A team of Dutch scientists have found evidence of plastic particle pollution in human blood for the first time.

Scientists already know people ingest the particles, which have been found in faeces and the placenta, but their presence in the blood had proved elusive until now.

Researchers at Amsterdam’s VU University used special glass tools to carry out the research, to avoid the results being skewed by plastic research equipment.

They looked at 22 trial participants, and found plastic particles in the blood of 17. Half of the samples contained PET, a type of polyester used to make plastic bottles. In a third of cases they found polystyrene, a packaging material often used for food.

Microplastics, up to 5 mm in size, are a result of the deterioration of plastic waste and have been found everywhere in the environment.

The particles that the scientists were able to detect in the blood are much smaller and measured between 700 nanometre and half a millimetre.

It is unclear, as yet, how much damage the particles can do to the human body but their presence alone is worrying, head researcher Marja Lamoree told broadcaster NOS. ‘You can compare it to seeing an polar bear from a boat. It can do you no harm but go nearer and you will find yourself in trouble.’

Lab studies have indicated that that microplastics may damage human cells but whether or not that would be the case in practice would depend on how long the particles remain in the body.

‘Further studies will have to be carried out,’ Lamoree said. ‘Every result brings up ten new questions. Perhaps the particles leave the body via the kidneys, or maybe they accumulate in or around the organs. We will have to see if the people that were found to have particles in their blood still have as many in a year’s time.’