Researchers have found microplastics, or tiny plastic particles, in a new location: the human blood. These ubiquitous pollutants have previously been found on the summit of Mount Everest, deep down in the Mariana Trench, and also in the faeces of babies and adults.
In a new study conducted by researchers at Vrije Universiteit Amsterdam, microplastics of sizes between 700 and 500,000 nm were found in the blood samples of around 77% of healthy participants. For size reference, 700 nm is 140 times smaller than the width of a strand of human hair.
The most common type of plastic found was polyethylene terephthalate (PET), the material used to make water bottles, which was detected in the blood of 50% of the participants. The second most common was polymerized styrene (PS), mainly used for food packaging. PS was found in 36% of participants.
Plastic particles can enter our bodies through the air, water, and food. Exposure routes include mucosal contact through ingestion or inhalation and dermal uptake via damaged skin. It can also be accidentally ingested when using personal care products, such as lip gloss and toothpaste. Other sources of plastic intake include polymeric implants, dental polymers, and tattoo ink residues. This shows how extensive potential exposure routes are – so will we ever be safe from this material that was first synthesised over a century ago?
Plastics’ biological fate remains uncertain, and further study needs to be done to answer the long list of pressing questions. Bioaccumulation of polystyrene microparticles has been observed in mice liver, kidney, and gut after oral administration – will this retention and accumulation occur in humans too? How exactly do the plastics’ size, shape, charge and composition affect their fates?
We use polymeric nanosized carriers to deliver drugs across the blood-brain barrier – can microplastics pass through the blood-brain barrier too? Will it consequently cause irreversible damage to the brain? How long will these plastics reside in the bloodstream? Can plastics be eliminated from the body via filtration or excretion? How much more likely are occupationally exposed workers to experience plastic-induced health risks than the general population?
Shockingly, microplastics have already been found in the placenta of microplastics in human blood unborn babies, detected on both the foetal and maternal sides of the membrane. The plastics found originated from packaging, cosmetics and personal care products. This study by researchers at San Giovanni Calibita Fatebenefratelli Hospital, Italy, provides further evidence for the hypothesis that plastic particles can be transported to organs, and through to the foetus, via the bloodstream. It is unknown whether the plastics entered the babies’ bodies. Concerns of this discovery include effects on foetal growth and immune development.
Shrinking down to nanoplastics, these smaller cousins of microplastics in human blood believed to have the potential to cause cancer development, growth and metastasis. Through experiments involving nanoparticles, we can theorise that nanoplastics can translocate to organs far more frequently, through the lymphatic and vascular systems.
We can also speculate that nanoplastics of less than 100 nm can overcome physiological barriers through hijacking intestinal routes. This could allow nanoplastics to play a role in the pathogenesis of gastrointestinal cancers. In fact, many studies have provided evidence for nanoplastics’ association with various carcinogenesis biochemical events that make up the ‘Hallmarks of Cancer’. These events include genetic alterations, DNA fragmentation, membrane damage, and even cytotoxicity.
With plastic production set to double by 2040 and plastic producers wanting to invest £2.3 trillion into making more plastic, the founder of the Common Seas Charity, Jo Royle, says that we are all entitled to know the impact of plastics on our bodies. The charity, along with scientists, MPs, and over 80 other non-government organisations are petitioning for the UK government to allocate £15 million, from an existing research-and-development fund, towards urgent research on the human health impacts of plastics.
The emerging field of ‘medical polymer science’ allows scientists from different fields to combine forces and improve our understanding on the interaction between us and plastics. A recent review cleverly stated that what the 1950s media praised as ‘matter plastic’ is now a ‘plastic matter’. As residents of this planet, we should all play our parts and contribute to minimising the impact of plastics on nature, and ourselves.
Source: This new is originally published by palatinate.org.uk