• Researchers concerned over increased accumulation of microplastics in bodies
• Regulators, experts point out challenges in removing microplastics from food chain, environment 

Microplastics, plastic particles ranging in size from 5 mm to 1 nm, have invaded every facet of life on earth, being detected in air, surface water, coastal beaches, sediment, and food, even having been discovered in remote and pristine locations, including the Antarctic, deep ocean trenches, and Arctic sea ice. 

While research on whether microplastics pose threats to human health is still in its infancy, a growing body of evidence indicates adverse health effects of microplastics exposure on living organisms.  

According to the US Environmental Protection Agency, there are two types of microplastics: primary microplastics are intentionally manufactured in small sizes for their use in consumer products, such as cosmetics or biomedical products. Secondary microplastics are plastic particles that break down from larger plastic materials, such as food wrapping, tyres, and synthetic textiles. 

Microplastics are likely to degrade into smaller nanoplastics through chemical weathering processes, mechanical breakdown, and through the digestive processes of animals. 

According to University of Sri Jayewardenepura Faculty of Medical Sciences Senior Lecturer Dr. Sajith Edirisinghe, carcinogenic elements present in the environment can enter the body through microplastics, resulting in genetic changes that can cause the development of cancers. 

Outlining how microplastics could enter the human body, he said: “During inhalation and through food, microplastics become incorporated into the body and the food chain. Once it is in the lungs, it passes into the blood through the alveoli, and then gets lodged in the intestine, brain, lungs, heart, etc., which are terminal organs.” 

For microplastics to enter the human body through food and water, they first find their way into the food chain through degrading plastic waste in the environment, which leads to microplastic particles being consumed by marine organisms, eventually ending up in the fish consumed by humans through a process of bioaccumulation. 

“Humans are the terminal apex predator, so we get higher amounts of microplastics. Once it starts bioaccumulating, it will enter our bodies when we eat.” 

Microplastics are ubiquitous: for instance, when friction wears down tyres along with the road surface, plastic fragments are released into the air.

Can microplastics cause cancer?

Researchers have estimated that humans consume a ‘credit card’s worth’ of microplastics every week. 

As a study in Harvard Medicine notes, current technologies don’t yet enable researchers to quantify population-level microplastics exposures or gauge what proportion of those particles stay in our bodies. Nevertheless, their ubiquity in the environment along with preliminary findings from human cell and animal studies over the past decade have led to urgent calls for more research and regulation, the study notes. 

A 2024 study in Environmental Science & Technology notes that due to their small size, microplastics more easily enter and are distributed in the human body in comparison to larger particles, having been measured in human placenta, breastmilk, and liver. 

Researchers from the University of California, San Francisco have also found that the air pollution created by tiny pieces of plastic released into the air by tyres and degrading garbage may be causing respiratory and other illnesses. 

They found that these particles are linked to a variety of serious health problems, including male and female infertility, colon cancer, and poor lung function. The particles also may contribute to chronic pulmonary inflammation, which can increase the risk of lung cancer. 

Explaining the process, Dr. Edirisinghe noted: “When microplastics are present in the atmosphere or environment, they have a natural ability to absorb different chemicals. These chemicals are released when the plastic particles are trapped in terminal organs. Most of these chemicals like mercury and lead are highly carcinogenic. There is already proven research to show elements like bisphenol A (BPA) causing breast cancer.” 

Cancers aren’t the only risk: Dr. Edirisinghe noted that humans were also likely to develop other non-cancerous diseases like dementia due to microplastics. According to a study published in Nature Medicine in March, a greater accumulation of environmental microplastics and nanoplastics was observed in a cohort of decedent brains with documented dementia diagnosis than in an average person. 

Speaking to The Sunday Morning, National Cancer Institute Paediatric Oncologist Dr. Sanjeeva Gunasekera pointed out that while a direct association between microplastics and cancer was yet to be proven through global research, there was a theoretical risk of cancer as identified by research done on animals and through studies of chemical properties. 

“Even in Sri Lanka, cancers are increasingly occurring in young people, especially colorectal and lung cancer. Therefore, people have hypothesised that since microplastics are found in water and we ingest water, they can lead to colon cancers. Likewise, they hypothesise that inhaling microplastics in the atmosphere can cause lung cancer,” he noted, nevertheless stressing: “These are still theories.” 

The medical advice for avoiding microplastics exposure is to adhere to good health practices. Accordingly, Dr. Gunasekera advised against the reuse of plastic water bottles and using plastics of poor quality for children, as well as to take steps to avoid exposure to microplastic particles for those engaged in various industries, such as paint.

Policies and regulation

In Sri Lanka, microplastics exposure is rapidly becoming a serious concern at the national level. The damage from microplastics that are already in the environment is long-lasting, with the X-Press Pearl disaster of 2021 serving as a mark of the irreversible impacts of microplastic pollution. 

“It’s very, very difficult to remove microplastics from the environment,” Dr. Edirisinghe pointed out. “I think Sri Lanka will suffer for another 400 years due to the damage caused by the X-Press Pearl disaster. The debris we saw on the beaches only amounts to about 5–10% of the damage; many more tonnes of plastics are in the seabed. These will generate microplastics because the plastic nurdles will take at least 400 years to decay.” 

Nevertheless, regulation of microplastics remains a developing area. Speaking to The Sunday Morning, Central Environmental Authority (CEA) Waste Management Division Deputy Director General Shyamani Periyapperuma shared that there was no regulation concerning microplastics in Sri Lanka yet. 

“The regulations that exist are related to banning certain plastic items; there is no specific regulation concerning microplastics yet,” she said. 

“At present, we are spreading awareness about the issue, but it hasn’t reached the level of regulation, since some items such as toothpaste come with microplastics added intentionally. While there is some discussion on regulating such items, these discussions haven’t reached the level of banning yet.” 

Periyapperuma said that the CEA was currently engaged in ensuring that the use of microplastics was minimised. “If we were to regulate microplastics, we would need to monitor them as well. As yet, we have no facilities at that level. However, in future, there might be some regulation regarding stopping the intentional addition of microplastics and reducing other uses,” she added. 

While Dr. Edirisinghe noted that the Government was expending maximum effort in this regard, the best option, according to him, is for the public to be aware of the harmful nature of microplastics and refrain from discarding plastic waste irresponsibly. 

“Firstly, garbage disposal should be 100% accurate. People should be aware that their children and the future generations will be affected,” he said. 

He also commended the Government’s initiative to ensure that carry bags, commonly known as ‘sili sili’ bags, will no longer be available free of charge with effect from 1 November. The bags made of Low-Density Polyethylene (LDPE) and Linear Low-Density Polyethylene (LLDPE) fall under this category. 

The directive further requires traders to clearly display the price of such bags at their business premises and include the price on consumer bills.  

“People don’t realise the gravity of microplastics. The most important thing is making people aware that this is a threat. It is an unseen disaster created by mankind. The important message that we have to convey is that these plastics need to be disposed of properly,” said Dr. Edirisinghe.