Two University of Rhode Island researchers conducted a first-of-its kind study on microplastics in Narragansett Bay — one that found “extensive” microplastic storage along the top 2 inches of the Bay’s seafloor. The study was published in Scientific Reports earlier this summer.
“I was definitely surprised by how high the microplastic contamination was, particularly up near Providence,” said Victoria Fulfer, co-author of the study and doctoral candidate at URI’s Graduate School of Oceanography. “I figured that we would see higher contamination near the urban areas, but some of our numbers were much higher than previously reported for other coastal environments, so I was shocked by that.”
Microplastics are small plastic particles that are 5 centimeters or smaller — the smallest of which can’t be seen without a microscope.
The study found more than 16 trillion microplastic particles weighing more than 1,000 tons were stored in surface sediments from the Bay, buildup from over the last 10 to 20 years. The study’s findings highlight that estuaries may serve as “a significant filter for plastic pollution,” and the high concentration of microplastics may have negative consequences for Rhode Island’s ecosystems.
Fulfer conducted the research alongside J.P. Walsh, professor of oceanography and director URI’s Coastal Resources Center.
“The design of the study was to look across the system from city to open ocean and to sample the coastline as well as the intertidal zone, the sub-tidal areas, and the seabed,” Walsh said. “It wasn’t a surprise to see high levels of plastic near the city, but to see them so spread out throughout the system — both from the shoreline to the seabed — I think was quite a surprise for us.”
Fulfer and Walsh began collecting shoreline and sediment samples throughout Narragansett Bay in the fall of 2020. Fulfer took the lead on analysis of samples, extracting the microplastics, and measuring them using “sophisticated state-of-the-art methods,” Walsh said.
“Sometimes they’ll look like flakes, particles, or fragments of all different colors, and sometimes they’re bead-shaped,” Fulfer said. “But once they are that small, it’s difficult to tell what they were when they were bigger, which is sort of the challenge of microplastics research.”
There are many ways microplastics end up in Narragansett Bay, including runoff, littering of single-use plastics, wastewater treatment facilities, shipping, industrial plastic production, and fisheries, according to the study. It is estimated that only 1 percent of marine plastic remains in the water column, and that most microplastics are eventually deposited on the shorelines and in marine sediment.
Current research suggests microplastics in the environment have negative impacts on marine life and ecology, and potentially on human health, too.
“There’s a lot of research that’s come out in recent years showing that [microplastics] have negative impacts on the growth of a lot of organisms like fish and shellfish that we find all over the Bay,” Fulfer said, adding that there could be negative consequences for local fisheries.
“In terms of humans,” Fulfer continued, “there’s less research about the negative consequences, but there definitely is concern, both because research says we are finding [microplastics] in all human tissue and because microplastics contain chemicals that could increase the negative impacts that they have on wildlife and on people.”
A new study published Wednesday by the University of Rhode Island found that microplastics may “infiltrate all systems of the body” and “cause behavior changes” in mammals. The study, conducted by URI professor Jaime Ross, exposed mice to varying levels of microplastics in drinking water over the course of three weeks. The study found that microplastic exposure induced “both behavioral changes and alterations in immune markers in liver and brain tissues.” The mice subjects “began to move and behave peculiarly, exhibiting behaviors akin to dementia in humans,” the study said.
Fulfer and Walsh’s research presents an opportunity for Rhode Island to be proactive in addressing the Bay’s high concentration of microplastics.
“Since the estuary is trapping a lot of these microplastics before they make it into the open ocean, that means that we do have the potential to clean them up,” Fulfer said. “We can implement control measures from the land to reduce the amount getting into the rivers and then into the Bay.”
The study notes that when it comes to cleaning up the concentration of multiplastics, “some efforts have focused on the water column, but more work is needed along the estuarine shorelines and seabed.” The study also suggests that dredged material should be carefully monitored to limit the reintroduction of plastics, as dredged material had particularly high concentrations of microplastics.
Fulfer and Walsh suggested ways people can do their part, like reducing and refusing single-use plastics whenever possible.
“You hear about reduce, reuse, recycle, I think the ‘refuse’ is one thing that we don’t discuss enough,” Walsh said. “Just try not to accept plastic. If you don’t need a straw or you don’t need an extra spoon, don’t take it. Think about the second life of things.”
Picking up litter on the side of the road or at the beach is another thing people can do to help.
“Even things that are a mile or more from the shoreline could still make it into the estuary from runoff on all the roads,” Fulfer said.
Fulfer also commented on the potential for policy. “Here in Rhode Island, especially since we do have a smaller state where it’s a little bit easier to pass these kinds of overarching mitigation policies,” she said.
Narragansett Bay contains 700 billion gallons of water across 150 square miles. It is considered Rhode Island’s greatest natural resource, and has a dense urban population. Its pollution history dates back to the Industrial Revolution, when development began in and around Providence.
“Today, plastic pollution is an increasing concern as it is apparent during any visit to the Bay, and like other estuaries, it poses an unknown threat to the ecosystem including micro- and macro-organisms and humans that consume seafood from the system,” the study said. “In sum, this first system-wide study of estuarine sediments demonstrates extensive trapping of [microplastics], providing additional evidence that coasts bear additional burden of high microplastics.
These observations indicate significant and far-reaching ecosystem consequences, but they also offer an opportunity for more efficient plastic removal to help limit broader impact on the ocean.”