In the first study of its kind, researchers in the Netherlands identified the presence of microplastic particles in human blood.

The study, published Thursday in Environment International, found a "quantifiable mass" plastic particles in the blood samples of 17 of 22 — or 80% — of the study's volunteer participants.

Microplastics are small plastic pieces less than five millimeters long. According to the National Oceanic and Atmospheric Administration, they come from a variety of sources, including from larger plastic debris that degrades into smaller and smaller pieces. Microbeads, a type of microplastic, are very tiny pieces of manufactured polyethylene plastic found in health and beauty products, such as some cleansers and toothpaste.

According to the study, the blood samples analyzed by researchers contained four high-production-volume polymers: polyethylene terephthalate (PET), polyethylene (PE) and polymers of styrene, and poly(methyl methacrylate) (PMMA).

The researchers also analyzed the samples for polypropylene but found these values were "under the limits of quantification."

PET is commonly used in food and beverage containers, including water bottles. PE is used in food packaging, bags and films (such as Saran Wrap), while PMMA, or acrylic, has applications in the human body including dental and eye implants.