Micro plastic particles have been found in human blood for the first time, a study showed, cautioning that microplastics may be transported to organs via the bloodstream.

17 out of 22 healthy volunteers carried quantifiable amounts of plastic particles in their blood, according to the study published by Amsterdam-based peer-reviewed journal Environment International.

The study, funded by non-profit Common Seas and the Dutch National Organisation for Health Research and Development, measured plastic particles as small as 700 nanometres in human blood. (1 nanometre is equal to one billionth of a metre)

The study results support the hypothesis that human exposure to plastic particles results in absorption of particles into the bloodstream. This indicates that at least some of the plastic particles humans come in contact with can be bioavailable and that the rate of elimination via e.g. the biliary tract, kidney or transfer to and deposition in organs is slower than the rate of absorption into the blood.

It focused on five high production volume polymers including polyethylene terephthalate (PET) which is used in bottles.

Microplastics are ubiquitous pollutants in the living environment and food chain but no study to date has reported on the internal exposure of plastic particles in human blood.

An understanding of the exposure of these substances in humans and the associated hazard of such exposure is needed to determine whether or not plastic particle exposure is a public health risk, scientists said.

Over 300 million tons of plastic are produced every year, half of which is used to create single-use items such as shopping bags, cups and straws, according to the International Union for Conservation of Nature (IUCN).

At least 14 million tons of plastic end up in the ocean every year, says IUCN. "Plastic debris is currently the most abundant type of litter in the ocean, making up 80% of all marine debris found from surface waters to deep-sea sediments. Plastic is found on the shorelines of every continent, with more plastic waste found near popular tourist destinations and densely populated areas."

The main sources of plastic debris found in the ocean are land-based, coming from urban and stormwater runoff, sewer overflows, littering, inadequate waste disposal and management, industrial activities, tyre abrasion, construction and illegal dumping. Ocean-based plastic pollution originates primarily from the fishing industry, nautical activities and aquaculture.

Under the influence of solar UV radiation, wind, currents and other natural factors, plastic breaks down into small particles called microplastics (particles smaller than 5 mm) or nanoplastics (particles smaller than 100 nm). The small size makes them easy for marine life to ingest accidentally.

Studies reporting the presence of microplastics in treated tap and bottled water have raised questions and concerns about the impact that microplastics in drinking-water might have on human health.

The World Health Organization (WHO) had earlier called for a further assessment of microplastics in the environment and their potential impacts on human health.

Microplastics larger than 150 micrometres are not likely to be absorbed in the human body and uptake of smaller particles is expected to be limited, the UN health body had said.

Wastewater treatment can remove more than 90% of microplastics from wastewater, with the highest removal coming from tertiary treatment such as filtration, according to WHO. "Conventional drinking-water treatment can remove particles smaller than a micrometre."

polyethylene

Plastic particles found in human blood for first time