In what they describe as a “pioneering biomonitoring study”, Dutch scientists have for the first time identified plastic particles in human blood.
What had previously been known was that humans ingested microplastics in various forms and various ways, including the food we eat and the air we breathe – all adding up to about five grams of plastic a week, according to a 2019 study by the World Wildlife Fund.
Those microplastics – roughly the weight of a plastic credit card every week, says the WWF – have been identified in human faeces and even, using microspectroscopy, in human placentas, but never before in the blood itself.
The research by a team from the Free University in Amsterdam, published in the journal, Environment International, analysed blood samples from 22 people and found plastic particles in the bloodstreams of 17 of them.
Half of the samples contained the most common plastic of its type, polyethylene terephthalate or PET, a type of polyester used in plastic bottles, plastic bags and clothes. In a third of the samples, the researchers found polystyrene, widely used in food packaging.
Accumulation in organs
"It's unclear yet how much damage these microplastics can do to the human body but their presence alone is worrying," said lead researcher Prof Marja Lamoree.
“Now that we’ve identified them in the bloodstream, we have a starting point. Perhaps they will leave the body via the kidneys or perhaps they will accumulate in or around the organs. We will have to see what has happened in, say, a year’s time.”
Research in the UK has shown that microplastics in the quantities known to be eaten by people in their food do cause damage to human cells in laboratory tests, causing allergic reactions, damage to the cell walls and even cell death.
Whether that will be borne out in practice might depend, for example, on how long the microplastics remained in the body before they were excreted, said Prof Lamoree.
Public health
“This research must now be expanded to determine whether we can say that, broadly speaking, exposure to plastic particles poses a threat to public health.”
Microplastics are generally defined as less than 5mm in size, but because of advances in technology the Dutch scientists were able to detect particles as small as 700 nanometres thick. A human hair, for example, is typically around 40,000 nm thick.
So delicate was the measurement process that the Amsterdam team had special glass containers made to remove the possibility that plastic containers could interfere with the results.
Swedish environmental entrepreneur Bengt Rittri said the findings showed the urgent need for governments to tackle microplastic pollution. The endocrine system-disrupting chemicals they contained, he maintained, were the "number one threat to humankind".
