Microplastics: Should we be concerned?

Pollution is globally recognized as a significant environmental hazard, posing a severe threat to the earth’s ecosystems and the organisms that populate it.

Plastic waste has been a major environmental concern for decades.

However, new technology and detection techniques have identified a growing concern -minuscule particles of plastic called ‘microplastics’.

These tiny fragments have the potential to cause huge damage to the world and its inhabitants, with studies showing their worrying impact on animal, plant, and human health.

What are microplastics?

The term ‘microplastic’ refers to tiny fragments of plastic that measure less than 5 mm. However, some are so small that they can only be detected through powerful microscopes.

These particles enter ecosystems via the breakdown of larger plastic debris, such as food packaging and single-use cups.

Other sources include synthetic fibres in clothes and fine layers of plastic laid down on roads from car tyres.

Additionally, microplastic particles are intentionally manufactured for inclusion as abrasives, fillers, or emulsifying agents in household products such as cosmetics and cleaning materials.

While research into microplastics is still relatively new, the studies carried out show them to be ubiquitous in soil, water, air, food, and living organisms, including humans.

Each year, around 400 million tonnes of plastic are produced globally [1].

Of this, just 7 per cent is recycled, with the remainder being dumped, incinerated, or sent to landfill [2]. Most of this waste will eventually degrade, adding to the proliferation of microplastic particles and highlighting the urgent need for improved quantification tools.

Impacts of microplastics

Studies conducted in small invertebrates and other animals have shown that microplastic build-ups are causing toxic effects at the site of accumulation.

Research using zebrafish [3] noted intestinal inflammation, while investigations using mice highlighted reproductive abnormalities [4]. Meanwhile, neurotoxic effects were recorded in fish as a result of microplastic build-ups in their brains [5].

As with most studies, animal models are usually excellent indicators in determining the effects of chemicals and other environmental stress factors on humans. Consequently, it is now considered likely that microplastics could have similar consequences and effects when humans are exposed to them.

Due to their minuscule size, microplastics can transfer easily through the environment into organic tissues and organs.

As microplastics can be inhaled and ingested through air, water and food, most novel studies in humans have been focused on the gut and lungs, with many of these revealing impacts on cell functionality in lung tissue [6] and gut microbiome health [7].

Studies have estimated that the average person consumes 39,000 to 52,000 microparticles every year through ingesting contaminated food and drink products. Seafood is especially affected, due to plastic pollution being present in every aquatic environment on Earth [8].

The sheer scale of oceanic plastic pollution is easily observable through the ‘Great Pacific garbage patch’ – a 1.6 million km² ‘island’ of waste debris, roughly three times the size of France, located in the Pacific Ocean between North America and Japan [9].

Sadly, water pollution by plastic is not limited to seawater- it is also a substantial contaminant of drinking water from freshwater sources.

This is a particular problem in developing countries, where water treatment is not widespread, waste production is high, and import of plastic waste from developed countries for payment is common.

The decline of air quality from industrial activity is also likely to play a role in human exposure, with research revealing that airborne microplastic particles persist from remote regions and urban environments alike.

A 2020 study of moss samples growing in remote areas of Ireland found that 13-27 per cent of all particles identified were suspected microplastics.

Plants absorb microplastic particles directly from the atmosphere, contaminated water sources, and rainfall, further facilitating the movement of plastics through the food chain [10].

Microplastics have been found in the world’s most remote and extreme regions, including Mount Everest [11], the Mariana Trench [12] and the Arctic [13] due to human activity, contaminated rainfall, and wind flow.

More recently, they have also been detected in human breast milk [14] and placenta [15], suggesting that cross-contamination between mother and unborn child is another potential and worrying possibility.

In addition, a March 2023 study using mice indicated that microplastics can cross the blood-brain barrier and can be detected in brain tissue a mere two hours after ingestion [16].

Microplastic contamination has already been shown to be widespread throughout the human body.

A 2022 study discovered the presence of microplastics in the blood of 17 of 22 healthy volunteers enrolled [17], indicating that microplastic contamination of blood, organs and tissues is likely a common occurrence.

Future research and conclusion

The study of microplastics and their impact is still in its infancy.

As a result, the impact of human exposure to them and any long-lasting health implications are still largely uncertain.

However, scientists’ increasing focus on the development of technology to detect and analyse microplastics will reveal their true impact on humans.

New research in human gut microbiome profiles has suggested that bacteria that reside in and aid our digestive system have now evolved genomes with plastic-degrading capabilities.

Discoveries such as this show how little we know about microplastic exposure and its impacts on bodily functions and human health.

There is no doubt that the term ‘microplastics’ will become more commonplace in the next few years as the research gap closes and more insight is gained into their impact on our health.

Swift action will be essential, and some countries have already adopted policies to minimise dumping practices and reduce plastic use.

However, the effectiveness of such environmental initiatives, primarily in developed countries, is yet to be seen. Furthermore, there needs to be improved efforts to stop richer nations from shipping their plastic problem overseas.

The United Kingdom (UK) produces around 2.5 million metric tonnes of plastic every year, [18] with roughly 60 per cent of this waste being exported to other countries such as the Netherlands for recycling.

Unfortunately, a 2022 article published by Leiden University, Netherlands reports that, while 38 kilo tonnes of ‘recycled’ Dutch plastic waste are shipped to non-EU countries such as Turkey and Malaysia for recycling, a combination of poor quality of material in terms of recyclability and limited capacity to manage the volumes shipped means much of this waste ends up in the sea [19,20] causing extreme ecological damage.

Microplastic facts and tips

• Bottled water can contain an average of 325 microplastic particles per litre compared to 5.5 particles per litre for tap water. To avoid this, consider buying a reusable non-plastic water bottle [21]. Tap water can be further filtered to reduce plastic contamination.
• Using plastic containers to reheat food in a microwave significantly increases the number of microplastics released into your food [22]. Swapping out plastics for ceramics can reduce the risk of exposure.
• Limit your exposure to microplastics by:
  • Regularly vacuuming your home.
  • Filtering tap water.
  • Using air purifiers.
  • Reducing shellfish consumption.
  • Wearing a mask in industrial environments such as construction sites and factories.
  • Maintaining a healthy diet full of green vegetables (broccoli, cauliflower, asparagus), citrus fruits, and natural spices (ginger, turmeric).
  • Staying hydrated – this helps the body to flush out toxins and supports digestion.

• Reduce your generation of microplastics by:
  • Avoiding single-use plastic containers/bottles.
  • Using ceramic containers to reheat food rather than microwaveable plastics.
  • Buying plastic-free cosmetics and detergents.
  • Wearing organic/eco-friendly clothing.
  • Using public transportation.
  • Separating and recycling your plastic waste.

Related: Microplastic found in human hearts

Paul Johnston is a Graduate Trainee Regulatory Executive at G&L Healthcare Advisors.

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