Ordinary Lab Gloves May Have Skewed Microplastic Data

Scientists researching the microplastics crisis may have unintentionally made it worse. Not by directly contributing to the problem, but by inadvertently skewing the data. The culprit, a new study published in the journal RSC Analytical Methods reveals, could be their gloves.

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A team of researchers from the University of Michigan discovered that nitrile and latex gloves traditionally worn by laboratory scientists of all stripes, can shed particles called “stearates” that mimic microplastics. These hydrocarbons, added by the glove manufacturers to prevent the gloves from sticking to the molds, can fool spectroscopy machines and are nearly impossible to distinguish from polyethylene under electron microscopes.

The discovery of the problem was something of an accident itself. Researching microplastics in the atmosphere, study author Madeline Clough detected alarmingly high levels of the tiny pollutants on a metal substrate she prepared while wearing nitrile gloves, a practice the literature currently recommends.

Read more: “A Plastic Oasis in the Sea”

“It led to a wild goose chase of trying to figure out where this contamination could possibly have come from, because we just knew this number was far too high to be correct,” Clough said in a statement. “Throughout the process of figuring it out—was it a plastic squirt bottle, was it particles in the atmosphere of the lab where I was preparing the substrates—we finally traced it down to gloves.”

Previous research found that disposable gloves used in wet preparations of samples could skew microplastics data, but this is the first study to find similar activity in dry preparations.

So what’s the solution?

The researchers tested seven different glove types, painstakingly examining every imaginable point of contact between a gloved hand and a piece of laboratory equipment. They found that, on average, all gloves led to about 2,000 false positives per millimeter squared of contact area. Clean-room gloves, manufactured without stearites, led to only 100 false positives per millimeter squared of contact area, making them the safer bet if gloves need to be worn for a procedure.

Most importantly, the researchers stress this doesn’t mean there’s no such thing as microplastic pollution, just that scientists studying it should refine their methodology. “We may be overestimating microplastics,” study co-author Anne McNeil said. “But there’s still a lot out there, and that’s the problem.”

It’s a difficult thing for scientists to get their hands around. Now they just need to be a little more mindful of what those hands are wearing.

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