Micro and nanoplastics detectable in human tissue

Plastic pollution of soil, water and air is a global problem. Even when plastic bags or water bottles decompose to the point of no longer being an eyesore, tiny fragments can still contaminate the environment. Animals and humans can ingest the particles, with uncertain health consequences. Today, scientists report that they are among the first to examine micro and nanoplastics in human organs and tissues.

The researchers will present their results today at the American Chemical Society (ACS) Fall 2020 Virtual Meeting & Expo.

“You can find plastics contaminating the environment in virtually every place on the globe, and in a few decades we’ve gone from seeing plastic as a wonderful benefit to seeing it as a threat,” says Charles Rolsky, who presents the work at the meeting. “There is some evidence that plastic gets into our bodies, but very few studies have looked for it. And at this point, we don’t know if this plastic is just a nuisance or if it poses a danger to human health.

Scientists define microplastics as fragments of plastic that are less than 5mm, or about 0.2 inches in diameter. Nanoplastics are even smaller, with diameters less than 0.001mm. Research in wildlife and animal models has linked micro and nanoplastic exposure to infertility, inflammation, and cancer, but human health outcomes are currently unknown. Previous studies have shown that plastics can pass through the human gastrointestinal tract, but Rolsky and Varun Kelkar, who also presents the research at the meeting, wondered if the tiny particles accumulate in human organs. Rolsky and Kelkar are graduate students of Rolf Halden’s, Ph.D. lab at Arizona State University.

To find out, the researchers collaborated with Diego Mastroeni, Ph.D., to obtain samples from a large repository of brain and body tissue that was created to study neurodegenerative diseases, such as Alzheimer’s disease. The 47 samples were taken from the lungs, liver, spleen, and kidneys – four organs that may be exposed to, filter or collect microplastics. The team developed a procedure to extract plastics from samples and analyze them by μ-Raman spectrometry. The researchers also created a computer program that converted information about the number of plastic particles into units of mass and area. They plan to share the tool online so that other researchers can report their results in a standardized way. “This shared resource will help build a plastic exposure database so that we can compare exposures in organs and groups of people over time and geographic space,” says Halden.

The method allows researchers to detect dozens of types of plastic components in human tissues, including polycarbonate (PC), polyethylene terephthalate (PET) and polyethylene (PE). When combined with a previously developed mass spectrometry test, plastic contamination was detected in each sample. Bisphenol A (BPA), still used in many food containers despite health concerns, was found in all 47 human samples.

To the researchers’ knowledge, their study is the first to examine the presence of micro and nanoplastics in the human organs of individuals with a known history of environmental exposure. “The tissue donors provided detailed information about their lifestyle, diet and occupational exposures,” says Halden. “Because these donors have such well-defined histories, our study provides the first clues about the sources and potential routes of exposure to micro and nanoplastics.”

Should people be concerned about the high frequency of detection of plastic components in human tissue? “We never want to be alarmist, but there is concern that these non-biodegradable materials that are present everywhere can enter and accumulate in human tissue, and we do not know the possible health effects,” says Kelkar. “Once we get a better idea of ​​what’s in the tissues, we can conduct epidemiological studies to assess human health outcomes. This way, we can begin to understand the potential health risks, if any.