Last updated: April 17, 2024
From the deck of our Casco Baykeeper boat R/V Joseph E. Payne, science staff from our organization and Bigelow Laboratory for Ocean Sciences collected more than 150+ PFAS samples at 21 sites across Casco Bay in 2023.
This is the most complete dataset yet of the concentrations of PFAS pollutants, so-called forever chemicals, in the waters of Casco Bay. Their results show widespread — but not alarming — levels of several of these chemicals across the region, highlighting the need for more research into the sources of PFAS and their possible impacts on the marine environment.
The first step in monitoring PFAS in Casco Bay
The results of this effort mark the first step of a multi-year, collaborative project to provide much-needed information on sources of these toxic chemicals and impacts to the coastal environment.
PFAS, which stands for per-and polyfluoroalkyl substances, have received significant attention in recent years, particularly in Maine. The state has emerged as a national leader in monitoring and regulating this persistent and commonly-used family of chemicals. However, until now, little had been done to track PFAS levels in Casco Bay’s marine waters.
A dynamic partnership
The latest results are the first phase of a multi-year study led by Bigelow Laboratory Senior Research Scientist Christoph Aeppli, Ph.D., in collaboration with Friends of Casco Bay staff. In 2023, the team collected water samples at Friends of Casco Bay’s seasonal monitoring sites. This year, the team plans to build upon this preliminary dataset to better understand the primary sources of PFAS into Casco Bay’s water and coastal sediment. That information, in turn, will help state agencies protect local water quality and respond to potential changes in federal regulations.
“We are delighted to partner with Bigelow Laboratory and their top-notch scientists,” says Casco Baykeeper Ivy Frignoca. “The data we are collecting will complement existing monitoring of shellfish and fish tissues and discharges from wastewater treatment plants to give us a more complete understanding of PFAS levels in the Bay and whether there are areas that pose risks to the health of our waters and to people.”
As Dr. Aeppli notes, “PFAS compounds can travel through water, and we clearly have many different pathways for these chemicals to enter our waterways and flow into the estuary, including both small but powerful sources and widespread, diffuse sources.” Ivy offers, “Based on one year of study with six sampling events, we did not find alarming levels of certain PFAS compounds and cannot yet draw any conclusions from these results.” This year’s follow-up study will hone in on potential land-based sources.
Low levels of PFAS found at all sites
PFAS were detected at all of the study’s monitoring sites. While there are no safe limits set for marine waters, all of our samples were lower than Maine’s interim drinking water standards. [Update on 4/17/24: The EPA finalized new and more stringent standards for drinking water on April 9, 2024. We understand that drinking water regulations are not the best framework to compare to marine waters since we don’t drink bay water. We are discussing how to evaluate the 2023 PFAS results and hope this continued study will help inform setting standards for PFAS in marine waters.]The levels appeared to dilute as offshore measurements were lower than those closer to shore.
The study did find elevated levels close to known sources, including the Brunswick Naval Air Station, an EPA Superfund site since 1987. Those levels decreased quickly further offshore. Levels were comparatively low in the waters around the heavily urbanized Portland area.
“Before, we didn’t even know how much PFAS there was or how long it takes to dilute in the water, and now we’ve identified some clear patterns across Casco Bay,” Dr. Aeppli said. “We can use that insight to begin a more in-depth study on the contributions of individual sources.”
The 2023 study was funded by Maine Sea Grant. All the samples were processed in Dr. Aeppli’s lab at Bigelow with a method capable of detecting 40 different PFAS compounds at concentrations akin to a single pinch of salt in a swimming pool.
The next phase will look at specific sources of PFAS
With a better understanding of the basic distribution and levels of PFAS across Casco Bay, Friends of Casco Bay and Bigelow Laboratory can now begin to focus on identifying the contributions of specific sources. They will also sample sediments to understand how these chemicals are accumulating in the near-shore environment. These efforts, which will continue through 2025, are supported, in part, by funding from the federal Environmental Protection Agency.
Conversations with the public about PFAS
Casco Baykeeper Ivy Frignoca and Science and Advocacy Associate Heather Kenyon are leading a stakeholder process to discuss results and hone the selection of monitoring sites for further study. The stakeholders include experts working across fields such as wastewater and stormwater management and shellfish health.
“We are grateful for Bigelow Laboratory’s leadership and partnership,” said Executive Director Will Everitt. “By working together with Chris Aeppli and his team this year, we can do a deeper dive into how PFAS may be getting into the Bay and work with decision-makers about what actions we collectively have to take to protect our coastal waters.”
Learn more by watching our Coffee with the Casco Baykeeper recording
Learn more about Friends of Casco Bay’s ongoing data collection of PFAS in Casco Bay by watching the recording of our Coffee with the Casco Baykeeper webinar. Casco Baykeeper Ivy Frignoca and Community Organizer Sara Freshley discuss the results of this collaboration with Bigelow Laboratory.
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