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MIT Better World

By Kris Willcox

Field research has brought Moala Bannavti, a postdoctoral fellow in the Department of Civil and Environmental Engineering, to locations ranging from public school classrooms in Iowa to the tops of dams along New England’s Neponset River.

Bannavti investigates air-borne levels of polychlorinated biphenyls (PCBs), a now-banned group of man-made, organic chemicals known for their toxicity and persistence in the environment. Classed within the larger category of “forever chemicals,” PCBs were once widely used in manufacturing and have been linked to a wide range of adverse health effects, from skin lesions and breathing problems to cancer and neurotoxicity. Researchers continue to investigate PCB contamination in soil, food, drinking water, and other exposure routes to better understand exactly how and where people come into contact with these chemicals.

New era of PCB research

In 2022, Bannavti was awarded a fellowship through the MIT Postdoctoral Fellowship Program for Engineering Excellence to expand her work in a new sphere of PCB research: exposure through the air we breathe. “For decades, we’ve been talking about known routes of PCB exposure like food, maternal exposure, or drinking water,” she says, but more recent studies have demonstrated that inhalation is also a significant, though incompletely understood, route of exposure. “Now we’re having a whole new conversation about the impact of breathing in PCBs.”

The work of remediation can be costly, she notes, and the heaviest burdens of exposure to environmental pollution are often borne by marginalized and low-income communities. An underlying goal of all her work, Bannavti says, is “the pursuit of environmental justice,” which includes making remediation of pollutants like PCBs accessible to all communities and providing individuals and policymakers with the information needed to advocate for change.

Bannavti is advised by Philip Gschwend, professor emeritus, Department of Civil and Environmental Engineering, and Noelle Selin, professor in the Department of Earth, Atmospheric and Planetary Sciences, interim director of the Institute for Data, Systems, and Society, and director of the Technology and Policy Program. In addition to her MIT colleagues, Bannavti is partnering with researchers and staff at the Massachusetts Department of Environmental Conservation and the US Environmental Protection Agency.

“I’m a proud HBCU [Historically Black Colleges and Universities] grad,” says Bannavti, who received her BS in natural resources at Delaware State University and earned a doctorate in civil and environmental engineering from the University of Iowa, where she studied PCB air contamination in a minority-predominant, low-income public school. She is pleased that her MIT fellowship program encourages applicants from underserved backgrounds.

A superfund site close to campus

Bannavti’s postdoctoral research is the first to specifically examine PCB air contamination at the Lower Neponset River Superfund Site, a 3.7-mile stretch of river flowing through several densely populated communities in greater Boston, including Dorchester and Milton. “Getting onto the dams is scary at first, but it’s cool,” she says. To measure airborne PCB levels, Bannavti places strips of polyethylene material that have been prepared for passive sampling on railings at the top of the dams. These are left for about a month, then brought back to the lab for analysis.

“When I was looking at PCBs in public schools,” Bannavti explains, “some remediation efforts had already started, so my work was about adding to our understanding of the characterization of PCBs in different parts of the school and how they move around in those spaces. Here at the Neponset, we’re starting much closer to the beginning of the research timeline.” In time, she and other researchers can build a more complete picture of PCB emissions in and around the Lower Neponset River. “It all begins with these initial measurements,” she adds, “which provide a jumping-off point for policy decisions and community education and for more research about this site and others like it.”

Moving forward with an eye to equitable remediation

Whether the setting is a public school classroom or a dam along an urban riverway, Bannavti’s work is motivated by an underlying commitment to environmental justice and to empowering individuals and communities with information. “People care about what they are breathing in,” she says. “They realize there may be harm from these chemicals, and they deserve to know what their exposure is.” Bannavti hopes that her findings will inform future research, remediation efforts, environmental policy, and community action.

“Our job as researchers and academics,” she says, “is to think about what new tools we can engineer to make the remediation of PCBs, and all forever chemicals, more equitable.”