What we know and what we don’t know

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

Researchers in recent months have announced the discovery of microplastic particles that travel through the bloodstreams of a handful of anonymous donors and are embedded deep in the lung tissue of about a dozen patients waiting for surgery. Another recent study reported finding plastic particles in the placenta.

These discoveries have led to an astonishing string of headlines that some may find disturbing – but the science is still far from settled.

What the latest research shows so far is that microplastics are ubiquitous, that these molecules regularly enter people’s bodies during inhalation or through the consumption of foods or drinks, and that they find their way into vital body systems.

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

What remains less clear are the health risks, if any, posed by these fine particles at the concentrations found. Scientists say the plethora of recent studies and headlines represent their first steps toward understanding the impact these particles have on our daily lives.

“We’ve detected microplastic particles in the air we breathe. We’ve found plastic particles in the lungs. The next step is – so what? Does it matter if there’s plastic in the lungs?” said Laura Sadowski, a researcher in respiratory medicine at Hull York School of Medicine in UK We don’t know the answer to that question at the moment.

“It will take 10 years, another 15 years before we can understand what is going on here.”

Dick Vitak, Professor Emeritus of Water Quality and Health at VU

From 1950 through 2015, plastic production grew about 8.4 percent each year on average, according to an estimate published in the journal Science. Scientists have reported finding microplastic pollution more than 5 miles above sea level (from snow near the summit of Mount Everest) and also in the deepest parts of the ocean (including from seawater in the Mariana Trench).

Dick Vitak, professor emeritus of water quality and health at Vrije Universiteit Amsterdam, said scientists are just beginning to deal with the potential consequences for human health.

“For me the most worrying thing is that we are very likely to be dealing with increasing concentrations of microplastics in the coming decades,” Vithak said. “It’s going to take 10 years, another 15 years before we can understand what’s going on here, if we’re dealing with serious risks.”

What is microplastic?

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

There is no single definition of what a microplastic is, but researchers generally describe it as any particle of plastic that is less than 5 mm in size, but larger than 1 micrometer.

They are often 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 usually focus on identifying the most common polymers.

It’s the smallest particles that worry the researchers, Vithak said. Researchers suspect that they are more likely to penetrate deeply into the body and pass through the protective membranes inside.

Finding microplastics inside the body requires careful and careful work. There is absolutely no risk of contamination.

said Kuruntachalam Kanan, an environmental chemist and professor in the department of pediatrics at New York University School of Medicine, who found in a recent study that children’s exposure to microplastics was about 15 times that of adults. “You have to be very careful doing these kinds of measurements.”

Sadofsky wore a cotton lab coat during the experiments.

early results

Much research has been done to date on microplastics with a relatively small number of samples focusing on identification of microplastics and exposure determination.

“Exploratory studies,” Kanaan said.

Among the most intriguing discoveries are Sadovsky’s research, which found microplastics in the lung tissue of living people, Vithak’s discovery of microplastics in the bloodstream, and Cannan’s work, which showed that children may be among those most frequently exposed.

In the Sadofsky study, researchers collected lung tissue from 13 people who had undergone chest surgery. They scraped up lung tissue with a strong acid, and then filtered out the synthetic particles.

They then characterized the remaining material – mostly plastic – and used an analysis technique to characterize the type of plastic. The researchers also performed blank samples without lung tissue to ensure quality control.

11 of the 13 samples from patients had microplastics in their lungs, for a total of 39 microplastics.

“We’ve looked at the human lungs in the different regions – the upper, middle and lower lungs – we found microplastic particles in all areas of the lungs, including the lower levels,” Sadovsky said.

It is not clear to what extent the findings may apply to others.

“They are in the hospital for surgery on their lungs, but we have no idea if microplastics have any effect on their health and we have no idea if the average person in Hull has similar levels of microplastics,” Sadowski said.

In another study from the Netherlands published last month, researchers treated the blood of 22 unknown donors and found microplastic particles in 17 samples.

Vitak said this is the first time microplastics have been found in blood samples. It is not clear how those studied were exposed to microplastics or if they had any health consequences.

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

Many questions remain unanswered.

“There is plastic going around in our bodies,” Vithak said. “Do they excrete? What fraction are they excreted? Are they stuck somewhere in the system? Do they accumulate in certain organs? Do they cross the blood-brain barrier or the placenta?”

Microplastics’ risks may skew toward certain groups.

Kenan’s lab analyzed the stools of nine children and 10 adults.

“Children’s stool samples contained, on average, 15 times more than adult samples,” Kanaan said, referring to polyethylene terephthalate, which is common in clothing and food containers.

Kinan believes that babies and other children are exposed much higher because they crawl on floors that can be laden with microplastics, put everything in their mouths, often relying on plastic drinking cups, teethers and toys.

“There are many sources of exposure for infants,” Kanaan said.

future research

Studies in animals or cells grown in laboratory environments indicate that microplastics can cause inflammatory responses, oxidative stress, and cell damage. Research says that many of these studies involved exposures to highly concentrated or commercial-grade plastics.

Data from the latest studies could drive further research into the field of microplastics and health.

None of these studies are associated with any health outcomes. It’s all a measure of “Are we exposed?” Kanaan said. “Research is in its infancy.”

“The question is how toxic are they and at what level are they toxic?”

Kurunthachalam Kannan, an environmental chemist and professor in the Department of Pediatrics at New York University School of Medicine

Kinan said the latest findings laid the foundation for the US federal government to invest in studies focused on toxicology or epidemiology.

He said the exposure is now clear. “The question is how toxic are they and at what level are they toxic?”

European researchers are stepping up their efforts.

In 2019, the Netherlands launched 15 projects in the field of microplastics and then provided additional funding to the Microplastics Research Consortium last year.

The European Union has allocated more than $32 million to five studies on micro and nanoplastics from 2021 to 2025.

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