U.K. scientists said microplastics may pose even more of a threat than previously thought after confirming their presence in lung tissue taken from living people.
Microplastics were identified in all lung regions, but significantly higher levels were found in the lower lung.
The results supported inhalation as an exposure risk, according to the team from the University of Hull and Hull York Medical School (England), who said their findings could support further investigations into the effects of airborne microplastics on respiratory health.
The study, published in Science of the Total Environment, used lung tissue collected from surgical procedures on patients during routine medical care at Castle Hill Hospital in East Yorkshire.
Polypropylene and polyethylene
It found 39 microplastics in 11 of the 13 lung tissue samples tested using micro-Fourier-transform infrared (μFTIR) analysis, which the scientists said was considerably higher than results from previous laboratory tests.
Of microplastics detected, 12 polymer types were identified, of which the most common were polypropylene, (23%) polyethylene terephthalate (18%), and resin (15%). The fibers are commonly found in packaging, bottles, clothing, rope and twine manufacture, and other industries, the scientists said.
Microplastics with dimensions as small as 4 μm were found, but the scientists said they were surprised to discover samples as large as greater than 2 mm within all lung region samples, with the majority being fibrous and fragmented.
The study identified 11 microplastics in the upper part of the lung, seven in the mid part, and 21 in the lower part of the lung.
Laura Sadofsky, the study’s lead author, said: “Microplastics have previously been found in human cadaver autopsy samples. This is the first robust study to show microplastics in lungs from live people. It also shows that they are in the lower parts of the lung. Lung airways are very narrow, so no one thought they could possibly get there, but they clearly have.”
There were also considerably higher levels of microplastics found in male patients, compared with female patients.
Future investigations into health implications
“The characterization of types and levels of microplastics we have found can now inform realistic conditions for laboratory exposure experiments with the aim of determining health impacts,” said Laura Sadofsky, who is a senior lecturer in respiratory medicine in the Centre for Atherothrombotic and Metabolic Research at Hull York Medical School.
The latest investigation followed previous research by the medical school and the University of Hull, which found high levels of atmospheric microplastics within the Humber region.
That study, published in Atmosphere, identified resins, which could have originated from degraded roads, paint marking, or tire rubber, as well as polyethylene fibers.
A version of this article first appeared on Medscape UK.