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Microplastics in the human body: What we know and don’t know

Few places on Earth – or in our bodies – seem to be free of microplastics.

Researchers in recent months have announced the discovery microplastics move in the blood of a handful of anonymous donors and deep in the lung tissue of about a dozen patients awaiting surgery. Another study recently reported find microplastics in the placenta.

These discoveries have generated a dizzying array of headlines that some may find relevant – but science still can’t solve.

What recent research clearly shows is that microplastics are ubiquitous, these particles enter the human body frequently during breathing or through the consumption of food or drink, and they find their way into vital body systems.

Several studies of laboratory animals and cells grown outside the body suggest that there are reasons to be concerned about how these microscopic pieces of plastic affect our physiology.

What is even less clear is what health risks, if any, these particles pose at the concentrations they have been found in. The scientists say the series of recent studies and headlines represent their first steps in understanding the impact these particles have on our daily lives.

“We have identified microplastics in the air we breathe. We found microplastics in the lungs. The next step is – so what? Does it matter that there is plastic in the lungs? “We don’t know the answer to that question at the moment,” said Laura Sadofsky, a researcher in respiratory medicine at Hull York Medical School, UK.

“This is going to take another 10 years, 15 years before we can understand what’s happening here.”

Dick Vethaak, emeritus professor of water quality and health at Vrije Universiteit

From 1950 to 2015, Plastic production grows at an average of 8.4% per year, according to an estimate published in the journal Science. Scientists have reported finding microplastic pollution 5 miles above sea level (due to snow near Mount Everest) and also in the deepest parts of the oceans (including from seawater in the Marianas Trench).

Dick Vethaak, emeritus professor of water quality and health at Vrije Universiteit Amsterdam, says scientists are just beginning to confront the potential consequences for human health.

“For me, what is most alarming is that we are very likely to have to deal with increasing concentrations of microplastics in the coming decades,” Vethaak said. “This is going to take another 10 years, another 15 years before we can understand what’s happening here, if we’re facing a serious risk.”

What are microplastics?

Studies show that microplastics can be found in the air we breathe, the dust that accumulates on our floors and in the shellfish we buy at the grocery store.

There is no single definition for what microplastics are, but researchers generally describe them as any plastic particle less than 5 mm in size, but larger than 1 micrometer.

They are usually smaller than the smallest grain of sand or a fraction of the width of a human hair.

The shape, size, and chemical composition of these particles also vary, and researchers often focus on identifying the most common polymers.

These are the smallest particles that researchers are most interested in, Vethaak said. The researchers suspect they are more likely to penetrate deep into the body and pass through the protective inner membranes.

Finding microplastics in the body requires meticulous and careful work. The risk of contamination is always present.

“There’s plastic in every lab product we use,” said Kurunthachalam Kannan, an environmental chemist and professor in the department of pediatrics at NYU School of Medicine. Exposure to microplastics is about 15 times higher than that of adults. “You have to be very careful in making these types of measurements.”

Sadofsky wears a cotton lab coat.

Initial findings

Most studies to date on microplastics have been studies with a relatively small sample size focused on microplastics identification and exposure determination.

“Exploratory studies,” says Kannan.

Among the most exciting recent findings are Sadofsky’s study, which found microplastics in living human lung tissue, Vethaak’s discovery of microplastics in blood, and Kannan’s work showing that infants can lie inside number of people most frequently contacted.

In Sadofsky’s study, researchers collected lung tissue from 13 people undergoing chest surgery. They break down that lung tissue using a strong acid, then filter out the synthetic particles.

They then characterize the remaining material – most of which is plastic – and use analytical technology to characterize the plastic. The researchers also ran blank samples without lung tissue to ensure quality control.

Eleven of the 13 patient samples had microplastics in their lungs, for a total of 39 individual small pieces of plastic.

“We looked at human lungs in different regions – upper, middle, and lower – we found microplastics in all regions of the lung, including the lower regions,” says Sadofsky.

It’s not clear how well the findings might apply to others.

“They’re in the hospital for lung surgery but we don’t know if microplastics have any effect on their health and we don’t know if the average person in Hull has similar levels of microplastics,” says Sadofsky. are not.

In another study from the Netherlands published last month, researchers processed the blood of 22 anonymous donors, finding microplastics in 17 samples.

This is the first time microplastics have been found in a blood sample, Vethaak said. It’s not clear how the people studied were exposed to microplastics or whether it had any consequences on their health.

“We don’t know too much about their background,” said Vethaak, one of the study’s authors.

Many questions remain unanswered.

“There is plastic circulating in our bodies,” Vethaak said. “Are they eliminated? What is the excreted part? Are they stuck somewhere in the system? Do they accumulate in certain organs? Do they cross the blood-brain barrier or the placenta? ”

The risks from microplastics may favor certain groups.

Kannan’s lab analyzed the stools of 9 infants and 10 adults.

“Infant stool samples contained 15 times more PET than adult samples,” said Kannan, referring to polyethylene terephthalate, which is common in clothing and food containers.

Kannan suspects infants and other children have a much higher exposure because they crawl on the floor which can be filled with microplastics, put most things in their mouths and often rely on plastic cups, mouthpieces and toys. .

“There are many sources of exposure for infants,” says Kannan.

Future research

Studies involving animals or cells grown in a laboratory setting show that microplastics can induce inflammatory responses, oxidative stress, and cell damage. But many of these studies involved exposure to highly concentrated or commercial-quality plastics, the study said.

Data from the most recent studies could spur more research on microplastics and health.

“None of these studies associated any health outcomes. Kannan said. “Research is in its infancy.”

“The question is how toxic are they and to what extent are they toxic?”

Kurunthachalam Kannan, environmental chemist and professor of pediatrics at NYU . School of Medicine

Kannan said the recent findings have provided a basis for the US federal government to invest in studies that focus on toxicology or epidemiology.

Now the contact is clear, he said. “The question is how toxic are they and to what extent are they toxic?”

European researchers are stepping up their efforts.

In 2019, the Netherlands started 15 projects on microplastics and then expanded Additional funding for a microplastics research consortium last year.

European Union ctransferred more than 32 million dollars towards years of research on micro- and nano-plastics from 2021-2025.

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