Is plastic harmful to humans?

Recent news reports have put the issue of microplastics and their effects on the human body squarely in the limelight. From seafood to bottled water and tap water, alarming new studies are showing that more plastic is entering the human body than first thought.

Whether or not ingesting plastic is harmful to human health is still being studied.

In this article, we will look at the various ways in which plastic could be entering the human body, and take a look at the effect this could be having on humans.

Eating seafood

Our seas and oceans are awash in plastic. As an example, The Great Pacific Garbage Patch is thought to cover an area four times the size of France and is made up primarily of plastic.

Plastic does not biodegrade in the same way that organic materials do. Instead, plastics undergo a process called ‘photodegradation’. This means they begin to decay when exposed to UV light from the sun. This photodegradation causes the plastic to become brittle and break apart, shattering into smaller and smaller pieces.

Once plastics are measured at under 5mm they are classed as microplastics

Once these pieces are measured at 5 mm or smaller, they are categorised as microplastics.

Recent studies estimate the number of microplastic particles in the ocean at between 15 and 51 trillion pieces. To put this in comparison, there between 150 billion and 250 billion stars in our galaxy. Therefore, there are roughly 100 times more plastic particles in the ocean than there are stars in the Milky Way.

Why does this matter?

Plastic causes a number of problems for marine life, including strangling seals and dolphins, and entangling birds, preventing them from flying. But for the purposes of this article, we will look at one specific issue, one that is affecting not only animals but humans as well: plastic in the ocean is entering the food chain.

More than 200 marine animals have been documented to have eaten plastic, including turtles, whales, seals, birds and fish.

Some examples of marine life ingesting plastic include:

  • Sea turtles ingesting plastic bags, mistaking them for jellyfish
  • Fish swallowing microplastics, mistaking them for smaller fish

Not only can tiny pieces of plastic look like food to marine animals, but it can also smell like food.

Floating plastic attracts algae, which forms part of the diet of many different types of marine animals. This just further increases the chances of plastic being ingested.

Up the food chain

Every animal in the sea is part of a complex and delicate food chain. Tiny fish are eaten by slightly bigger fish, which are then eaten by bigger animals. On and on it goes, up the food chain.

The result is that the contents of the stomach of small fish will travel up the food chain. The microplastics are transferred but often not expelled.

Plastic particles have been documented in tens of thousands of organisms, and more than 100 species of marine animals.

People the world over rely on the sea as a major source of food. It’s no surprise then, with the extent of the plastic contamination, that microplastics are being ingested by human beings.

Researches at Ghent University in Belgium calculated that people who eat shellfish could be ingesting up to 11,000 plastic particles in their seafood each year.

Bisphenol A (BPA)

Bisphenol A (BPA) has been used in the plastics industry for over 40 years. It is used to harden plastics, and is used in the manufacture of medical devices, water bottles, the linings of aluminius cans, dental sealants, and much more. It is everywhere.

The debate over the safety of BPA still rages on.

Some studies have shown that BPA can seep into food and beverages from containers that are made with BPA.

There have been concerns raised that plastic bottles will give off more plastic particles when heated. However, experiments have been carried out in which plastic bottles have been heated up to 60⁰C, and it was observed that the levels of chemicals that shift to food and drink are still very low – far below what is considered unsafe for human consumption.

However, the Food and Drug Administration (FDA) has said that BPA is safe at the low levels that occur in foods.

The FDA’s British counterpart, the Food Standards Agency (FSA) has also said that BPA is safe at the very low levels present in food.

The European Food Safety Authority (EFSA) has also assessed the available evidence on BPA and found that dietary exposure to BPA is not a health concern for any age group.

When it comes to what we put into our bodies, and those of our children, it is right to be vigilant. Although there is still debate over the safety of BPA, it should be remembered that the food safety authorities of the United States, the United Kingdom, and the European Union, have all publicly declared that, based on current evidence, BPA is not a health concern for any age group.

If more evidence becomes available, we will update this page.

Plastic in the air

60 million metric tons of plastic textile fibres are produced each year, about 16% of the world’s plastic production.

According to a study carried out by a team of French scientists, some of these plastic fibres are present in the air we breathe. 67% of indoor fibres were from natural materials, with the remaining 33% contained plastic.

The concentration of plastic fibres is substantially higher indoors than outdoors.

The study goes on to say that many of these fibres are cleared naturally from the body, but some may persist in the lungs and can cause inflammation, particularly in people with compromised clearance mechanisms.

The study claims that babies may be at particular risk of ingesting these fibres, owing to crawling on the floor, and frequent hand-to-mouth contact.

Studies among nylon workers found there was no increased risk of cancer, although there is a higher risk of respiratory illnesses.

In summary, there is evidence that plastic microfibres are present in the air we breathe, and there is evidence that some of these fibres are being ingested into the body. What is less clear is whether or not this constitutes a risk to human health.

If you’d like to learn more, take a look at the study on Science Direct.

Do we have plastic inside us?

From reading about the various ways plastic can find its way inside the human body, it is no surprise then that recent scientific studies have confirmed that plastic can indeed be found inside most human bodies.

Eight participants took part in the trial, and all eight were found to have microplastic particles in their stool. The sizes of the particles ranged from 50 to 500 micrometres.

Of the ten different plastics tested for, nine were detected. The most common of which were polypropylene and polyethylene terephthalate.

The authors of the study estimate that more than 50% of the world’s population might have microplastics present in their body.

Phillip Schwabl, who led the study, said: This is the first study of its kind and confirms what we have long suspected, that plastics ultimately reach the human gut. Of particular concern is what this means to us, and especially patients with gastrointestinal diseases.

Another study, carried out in Italy, tested for the presence of microplastics in eighteen different soft drinks, including Coca-Cola, Fanta and Sprite. The results showed that every one of the eighteen soft drinks tested contained microplastic particles. Seven Up topped the list, with 18.89 microplastic particles being found per litre of the drink.

Similar studies have been carried out on all manner of seafood.

Make no mistake: microplastics are finding their way into our food and drink, and we are ingesting

Is the plastic in our bodies harmful to us?

So far in this article, we’ve discussed the ways in which plastic may be entering our bodies, and the scientific evidence that proves plastic is indeed found in much of the world’s population. But this article is entitled ‘Is plastic harmful to humans’, so let’s look at what we know.

The truth is, there is not enough evidence at this time to say one way or another.

All we have at the moment is speculation, rather than hard evidence.

According to the Centre national de la Recherche Scientifique (The National Center for Scientific Research in France), microplastics have the capacity to “bind to organic pollutants in the environment such as PCBs, dioxins or PAHs”. It has been speculated that once inside the human body, microplastics could be releasing harmful chemicals.

The lead scientist behind the study that found microplastic particles in human stool recently stated: “Now that we have the first evidence for microplastics inside humans, we need further research to understand what this means for human health.”

The UK Government recently admitted there is “little evidence” available on the effects of microplastics on the human body.


This is still very much an area where more research is needed.

It is quite clear that microplastics can be found in food and drink that is being consumed by people all over the world. The research is also clear on the fact that this microplastic is being ingested by human beings.

What is less clear at this stage, is whether or not the plastic inside us is having a negative impact on our health.

We will keep this page updated as more research is published on the subject.