Plastic is harming our body's cells. Here's how

A new study has found for the first time that tiny plastic particles found in water and air affect the function of our body’s cells and might damage them. Here are all the details.

On November 1, a tax on disposable plastic products started to be enforced in Israel in order to reduce the amount of plastic products that arrive at record speed from the store to the home and then the landfill. 

Beyond the waste generated when these products pollute the environment in massive quantities, the plates, cups and plastic cutlery thrown in the trash can break up into microplastics - tiny plastic particles, found almost everywhere scientists have searched, from the depths of the oceans to snowy mountain peaks, from milk to beer and mineral water. 

Plastics can never completely decompose.

Until now, the scientific world was divided on the question of whether microplastic particles have a detrimental effect on people. 

Now, a new study from Spain shows for the first time that microplastic particles tend to stick to the cell membranes that compose our bodies, and that they can cause problems in the proper functioning of the cell. 

To what extent should this news worry us? And what can we do about it?

Since the start of the mass use of plastic in the middle of the 20th century, the amount of plastic produced each year has only increased (with a slight decrease of 0.3 percent in 2020 due to the corona epidemic), and in 2019 over 360 million tons of plastic were produced. This is approximately equal to the weight of the total population of the world. 

"Contrary to popular belief, plastic does break down in nature, but it breaks down into smaller particles, micrometers (millionths of a meter) and nanometers (billionths of a meter), in a process that can take hundreds of years," explained Dr. Ines Zucker, head of the Nanotechnology Laboratory at Tel Aviv University. 

This microplastic is joined by plastic particles that are pre-produced as a few micrometers in size, such as plastic beads that are found in various cosmetic products.

"The smaller the plastic, the easier it is to get through barriers in our body," Zucker explained. "Studies have shown that microplastics can cross barriers in the digestive tract and enter the bloodstream. It should be noted that the extent of the danger is still unclear: Some studies claim that it’s very harmful to humans, while others state that it doesn’t cause significant damage."

The new study examined the interaction between microplastics in sizes of 0.8-10 micrometers and the cell membrane that encloses our body’s cells. In the first phase, researchers used a computer model to test the effect that microplastic particles would have on the cell membrane and the biological material in it. They found that each particle leads to an increase in the physical stress of the membrane. 

"Mechanical pressure on the cell membrane can affect the function of proteins and channels in the cell membrane and strain them," Zucker explained. 

It should be noted that because the cell membrane is similar in behavior to a liquid, it can move freely and release mechanical pressure on it, but the researchers' assumption is that the release time by the cell membrane is slower than the rate at which particles are being absorbed into it. Therefore, the tension in it increases.

In the second stage, the researchers tested the findings and assumptions of the computer model in an experiment: they created an artificial cell membrane that simulates the structure of the human cell membrane, and soaked it in a liquid containing 10 one-micrometer microplastic particles. They found that the pressure measured in the cell membrane increased in direct proportion to the microplastic concentration, which gradually adhered to the membrane, in accordance with the findings reflected on the computer model.

In the third phase of the experiment, the researchers used living red blood cells, which are identical to those found in the blood vessels in our bodies. They isolated a single blood cell and applied increasing pumping pressure to it, until it disintegrated and was pumped into the device. The experiment found that when the blood cell was inside a solution containing 0.5 micrometer of microplastic, it disintegrated much faster than in the control experiment, where the solution in which the cell was found didn’t contain microplastic. According to the researchers, these measurements show that the presence of microplastic increases the tension in the membrane of red blood cells, which undermines its stability.

An ever-increasing danger

Zucker said that the results of the study may reflect general damage to our bodies and how microplastics affect our health. However, it’s still unclear what exactly the effect of the increase in membrane tension is on cell and body function. 

"It should be noted that this is a basic study, which alone can not yet determine whether exposure to microplastics has chronic or acute health consequences for humans," she said.

Zucker also noted that there are also problems with the type of microplastic that the researchers used in the experiment.  

Zucker adds that most laboratories worldwide that study microplastics, including the one that conducted this study, work with uniformly sized beads, in a pure polymer composition, and have a perfect round shape and don’t resemble the microplastic particles in most products. Zucker recently created a more "realistic" microplastic in her lab, and says that from initial results of an experiment she conducted in intestinal cells, this microplastic is more dangerous to cells than its "generic" counterpart from the lab. 

Either way, as mentioned, the amount of microplastics in the environment is only expected to increase in the coming years and decades - and therefore, if it does cause damage to cell membranes in our body, its extent is only expected to increase. 

"We still need to find out whether exposure to microplastics will cause us diseases and shorten life expectancy, but there is no doubt that the fact that we consume so much disposable plastic, especially here in Israel, is a cry for generations," Zucker said. "Using plastic to drink something for 10 seconds, knowing that it will remain in the world for decades and centuries, is irresponsible for future generations. 

“Until they develop a real substitute for plastic from consumables, there is no escape: one should simply use less of it," she concluded.

Zavit is the news agency of the Israeli Association of Ecology and Environmental Sciences. This article was first published on the Jerusalem Post's sister website, Walla!