It's a Picture That Is Anything But Idyllic

Plastics don’t biodegrade, but instead break down into what is known as microplastics—objects no bigger than a pencil eraser—or into smaller particles called nanoplastics, which are invisible to the human eye. Streams and rivers, dumping the garbage into powerful ocean currents, have helped to ensure that microplastics are circulated around the globe.

“It can sometimes feel like, why should we care? That this is inevitable, and what we’re doing is a drop in the bucket in this ocean of mess,” says Dr. Rodrigues, a professor in the Department of Geography and the Environment. “But at the same time, I feel hopeful, and I think there’s something that each of us can do.”

Dr. Rodrigues is one of a number of ����ֱ�� researchers working to better understand microplastic pollution. Much is unknown, since the term “microplastics” was only coined in 2004. While the particles are known to plague aquatic and terrestrial habitats, in addition to showing up in the human body, the long-term impacts aren’t clear.

“Research is really in its infancy,” says Dr. Rodrigues, who is considering microplastic impacts not only in Philadelphia waterways but also on coral reefs. Other faculty are assessing the impacts of plastic on drinking water supplies. Still others consider the economic ramifications of finding alternatives to plastic.

She compares ongoing research to the days when 19th-century naturalist Charles Darwin traveled to the Galápagos Islands to study the region’s teeming biodiversity.

Microplastics Are a Different Kind of Animal

“Darwin was getting a handle on all of these weird and wonderful organisms, and making drawings of them,” Dr. Rodrigues says. “The types of papers that are out there right now about microplastics are very much about what they look like, their shape, their polymer, their color. There are a lot of studies out there that are trying to take it a step further. But what’s really sort of agreed upon is that this vast area of new research is in its infancy. Most studies are in the realm of the descriptive.”

While the ecological impacts of microplastics still aren’t fully understood, particles are being found in every corner of the globe, from Antarctica to tropical reefs, and in some surprising places: in human lungs, brains, breast milk and placentas. Researchers first documented small pieces of plastic in fish in 1970.

“Students are pretty shocked when they hear some of these things,” Dr. Rodrigues says. “Each year, over the last four years, I’ve had to add a new organ to the list of where we find microplastics in the human body.”

Dr. Rodrigues, for her part, has spent her career studying coral reefs in Hawaii and Puerto Rico. She started researching macroplastics—objects that are larger than a bottle cap—three years ago, and then microplastics a year ago. Headlines bespeak microplastics’ ubiquity, and Dr. Rodrigues decided she couldn’t stand by.

At ����ֱ��, she’s principal investigator of the Marine Environmental Science Laboratory, which is studying coral reef health, along with her work on macroplastics, which has grant support from the National Oceanic and Atmospheric Administration (NOAA).

Few studies exist on the long-term impacts of coral, which is an animal, ingesting microplastics, but the Environmental Protection Agency in 2021 reported that they impair coral growth in the immediate term. What is unknown are the mechanisms behind the stunted growth. Federal scientists couldn’t determine, for example, whether ingested microplastics gave the coral a sensation of fullness, or whether the materials prevented digestion of their normal zooplankton diet.

“The reason I became a scientist and a professor was to ask questions and seek answers,” Dr. Rodrigues says. “I gravitated toward coral recovery because I was fed up reading a lot of papers in which people were talking about reefs dying.”

Beyond the reefs, microplastics are seen as a broader threat to aquatic ecologies. A visit to most beaches around the world reveals as much. They are often covered with flip-flops, Styrofoam containers, fishing line and single-use water bottles. There are also ample clothing and rope, other sources of microplastic pollution due to their polyester and nylon components.

“It sometimes feels like there’s more trash than sand, and it can be overwhelming,” Dr. Rodrigues says. She does see progress, though. As part of her NOAA-funded study, local organizations and residents in Puerto Rico assisted with data collection through beach surveys, and now those same groups meet regularly for beach cleanups. “With their persistence and continued dedication, the beaches there look better than I’ve ever seen them.”

Dr. Rodrigues and Environmental Science major Brenna Bruffey ’25 CLAS recently completed a manuscript on the presence of microplastics in Puerto Rico tidal flats. Brenna was awarded a ����ֱ�� Undergraduate Research Fellowship to conduct research in the summer of 2023. She is the lead author of the paper that resulted from the research and has been submitted for publication.

Dr. Rodrigues, in the meantime, discusses microplastics in her first- and second-year Environmental Science course.

She’s made it personal and relatable for the students. Last year, students designed a study to compare liquid laundry detergent, sold in plastic jugs, with laundry sheets, which are produced without the need for plastic. The cleaning power, they found, was the same, but the sheets’ portability—and lack of plastic—gave them the edge.

“This isn’t going to solve everything, for sure, but we can be open-minded about what we can do to make a change,” Dr. Rodrigues says.

Experts Know That Change Won't Come Easily

“As I’ve gotten more interested in microplastics, I’ve asked myself, ‘Could I go a day without using plastic?’” says Kelly Good, PhD, PE, assistant professor of Civil and Environmental Engineering. “It’s very hard, maybe even impossible to do.”

Dr. Good’s professional interest centers on drinking water protection, and around her was a drumbeat of headlines about the proliferation of microplastics in aquatic settings. In 2019 came a disconcerting report from the National Institutes of Health: Fifty studies had turned up microplastics in lake water, groundwater, tap water and bottled drinking water.

“The risks microplastics pose are debated and largely unknown, but it just made me think, this is such an interesting space to be in, because there’s so much to explore,” Dr. Good says.

Her inquiries could start inside your drinking glass. Dr. Good is exploring collaborations with Pennsylvania water utilities, which have expressed interest in microplastic prevention, beginning with tapping into her knowledge in the field.

Dr. Good sees the potential for a research project, in conjunction with the ����ֱ�� Center for Resilient Water Systems, that builds on current studies of green stormwater infrastructure (GSI). Such systems manage stormwater runoff by natural processes, thereby protecting downstream water resources.

GSI systems are thought to filter microplastics and prevent them from traveling downstream to rivers, lakes and oceans. At the center, Dr. Good is working with postdoctoral scholar Erica Forgione, PhD, who is leading the effort to establish processing and analysis procedures.

“There’s already a lot of work in thinking about how these function, what their benefits are and what happens in the subsurface,” Dr. Good says. “But what plastics are coming in, what happens to them, and what else are they bringing? There are still some interesting questions to ask.”

There are troubling signs. Research has shown that microplastics can absorb toxic chemicals—including heavy metals, antibiotics and organic pollutants. A 2022 Tel Aviv University study found that microplastics concentrate toxic organic substances and increase their toxicity by a factor of 10.

Dr. Good and three ����ֱ�� colleagues—Associate Professors Steven Goldsmith, PhD, and Peleg Kremer, PhD, of the Department of Geography and the Environment; and Associate Professor Virginia Smith, PhD, of the Department of Civil and Environmental Engineering—recently received a ����ֱ�� seed grant to study the possibility of microplastics bonding with other dangerous heavy metal contaminants, such as lead.

The College of Engineering could be an important resource for others in the region doing their own microplastics investigations, such as water utilities. With access to new laboratory spaces equipped for microplastics research, there will continue to be opportunities to advance our understanding of how microplastics are moving through our watersheds.

As many as 15 large utilities around the country are looking into whether their water supplies have been infiltrated by microplastics and whether they can be removed during the water treatment process.

Dr. Good is considering her own role in the conversation.

“Can I wear more natural fibers instead of polyester?” she asks. “Can I do more thrift shopping than buying new? You have to be really intentional about trying to limit plastic. It’s truly everywhere.”

Eliminating Microplastics May Come Down to Economics

From an economist’s standpoint, it’s a basic question of economic theory, if it’s possible at all. “From a packaging perspective, the alternatives might be potentially more expensive to create,” says Chris Jeffords, PhD, associate teaching professor of Economics. “Income constraints can be a big problem, so that’s tricky. A lot of people would argue that it’s an out-of-sight, out-of-mind problem, and that because people can’t see microplastics directly, then they don’t necessarily think their contribution to the problem is having much of an impact.”

It’s hard to reach a consensus, from a policy standpoint, moving forward. Dr. Jeffords says critics have resisted legislating limits on single-use plastics. California, Colorado, New York, Oregon and Washington, DC, all have prohibitions against plastic drinking straws, for example.

“Many people lean more towards, ‘I should have the freedom to choose the straw or plastic bag I want,’” Dr. Jeffords says. “There seems to be a growing sense of personal choice in these matters, and it’s clear that environmental issues have become more polarized, even in the face of well-established scientific facts and data.”

Given the prevalence of these conversations, Dr. Jeffords plans to incorporate discussions of microplastics into his coursework, offering students a framework for considering the balance between personal choice and collective responsibility.

“Just as conversations about food, health care and housing center on the tension between individual freedoms and societal safety nets, discussions on microplastics will explore how environmental sustainability intersects with individual rights, public health and policy,” Dr. Jeffords says. “By framing these topics in terms of rights, duties and economics, students can better understand the broader implications of their choices.” ■