The widespread prevalence of microplastics throughout the human body is indisputable but the potential health risks remain unknown, according to University of Rhode Island scientists.
Researchers Jyothi Menon, Jaime Ross and J.P. Walsh participated in a panel discussion on Aug. 21 about plastic pollution moderated by “Rhode Island PBS Weekly” reporter Michelle San Miguel. About 70 people attended the forum at Avedisian Hall to learn how plastic pollution is harming water bodies and the implications that microplastics could have on human health.
Sharing Their Research
Walsh, a professor of oceanography, described his efforts to measure microplastics on the shoreline and seabed of Narragansett Bay. Last year, Walsh and his team published a study that found the floor of Narragansett Bay contains more than 1,000 tons of microplastics and that buildup has occurred in the last 10 to 20 years.
“There’s not a lot of action in trying to rectify the problem,” Walsh said.
He worries about how the base of the food web is being affected by microplastics, which are mistaking the small particles for food. And, he said, bodies of water are far from the only place infiltrated with microplastics.
“We’ve measured microplastics and seen microplastics from mountaintop to deep ocean floor,” Walsh said. “So it is a truly global problem that is not going away.”
Ross, an assistant professor of neuroscience and pharmaceutical sciences, shared how she and her team exposed mice young and old to drinking water over three weeks. After observing them in an open field, they found ingesting microplastics caused the mice to have changes in their behavior akin to dementia in humans.
Research published in the National Library of Medicine has shown the mouse genome shows many disease genes shared with humans.
Her discoveries have prompted Ross to do more research on Alzheimer’s disease with the hope of determining whether microplastics are contributing to the disease.
“We’re running several studies in the lab and both of them are involving looking at the intersection between genetic risk factors for developing Alzheimer’s disease that we all may have as humans and that intersection with microplastic exposure,” she said. “And what are the outcomes?”
About half of the microplastics humans consume end up in the liver, according to Menon, an associate professor in the Department of Biomedical and Pharmaceutical Sciences.
“The liver is a clearance organ,” she said. “Anything that goes into the body passes through the liver at some point.”
Menon exposed human liver cells to three sizes of microplastics. “What we see is that there is a dose-dependent and a size-dependent toxicity,” Menon said. “So the smaller your particles are, the greater the toxicity on the cells.”
The Great Unknown
Plastic generation has been growing exponentially in the United States for decades. In 1960, the United States generated 390,000 tons of plastic, according to the Environmental Protection Agency. In 2018, plastics generation was 35.7 million tons. Despite the growth in plastic consumption, little is known about the health effects.
“I think that part of the problem is that we really thought for a long time that plastics were inert, meaning not harmful,” Ross said. “They were akin to glass, maybe even metal. They could be harnessed for so many different applications. I think that’s what we thought.”
“We just have so much more (plastic) in our environment now because we’re producing so much more. And over time that small percentage of mismanaged waste is increasing in our environment,” Walsh said. “Now the questions are what are the impacts and what are the concentrations in the environment, in our bodies, and at what levels do those concentrations, meaning how much is there in a given volume or mass, is going to have an impact on an organism, whether it’s a very small organism in the ocean or it’s us.”
Scientists Change How They Use Plastic
All three panelists said they have made changes in their daily lives to reduce their dependence on plastic. Menon said she no longer microwaves food wrapped in plastic, like frozen vegetables. She said she does her best to wear clothes made from cotton and tries to avoid fabrics made from plastic, such as polyester and nylon.
“Even things like bedsheets and pillow covers, I personally feel if I’m using a polystyrene or microfiber-based pillow covers and you’re sleeping on that throughout the night, you have more risk of perhaps even inhaling some of this,” Menon said. “So I try to avoid things like that.”
Ross encouraged people to walk through their day and consider their plastic use.
“Think about how you prepare your food, how you make your coffee, what kind of tea bags maybe you use or don’t use, how your food is stored,” she said. “Are you microwaving food in plastic?”
Walsh said he thinks a lot about how humans use plastic while they eat and drink. He said he always uses glass containers and tries to avoid wrapping food in plastic.
The “Rhode Island PBS Weekly” segment “Green Seeker: Plastic Pollution,” was screened at the event. You can read more about the piece here.
