Tiny but deadly: Microplastics now running through our hearts

Plastic has contaminated our soil, our oceans and the air we breathe. But now it is polluting our bodies. Tiny plastic particles less than five millimetres wide (equivalent to a sesame seed), called microplastics, were previously found in the human digestive tract, lungs and blood. As if that wasn't bad enough, last month a study found microplastics in human hearts.

We have been consuming microplastics in our food and water for long. However, how microplastics are getting inside our body has not been definitively identified yet, as the air we breathe also contains invisible plastic fragments even thinner than human hair, such as fibres shed by our own clothes, carpets and upholstery. 

These tiny particles can also pass through other body openings as well. However, most researchers are of the view that people are more likely to inhale tiny, invisible plastic fibres floating in the air around them than to ingest them with their food.

Some of the significant sources of microplastic, especially in Bangladesh are plastic bottles, plastic containers, one-time cups or plates and polythene bags.

Despite local city corporations banning single-use plastic bags back in 2002, the country has gradually relapsed into the widespread use of single-use plastic in all kinds of retailing. The withdrawal of the 5% supplementary duty on all types of polythene and plastic bags in FY 2022–23 aggravated the problem further.

According to a recent study, more than 2.5 crore polythene bags are thrown away after being used only once in Dhaka every day. According to Department of Environment sources, Bangladesh produces 10.95 lakh metric tonnes of plastic waste every year.

Worldwide, an estimated 390.7 million metric tonnes of plastic were produced in 2021 and this is only likely to increase further if we do not take any drastic measures.

Organs at risk of contamination

Since 2019, when the World Health Organisation (WHO) called for more research on microplastics, microplastics have been found in the human blood, heart, lungs, intestines, placentas of foetuses, newborns and so on.

On 13 July this year, the American Chemical Society (ACS) published a study titled "Detection of Various Microplastics in Patients Undergoing Cardiac Surgery," for which a team from Capital Medical University, the Chinese Academy of Medical Sciences and Peking Union Medical College in Beijing examined specimens collected from 15 patients who underwent cardiac surgery, reports Forbes. They found microplastics in many heart tissues.

In April 2022, researchers from the University of Hull and Hull York Medical School also found microplastics in the deepest section of the lung, which was previously thought to be impossible due to how narrow the airways are, reports the Guardian. Microplastics have previously been found in human cadaver autopsy samples, but this was the first study to show them in the lungs of live people.

In March of the same year, a study done by the Vrije Universiteit Amsterdam found plastic particles between 700 and 500,000 nanometers in the blood of 17 out of 22 participants (80%). Seven hundred nanometers is around 140 times smaller than the width of a human hair, writes The Wire's Aathira Perinchery.

What happens now?

Researchers have yet to reach any conclusions about the extent of harm microplastics cause to our bodies. However, everyone agrees that it is a matter of grave concern.

Talking to National Geographic, Albert Rizzo, the American Lung Association's chief medical officer, says the science is too unclear to draw conclusions.

Yet the most relevant analogy may be the decades-long effort to convince the government that smoking causes cancer. "By the time we got enough evidence to lead to policy change, the cat was out of the bag," said National Geographic's Albert Rizzo. "I can see plastics being the same thing. Will we find out in 40 years that microplastics in the lungs lead to premature ageing of the lungs or to emphysema? We don't know that. In the meantime, can we make plastic safer?"

Janice Brahney, a biochemist at Utah State University who studies how dust transports nutrients, pathogens, and contaminants, says she is concerned because plastic production continues to increase dramatically while so much about microplastics remains unknown.

"It is alarming because we are far into this problem and we still don't understand the consequences, and it is going to be very difficult to back out of it if we have to," she says.

Much like Albert Rizzo and Janice Brahney, many other scientists have expressed similar concerns.

Few studies, like the one conducted in South Korea and published in the National Library of Medicine in April 2023, show that microplastics can affect the human body by attacking various organs from within.

Microplastics have been found to stimulate the release of endocrine disruptors, also referred to as hormonally active agents, which can harm the human body by causing various cancers and reproductive-system disorders.

Microplastics may cause changes in the intestinal microbiome, resulting in an imbalance between beneficial and harmful bacteria, leading to gastrointestinal symptoms such as abdominal pain, bloating and changes in bowel habits.

In addition, multiple studies have shown that microplastics can carry other toxic chemicals, such as heavy metals and organic pollutants, during adsorption, adversely affecting the human body.

Chronic exposure to low concentrations of microplastics in the air could even cause respiratory and cardiovascular diseases, reports the study "Health Effects of Microplastic Exposures: Current Issues and Perspectives in South Korea."

According to a study published on IntechOpen, researchers show that human exposure to microplastics could lead to oxidative stress, DNA damage, and inflammation, among other health problems. Particularly when inflammation becomes chronic, this can pave the way to severe health problems.

If things are allowed to continue on this path, the future looks bleak. Awareness at an individual level can only get us so far, the biggest plastic polluters must be held accountable and it is imperative that strict policies are drawn up and implemented adequately before it is too late to turn the tide on plastic pollution.