What health risks do microplastics pose to us?

Microplastics are small plastic particles less than 5mm in size and they are an emerging environmental and health issue. Although more research is urgently needed to understand the full extent of the risks they pose to human health, what we do know is that plastic has been designed to be durable and despite recent awareness of the need to reduce plastic, in particular single-use plastic, its use is set to increase.

What does this mean for human health? Microplastics can enter our bodies through ingestion, inhalation and dermal contact. Ingestion largely occurs through microplastics entering our natural environment and ending up in our water systems via a number of routes, including surface run-off, waste water, pollution in the atmosphere, plastic wastage and plastic bottles and cups. Once microplastics enter our water systems, they remain there ending up in our drinking water – both tap and bottled.

A recent study by researchers from the University of Newcastle in Australia found that the average person consumes about 5g of plastic every week from water. The solution isn’t to switch to bottled water, however, as another study found it contains 22 times more microplastic particles than tap water and they are found in 93% of bottled water brands.

Research from the University of Victoria in Canada supports this finding. People drinking bottled water on average ingest 90,000 additional plastic particles compared to tap water drinkers each year. In addition to drinking water, microplastics can also be ingested by eating fish, shellfish, salt and beer.

Scientists suspect that microplastics pose a greater hazard to human health than previously thought. Tim Spector, professor of genetic epidemiology at King’s College London and author of The Diet Myth, has commented that he suspects microplastics will have a negative impact on the gut microbiome. As the diversity of our gut microbiome is linked with our immune health function this may have an impact on our overall health.

Animal and invitro studies have suggested negative effects on inflammation and immunity. Another consideration is that microplastic particles are able to stick to other harmful chemicals and pollutants, which may also have adverse effects on human health. However, more international and cross-disciplinary research focusing on the toxicology of these particles is urgently needed to fully understand the long-term effects on humans.

Without long-term scientific evidence it is difficult for health organizations to provide guidance on this topic. The World Health Organization published a report last year which concluded that microplastic particles in drinking water are not harmful to human health at current levels. It also acknowledged, however, that the advice was based on limited evidence and urgently called for more research and a reduction in plastic use globally.

For the time being, until further advice is provided, our water consumption should continue as normal. Currently, the level of microplastics found in both bottled and tap water are considered safe for human consumption. The type of water you drink to remain hydrated is down to individual preference. Tap water is the cheapest option, it is better for the environment and it contains less microplastics.

One option could be to filter your tap water so that it removes as much of the microplastic particles as possible. Products are available that you can add to your kitchen tap or work surface. Drinking canned water is another option but at present there are no studies comparing its microplastic content to bottled and/or tap water.

More effort to reduce the use of plastic is required both at an individual and population level. By reducing our plastic use – particularly single-use plastic – we will collectively reduce the amount that enters our environment and water systems. To help with this, always carry a portable water bottle when you are on the move.

Globally, the introduction of legislation and policies to regulate and reduce the sources and levels of plastic pollution are also warranted. Until more conclusive evidence is available, individuals should continue drinking water from their preferred source whether that be tap, bottled or filtered and focus on reducing their plastic use.