A unique collaboration between university and community led to an important study evaluating the human health risks posed by airborne polychlorinated biphenyls (PCBs) coming from sediment in the New Bedford Harbor in Massachusetts. Researchers from Boston University found that the harbor, the home of one of the largest PCBs Superfund sites in the country, is the primary source of PCBs in the air around the harbor. They described the harbor as the “largest reported continuous source of airborne PCBs from natural waters in North America.”
The study found that PCB levels in the ambient air were highest closest to the harbor and that changes in thyroid levels are more likely to occur among people who live near the harbor compared to residents who live further away. These researchers focused on the non-cancer risks posed by exposure to PCBs rather than the cancer risks which EPA used to drive its decisions on the cleanup of the harbor which has been ongoing since the 1990s. So far, more than 425,000 cubic yards of PCB-contaminated sediment has been removed from the harbor as of December 2017 according to the EPA. Much of this waste has been placed in a constructed landfill in the harbor. The local group, Hands Across the River, has been fighting to stop the agency from doing this for years.
In response to requests from residents to monitor the ambient outdoor air for PCBs in places where they live, researchers from Boston University partnered with the Toxic Action Center, the University of Iowa and local residents to identify locations and design a monitoring program to meet community needs. In contrast, EPA selected monitoring locations for convenience or where concentrations were expected to be the highest.
The researchers modeled the data they collected and for the first time were able to estimate residential exposures and health risks for residents living around the harbor. They chose the thyroid as a target of PCB toxicity based on strong evidence in human and animal studies in the scientific literature. They compared thyroid changes in residents and PCB levels in the ambient air near and distant from the harbor and were able to show potential health risks associated with proximity to the PCB contaminated Superfund site in the New Bedford Harbor.
EPA’s response to these findings in part was to say that “the measured levels of airborne PCBs have never exceeded EPA’s health-based criteria.” This of course misses the point that this study identified new health risks beyond what the agency had previously considered. EPA’s standard risk procedures do not capture all health risks. Their focus was on cancer risk. This study focused on non-cancer health risks.
It has long been suspected that PCBs in the sediment of rivers and waterways will evaporate to some degree and eventually become airborne, but industry and government have pushed back arguing that PCBs do not substantially volatilize and if they did, their impact would be insignificant. This study puts that argument to rest.
This study is a remarkable example of what scientists and researchers can do together to address community needs. Scientific information is a powerful tool when university expertise and resources are focused on responding to community concerns. In this collaboration, new risks were identified that EPA had not previously considered. More of these collaborations are needed.
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