Amid growing alarm over the plastic that pollutes our environment, biomedical and optics researchers at the University of Rochester are working to better understand the prevalence of microplastics in drinking water and their potential impacts on human health.
They are collaborating with SiMPore, a company that uses nanomembrane technology initially developed at the University, to devise ways to quickly filter and identify particles of plastic 5 mm or smaller in drinking water samples. They will then test the ability of these particles to cross a microscale barrier that simulates the lining of a human intestine.
"We want to see to what extent the particulates that you consume in your drinking water can pass through your gut and into your other organs," says Greg Madejski, a postdoctoral fellow in the laboratory of James McGrath, professor of biomedical engineering. Madejski is coordinating the research with the lab of Wayne Knox, professor of optics. Both McGrath and Knox are affiliated with the Materials Science Program.
Microplastics are used as ingredients in cigarette filters, textile fibers, and cleaning or personal care products. Others result when larger plastic items are worn down by sun, wind, and waves. They can be found on mountaintops and at the bottom of the oceans; in the air we breathe and in the water we drink. Exactly how many microplastics are absorbed by humans, and how much harm it is causing them has been hard to assess because the particles— below 100 microns—are so small and difficult to detect.
"These are particles that you couldn't pick up with tweezers; that you can't even see with the naked eye," Madejski says. They elude the "traditional method of skimming the surface of water with a plankton net and collecting everything," he says.
Instead the researchers will filter water through sheets of silicon nitride a hundred times thinner than the diameter of a human hair. These SiMPore nanomembranes, based on prototypes initially created in the McGrath lab, have micron-sized slits in them. "That allows us to catch micron-sized debris," Madejski says. "And because the sheets are so thin, you can filter a significant amount of water through them without a lot of pressure."