[ Update ] Airborne PCBs near New Bedford Harbor pose health risks, study finds

By The Standard-Times

Posted Dec 3, 2019

NEW BEDFORD — A new Boston University study shows that airborne PCBs from New Bedford Harbor may pose a health hazard for nearby residents in Acushnet, Dartmouth, Fairhaven, and New Bedford.

The levels of polychlorinated biphenyls (PCBs) in the air are high enough to affect thyroid hormones in people who live close to the harbor, raising the risk of diabetes, low birth weight, and impaired neurodevelopment, according to a news release from the Boston University School of Public Health.

Two years ago, Boston University researched showed that New Bedford Harbor was a source of airborne PCBs.

The new study, published in Science of the Total Environment, is the first to estimate the non-cancer health effects of breathing airborne PCBs around the harbor, namely thyroid hormone effects.

The U.S. Environmental Protection Agency has declared the harbor a Superfund site and has been cleaning up sediment contaminated with PCBs since the 1990s, focusing its efforts on PCB levels in the sediment and in fish consumed from the harbor, and associated cancer risks.

Asked to react to the BU study, an EPA official wrote that by far the biggest risk health risk posed by PCBs in the harbor remains the consumption of locally-caught seafood from the area closest to the sources of PCB contamination.

“The measured levels of airborne PCBs have never exceeded EPA’s health-based criteria,” the unsigned EPA statement said, and noted that the agency has been monitoring airborne PCBs in and around New Bedford Harbor since the late 1980s.

“EPA will continue to closely review our ongoing monthly air sampling results and will take action to protect public health if necessary,” the statement said.

Dr. Wendy Heiger-Bernays, a professor at the BU School of Public Health, said residents have been concerned about the air for over a decade.

“Our study shows that they are correct to be concerned,” she said in the BU release. “It also indicates that it’s important to monitor the PCBs in air as a measure of a successful cleanup.”

By request from community members, the researchers previously measured airborne PCB levels in various locations around the harbor in 2015 and 2016, including during a period of hydraulic dredging as part of the site’s cleanup. For the new study, they estimated the health effects of these measurements.

The EPA has no published guidelines for the amount of PCBs in the air that might be safe to breathe, so the BU team used evidence from other researchers’ rodent studies to develop a human-equivalent estimate of the likelihood of different levels of airborne PCB exposure to cause “unreasonable risk” as the EPA defines it.

They found that the airborne PCB levels were high enough to potentially affect the thyroid hormones of residents, particularly those living within 0.4 miles of the harbor.

“In addition to cancers, residents have been very concerned about other health problems that are not typically considered by health agencies when regulating exposures,” said Dr. Madeleine Scammell, an associate professor at the School of Public Health. “Although clean-up of the harbor is nearly complete, and some may feel this is ‘too little too late,’ we hope our results can inform other settings where inhaled PCBs are a risk, so that subtler human health risks are factored into the equation.”

The EPA statement said the federal agency agrees with one of the main conclusions of the paper regarding the harbor cleanup, which is that EPA’s Superfund cleanup “over the last ten years has actually reduced emissions of airborne PCBs.” The paper also states, “As the PCB cleanup continues and the major source of PCBs is removed, it is expected that exposures to PCBs in ambient air will decrease with time.”

According to the prepared statement, the EPA remains firmly committed to its work in New Bedford.

“We are proud that our work to dredge contaminated sediment from New Bedford Harbor is nearly complete. PCB levels in the Upper Harbor are now 100-times lower than they were previously and have been reduced to well below the cleanup level of 10 parts per million. EPA’s cleanup work has already significantly improved — and will continue to further improve — the environment around New Bedford Harbor.