Sediment contaminated with polychlorinated biphenyls, or PCBs, from the bottom of New Bedford Harbor is the number-one source of airborne PCBs in the neighborhoods surrounding the port, according to a new study by researchers from the Boston University School of Public Health (SPH) and the University of Iowa.
In fact, airborne PCB emissions are so high that researchers say the harbor is the single largest continuous source of airborne PCBs ever measured from natural waters in the US or Canada. The study appears in Environmental Science & Technology Letters.
The harbor is one of the largest PCB Superfund sites in the nation, currently undergoing cleanup. The US Environmental Protection Agency (EPA) has monitored airborne PCB levels near the harbor since 1999. The levels measured in the study are consistent with levels measured by the EPA, but this is the first time that researchers have focused on the harbor as a unique source of airborne PCBs.
Residents have been concerned with air quality since dredging to clean the port started in 1994. Industry in the area used PCBs to produce electronic devices from 1940 until the late 1970s, when the EPA banned the manufacture of PCBs due to health concerns.
“As our knowledge grew about the high levels of PCBs in the sediments and water, we began to question the air from this site,” says Karen Vilandry, president of the community-based group Hands Across the River Coalition (HARC).
Wendy Heiger-Bernays, BU associate professor of environmental health, says the New Bedford-area community requested the study and “played an integral role in its completion.”
Researchers used calculated emissions and atmospheric dispersion modeling to confirm New Bedford Harbor as the source of airborne PCBs. PCBs are released from the sludge at the bottom of the port and escape into the water and air.
The research team worked with residents affiliated with HARC to select air-sampling locations at 18 sites in New Bedford, Fairhaven, Dartmouth, and Acushnet. Air samples were taken during three consecutive periods from July to November 2015. The highest readings for airborne PCBs were from sampling locations closest to the harbor.
PCBs can cause a variety of adverse health effects, including an increased risk for cancer in humans. The effects of long-term inhalation of airborne PCBs are still unknown.
Keri Hornbuckle, professor of civil and environmental engineering at IIHR—Hydroscience & Engineering at the University of Iowa and core leader of the Iowa Superfund Research Program, says the study shows that PCBs are coming from the harbor and “not from a variety of sources.” Lead author Andres Martinez, a research scientist at IIHR—Hydroscience & Engineering, says there is more work to be done to pinpoint the sources of PCBs.
Community engagement in the study was assisted by Alternatives for Community & Environment and the Toxics Action Center (TAC).
“Every time we went to collect the monitors from residents’ homes, we were faced with the same question: ‘Should I be worried?'” says Claire Miller of TAC. “Exposure is a 24/7 reality for folks living near the harbor, and this study is an important step forward.”
Co-authors from SPH include Madeleine Scammell, assistant professor of environmental health, and Kathryn Tomsho and Komal Basra of the BU Superfund Research Program.
A version of this article was originally published in BU School of Public Health.