Microplastics are specks of plastic. By definition, they are less than 5mm in any dimension, but many are invisible to the naked eye. There are two types of microplastics: primary microplastics and secondary microplastics. The former are the particles used in some cosmetics, and the latter comes from the breakdown products of larger plastic items.
Much concern about microplastics has previously focused on their effect on the marine environment, as they are found in oceans worldwide. Many marine organisms, such as fish and shellfish, have been found to contain microplastics
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A recent study looked for particles that could be absorbed across membranes in the human body. They filtered the blood to collect any plastic particles between 700 nanometers(nm) and 500,000nm. To avoid any plastic contamination, the researchers used glass fiber filters.
The researchers looked for five common plastics:
poly(methyl methylacrylate) (PMMA), used in dentistry and other medical applications
polypropylene (PP), commonly used for packaging and textiles
polymerized styrene (PS), used for lightweight packaging
polyethylene (PE), the most widely used plastic, used for carrier bags, among many other things
polyethylene terephthalate (PET), widely used in textiles and food and drink containers
The samples from the filters were processed by double-shot pyrolysis to produce chromatograms from which scientists could identify the contents.
“Human biomonitoring methods for measuring plastics additives have been available for several years […] But measuring microplastics, especially at the small size that would likely circulate in blood vessels (<7 microns), is very hard,” Prof. Galloway told Medical News Today.
“This paper is good news because it describes a method that is sensitive enough to do this in blood samples and combines size fractionation and mass measurements,” she added.
More than three-quarters of the blood samples contained a quantifiable mass of plastic particles.
The researchers found PET — which most drinks bottles are made from — in the blood of more than half of those tested. They did not detect PP in any of the samples.
Researchers found at least 3 different types of plastic in some blood samples.
Prof. Galloway was unsurprised by the findings:
“The fact that just about everyone has microplastic in their blood isn’t so surprising when you consider that just about everyone has plastics additives in their bodies.”
The researchers suggest several ways the plastics may have entered the bloodstream — via air, food, water, personal care products such as toothpaste and lip gloss, dental polymers, and tattoo ink residues. What happens to the microplastics once they enter the bloodstream is unclear.
In vitro studies have shown the effects of microplastics on cells. A recent study in Germany found that microplastic particles can destabilize lipid membranes — the barriers that surround all cells — which may affect their functioning. Another study found that microplastics had many effects on cells, including cell death.
What effect they might have on organs is, as yet, unknown.
