Researchers from a laboratory in New Mexico estimate that in the human brain There may be the equivalent of five bottle plugs. Now they try to find out their effects.
In a basement laboratory from the University of New Mexico, Marcus Garcia search in a container full of plastic waste. Collected bottles, pieces of fishing network, a toothbrush, a glass with a character from Pokémon and a Gi Joe.
“Yes!” He exclaimed, raising a discarded pipette tip. “I found it.”
Garcia, postdoctoral fellow in Pharmaceutical Sciences, discovered the Pipeta tip last summer with some colleagues in a remote Hawaii beach. He was miraculously intact, although he had probably degraded for years by the sun, ozone and the ocean. How tragic, he thought. It was an object that he and thousands of scientists used daily. And there it was, stranded on a beach along with hundreds of kilos of other plastic waste that were now cleaning and collecting for the investigation.
Garcia is part of an avant -garde laboratory, directed by the toxicologist Matthew Camlan, who studies how the tiny particles known as microplastics. The most recent work of researchers, published in February in Nature Medicine, generated a series of alarmed headlines and a stir in the scientific community: they discovered that 2024 human brain samples had almost 50 percent more microplastics than the 2016 brain samples.
“This material is increasing exponentially in our world,” said Camn. As they accumulate in the environment, they also accumulate in us.
Other findings of the researchers also caused a generalized concern. In the study, the brains of people with dementia had many more microplastics than people’s brains without it. In publications last year, researchers showed that microplastics were present in human testicles and placentas. Other scientists have also documented them in the blood, semen, breast milk and even in the first deposits of a baby.
Also in February, the Champion laboratory published a preliminary investigation, together with colleagues from Baylor College of Medicine and Texas Children’s Hospital, which showed that the placentas of the baby born prematurely contained more microplastics than those of the babies born to term, despite having had less time to accumulate those particles.
But despite all the places where they found microplastics and all the concern for health risks, there were many things that researchers still did not understand. The first thing toxicologists learn is that “the dose makes the poison”: any substance, even water, can be poisonous at a sufficiently high dose. But Camlan and Garcia had no idea how many microplastics needed to begin to cause health problems. And with so many plastics in our world, was it our food, our clothes, our air or other sources completely those that raised the greatest threat?
To start answering these questions, they turned to the bodies.
In plastic hunting
At the end of the hall where Garcia was searching, a closet from the main laboratory of the team contained brain samples, hígados, kidneys, arteries and sexual organs.
Garcia opened a bottle with the label “dB”-for the acronym in English of “Dementia Brains” which means brains with dementia-that gave off a family smell for those who have spent time in an anatomy laboratory: formaldehyde. With some tweezers, it started a piece of brain tissue and placed it on a crystal oil plate. It seemed a piece of tofu, with a thick gray matter that surrounded a narrow white strip.
In their article, the researchers reported that the average concentration of microplastics in 24 human brains of 2024 was almost 5000 micrograms per gram, although there is enough uncertainty in that estimate due to the methods used to calculate it. That is equivalent to about seven grams of plastic by brain, as well as what composes a disposable spoon, said Camlan, or about five plugs of water bottles. The brains of people with dementia had more, although the researchers pointed out that this could be due to the fact that these brains have a more porous hematocephalic barrier and are less capable of eliminating toxins.
It is still not clear what effect this amount of plastic has in human health, but it is enough to cause alarm. “I don’t think I talked to any person who has said: ‘Fantastic! I love knowing that there is all that plastic in my brain,” said Caman.
His group is now studying the tissue of cross -sectional cuts of a single brain to find out if certain regions have higher concentrations of microplastics and if that could be related to problems such as Parkinson Parkinson or memory loss. Ideally, to compare, he would like to study a brain before the 1970s or 1960s, when plastics became omnipresent. “Imagine the classic old museum with a brain floating in a bottle,” he said. “I really need one of those.”
The experiments are expensive and require a lot of time. It is not easy to get brain samples. The machines that analyze the plastics cost about $ 150,000 each. (Together with the oldest, a research assistant had placed a candle with an image of Jesus and the words “I trust you”, hoping that the machine would continue to run without problems. Of course, they don’t really light it).
But these studies have allowed Camlan to draw certain conclusions that no one else has drawn. They led him to believe that the microplastics of our body are much smaller than other scientists had described, which would explain how they cross the barriers of our body and reach our organs. He confirmed that suspicion using a high resolution microscope: this showed similar fragments in its shape to broken glass or ceramic pieces of no more than 200 nanometers in length-a 400 times less than the width of a hair-and so fine that they were translucent. In previous studies microscopes had been used that could only see up to 25 times that size.
For Camlan, documenting such small particles could turn our understanding of the amount of plastic in us, how it gets there, where you could go and what damage could cause.
Decades ago
Researchers cannot say with certainty how these plastics get to our body or where they come from, but they have some clues. They know that plastic waste ends up on the ground, water, air and even rain, said Christy Tyler, a professor of environmental sciences at the Rochester Institute of Technology, who studies microplastics in aquatic ecosystems. It can be incorporated into plants and concentrate as the food chain ascends. The plastic is in our clothes, our carpets, our armchairs and our food storage containers: “Actually, it is everywhere,” Tyler said.
The characteristics of the plastics found by the champion team in the human fabric suggest that they come mainly from waste produced many years ago and eroded over time. The researchers found a significant amount of polyethylene, for example, the dominant type of plastic produced in the 1960s, but less of the plastic used in the water bottles, which took off in the 1990s.
Since plastic production has doubled every 10 or 15 years, although we would stop manufacturing it today, both plastic is already used that more and more residues would accumulate in the environment and, potentially, in our bodies during the next decades.
Campe suspects that the main way in which these plastics enter our body is when we eat them, much after they have been discarded and have begun to break down. He is less concerned with fresh plastics, such as those that come from the cutting boards and water bottles while we use them, because those particles are much larger and new than he has measured. And research suggests that the body eliminates some larger microplastics.
Camlan acknowledged that his opinion on fresh plastics was “unconventional”, and other scientists say it is worth taking measures to reduce your exposure. It is clear that microplastics can leak of water bottles, microwave food containers and synthetic clothing, and investigations carried out in animal studies suggest that these particles could be harmful, said Tracey Woodruff, director of the Reproductive Health Program and Environment of the University of California, San Francisco Campus.
“Perhaps most of this degraded microplastic, but that does not mean that you are not exposing yourself for these other cooler microplastics,” Woodruff said. The larger particles can continue to affect the intestine, which in turn could affect the rest of the organism, said Camlan.
In addition, scientists believe that certain chemicals of plastics, such as phthalates, bisphanol A and fire retardants, can damage human health. “There are many years of study on these plastics,” Woodruff said. “But we still have a lot of science to say: ‘Wow, I don’t want to expose myself to more plastics.'”
Tyler said that the New Mexico University Laboratory had done the best possible job for such an incipient field. “Matt’s group is a pointer,” he said.
But, as with any incipient science, you have to take things with caution. First, these tiny particles are extremely difficult to measure. And no one has yet repeated the investigation to see if the results are maintained. The big question is whether everything they are measuring is really plastic, or if part of it is lipid, that they can have a similar chemical, but that are found naturally in the organism.
“The estimates they have about the amount in the brain seem high,” Woodruff said. But even if they were, he said, “that would not invalidate the findings that more plastics are observed over time. And that is actually very consistent with what we know about the production of plastic.”
Control health risks
There is a question that Camlan and Garcia believe that they have begun to answer with some security. It is what they started: how much plastic is there in our body?
They are now prepared to explore possible links between certain doses and results in human health, such as heart disease, fertility problems and multiple sclerosis.
And they are starting an animal experiment to understand what dose could be harmful.
Teya Garland, a pharmaceutical student, was starting that process in the laboratory. With a mask to avoid inhaling particles, I introduced pieces of what seemed chalk colored in a machine that howled creekly while frozen and pulverized the plastics. Over time, researchers will feed mice with them and study how different levels and types affect their brain and behavior.
The pieces came from Hawaii beach where Garcia and others collected about 800 kilograms of plastic waste and about 200 kilos of networks. Volunteers clean that amount every few weeks.
“It is one thing to watch a photo,” Garcia said, watching a video he recorded with his phone. “Seeing it when we were there, opens your eyes,” he added. All imaginable uses of plastic-downtown food, chlorine bottles, cigarettes, plastic bags and even laboratory material-seemed to be represented on that beach and in the ocean that extended further. And every day he broke down, becoming more and smaller.
One day, part of it could end in us.