EAST PROVIDENCE, R.I. (WPRI) — More than a thousand tons of microplastics live in the top two inches of sediment on Narragansett Bay’s seafloor. And that number has increased rapidly in the past 10 years, according to new research from the University of Rhode Island.

The researchers found the place with the highest concentration of microplastics was Bold Point Park in East Providence. Plastic bottles, takeout containers, and straws cover the small beach there. But scattered among the larger pieces of trash are much smaller ones, known as microplastics.

URI Graduate School of Oceanography doctoral candidate Victoria Fulfer said the tiny pieces of plastic are less than five millimeters in size, smaller than a grain of rice, and they often break down from larger chunks of plastic.

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“We mostly find polyethylene, polypropylene and polystyrene, which are making up over 70% of what we’re finding. Those are also the plastic types most commonly used in single-use plastics,” she told Target 12.

At the lab on URI’s Narragansett Bay campus, slides of microplastics cover a lab bench. Fulfer said all of them were pulled from Bold Point Park.

“This was a really disappointing site to see, because you could just look at the ground and see small bits of plastic everywhere,” Fulfer said.

It’s one of several sites she and Professor J.P. Walsh have visited over the past three years to see how widespread these microplastics are, from the shoreline to the seafloor of Narragansett Bay.

Researchers took the samples back to their lab and ran a laser over them, and were able to identify pieces of plastic using a microscope.

Walsh said while other researchers have found similar amounts of microplastics in other parts of the world, this was the first study to look at the gradient of those microplastics, from the city shorelines to the open sea.

“You go from thousands of microplastics per kilogram to hundreds,” Walsh said.

While scientists were not surprised to find the highest concentration of microplastics toward urban areas like East Providence, what was concerning was how many microplastics they found in waters surrounding more rural areas.

“The biggest surprise was higher concentrations in the southern bay on Aquidneck Island and here in Narragansett because these are areas that have lower populations,” Fulfer said.

Fulfer and Walsh’s study comes out about the same time as another research team is finding early signs that these same microplastics could pose health risks to humans, like Alzheimer’s disease and depression.

Microplastics and the body

URI Professor Jaime Ross is the principal investigator in the study at the College of Pharmacy, where they examine what microplastics do to the bodies of mice.

For three weeks, Ross said, they gave mice water containing microplastics, which was the same type used for Styrofoam takeout containers.

As a result, the researchers were able to determine microplastics are toxic to cells. But Ross said the study came with a major surprise: microplastics managed to get into the brain, despite the blood-brain barrier.

“Its function is to keep bad things out, so, viruses, bacteria,” Ross said. “And it should be selective for things like this … but here it is. That’s what we’re trying to understand, especially only after three weeks of exposure, which is really short.”

In fact, multiple pieces of microplastic made it through the barrier and were found in other parts of the mice’s bodies, like the liver. But the microscope revealed another surprise: a decrease in Glial Fibrillary Acidic Protein, more commonly known as GFAP.

“It’s been shown that in mouse models, it could lead to some forms of neurological diseases, including depression and Alzheimer’s disease,” Ross said.

While Ross wants to understand more about the potential health impacts of microplastics and what that could mean for humans, she said researchers also noticed that the mice’s behavior changed after exposure.

“They had more total movements, more anxiety-prone movements, but they also spent more time in the center of this arena where we test them,” said Ross. “Which is more akin to when we get older or we have neurological diseases.”

Research continues

Both URI teams are quick to point out that research into microplastics is still in the early stages, and there are a lot questions they want answered. For example, Ross said, we still don’t know how many microplastics humans are exposed to on a regular basis or how long microplastics stay in the body.

Yet the scientists said the research that has been conducted so far has revealed concerning results for the ecosystem and economy.

“There’s a lot of research showing negative impacts on microplastics when biota ingest them, such as fish or shellfish, and so that can impact our fisheries’ production and the food that we rely on,” Fulfer said.

Removing these tiny pieces of plastic would be nearly impossible, according to Walsh.

However, he points out, this is not the first time pollutants have entered, and he’s hopeful the damaging effects could be contained.

“That’s sort of one area of optimism of coastal storage, that the plastics will accumulate and maybe stay out of the larger marine environment,” Walsh said. “But that’s still a concern, because there’s a lot of animals who use our coastal areas.”

When it comes to making changes, Walsh said people can stop using single-use plastics like water bottles and grocery bags. He also encourages people to recycle.

Ross said making those changes is also important because it reduces everyone’s exposure to microplastics. But Walsh is also calling on public officials for broader change: “How can we encourage industry to evolve what types of plastics we’re using and what we’re doing after we use it?”

Kate Wilkinson (kwilkinson@wpri.com) is a Target 12 investigative reporter for 12 News. Connect with her on Twitter and Facebook.