchers have obtained more brain tissue samples. This time, they examined the brains of people who died between 1997 and 2013. They made sure that the corpses were also older than those they had already examined – but could not control geography. The second cohort came from people who died on the east coast.
Again, the researchers have found “considerably growing trends for total plastics” over time in this second group of samples.
Polyethylene – a plastic polymer used to do things such as plastic bags, milk jugs, shampoo bottles, etc. – was the most current microplastic in the brain. It represented 75% of the plastic bursts observed in the brain tissue samples. But the researchers also detected polypropylene (plastic used to make yogurt cups and rigid take-out food containers), polyvinylchloride (which is used in most water pipes) and styrene-fog rubber (found in certain pneumatic tires, shoe soles, brake pads and electric insulation).
The concentration of all these plastics increased from 2016 to 2024, regardless of the biological age of the corpse.
They also noted that the brain tissues collected by patients who had been diagnosed with dementia had higher concentrations of microplastics than those who had not done so. Although it is a worrying observation, they noted that their sample size was small and that the characteristics of dementia include atrophy of the brain tissue, the integrity of the altered blood barrier and the mediocre cerebral clearance mechanisms – which could themselves lead to microplastic accumulation.
Therefore, they could not pretend to be causal – just a correlation.
Landrigan said that work strengthens our knowledge “that we are all exposed, that these things really penetrate into our body, in people of all ages” and that it “seems to worsen over time”.
He said it adds to the urgency of a World Treaty of Plastics – To cap the plastic production – and which reached a dead end in the last series of negotiations in South Korea, in 2024. He declared that the negotiators planned to reconstruct themselves later this year.
According to Landrigan, we do not know how the United States, under President Trump, would approach the treaty. If Trump follows the advice of supporters of fossil fuels in his administration, it is likely that the United States will vote for the agreement – or do not even arise.
But if the element Robert F. Kennedy Jr. obtains a seat at the table, the United States is a joker, said Landrigan. Kennedy was openly critical with regard to the Biden administration for not having done enough to put the flow of microplastics in the environment, and he wrote a detailed plan This prohibits most of dangerous chemicals, would reform the recycling infrastructure and limit the production of plastics.
Landrigan said he had known Kennedy for decades and that he would sit with him with him to present this research and the growing number of studies showing the damage that these particles – and the chemicals they wear – cause in the human body.
“I am a pediatrician of the American Academy of Pediatrics, and we have always taken the position that the Academy will do what it has to do to protect the health of children. We will always defend children. So if there is an opening there for a conversation with Bobby, why not? ” He said.
