Mike Doan, staff scientist with Friends of Casco Bay, uses a data sonde to collect water quality data from the organization’s research vessel, the Joseph E. Payne. The organization’s long-running water monitoring program will add PFAS testing this year.

Friends of Casco Bay is beginning its 31st year of collecting seasonal water quality data. The monitoring program assesses water quality at more than 20 locations in the bay, including locations in Harpswell waters. The initiative will begin testing for PFAS contamination in Casco Bay this year, in collaboration with the Bigelow Laboratory for Ocean Sciences.

Friends of Casco Bay’s 30-year data set includes measurements of temperature, dissolved oxygen, pH, total nitrogen, water clarity, salinity, and chlorophyll fluorescence (an estimate of phytoplankton abundance). The organization uses the data to assess the environmental health of Casco Bay and shares the data with other scientists, as well as state and federal agencies that use the information to meet regulatory mandates.

This year, Friends of Casco Bay is measuring PFAS levels in the bay by working with marine chemist Christoph Aeppli, of the Bigelow Laboratory for Ocean Sciences. PFAS stands for perfluoroalkyl and polyfluoroalkyl substances, a group of long-lasting chemicals that has emerged as a pollutant of concern in Maine and around the world.

“There is an important gap in PFAS testing in Maine,” said Casco Baykeeper Ivy Frignoca. “Current monitoring for contamination in sources like drinking water, fish tissues, and wastewater appropriately focus on public health. However, we don’t know how PFAS pollution is affecting water quality and the environment more broadly, especially in tidal waters like Casco Bay.”

Friends of Casco Bay’s collaboration with Bigelow this summer will help develop a baseline understanding of PFAS levels in Casco Bay, and lay the groundwork for testing in the marine environment moving forward.

Friends of Casco Bay has grown one of the most long-term marine water quality data sets in the country. The data shows that Casco Bay is warming at the same alarming rate observed in the greater Gulf of Maine. It has helped to designate Casco Bay as a federal No Discharge Area and strengthen legal protections for large areas of the bay.

“The next 30 years will see unprecedented change in the bay,” said Curtis Bohlen, director of the Casco Bay Estuary Partnership. “Friends’ monitoring will undoubtedly be at the center of our efforts to witness and understand those changes.”