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Coffee with the Casco Baykeeper webinar on PFAS

Coffee with the Casco Baykeeper: PFAS video

Coffee with the Casco Baykeeper: PFAS video

In this video from our Coffee with the Casco Baykeeper series, Ivy Frignoca and Community Organizer Sara Freshley have a casual early morning conversation about our partnership with Bigelow Laboratory for Ocean Sciences to sample for PFAS in Casco Bay. Ivy shares insights from what we learned during our first year of PFAS monitoring in Casco Bay. Sara and Ivy also talk about what’s next in 2024.

PFAS are chemicals that are used in a wide variety of products from clothing to firefighting foam. They break down slowly so they build up in our environment and are detrimental to human health. Last year, Bigelow Laboratory for Ocean Sciences and Friends of Casco Bay partnered as we conducted the first study of PFAS in the waters of Casco Bay. Ivy will share an overview of PFAS monitoring at Friends of Casco Bay’s seasonal sites in 2023. Sara and Ivy will then talk about our more extensive plans to monitor the Bay and lower watershed for PFAS in 2024. All of this work is in collaboration with Bigelow Laboratory scientists, who developed the protocols and are analyzing the samples. We are excited to share our plans with you and how the data will help further our understanding of the health of our waters.

PFAS Sampling Results in Casco Bay

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 100 PFAS samples at 18 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.

Six months of sampling data from sites around Casco Bay were collected in 2023 by Bigelow Laboratory and Friends of Casco Bay scientists.
Six months of sampling data from sites around Casco Bay were collected in 2023 by Bigelow Laboratory and Friends of Casco Bay scientists.

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 at our Coffee with the Casco Baykeeper webinar

Invitation to Coffee with the Casco BayKeeper PFAS discussion

Learn more about Friends of Casco Bay’s ongoing data collection of PFAS in Casco Bay this Thursday, March 21 from 8:00 a.m. to 8:45 a.m. at our Coffee with the Casco Baykeeper webinar. Grab a cup of coffee and hop online to hear Casco Baykeeper Ivy Frignoca and Community Organizer Sara Freshley discuss the results of this collaboration with Bigelow Laboratory.

What: Coffee with the Casco Baykeeper: PFAS
When: Wednesday, March 21, 8:00 to 8:45 a.m.
Where: Zoom, Register here to receive a link to attend

Our Top 10 Moments of 2023

As this year comes to an end, let’s reflect and celebrate the many ways that we worked together to protect the health of Casco Bay in 2023. Here are our top ten stories of the year:

1) We won a four-year moratorium on new sources of pollution into the lower Presumpscot River. The moratorium prevents the permitting of new industrial or wastewater discharges into the river near where it empties into Casco Bay. As the Presumpscot drains two-thirds of the Casco Bay watershed, this was a big win for our waters. Portland Press Herald wrote an in-depth story on this effort. Our lead advocate, Casco Baykeeper Ivy Frignoca won the Chief Poulin Award for her work on the moratorium. Ivy is shown here receiving the award from Friends of the Presumpscot River board member, Will Plumley.

2) More than 100 of our volunteer Water Reporters deepened their knowledge about Casco Bay. Volunteer Water Reporters attended a wide array of meet-ups and trainings all around the Bay this year. Water Reporters spent time with experts and heard the most up-to-date information about living shorelines, marsh restoration, invasive species, and stormwater pollution.

3) The “Sensor Squad” is moving science forward for Casco Bay and all of Maine’s coastal waters. Good decisions are made using good data. Led, in part, by our Staff Scientist Mike Doan, the Sensor Squad is working to ensure we are using the most accurate climate change and acidification techniques and protocols we can. This work is a part of Maine Ocean Climate Collaborative, a coalition of scientists and marine organizations from the University of New Hampshire to the border of Maine and Canada working to improve climate change data collection. Friends of Casco Bay helps to lead the Collaborative.

4) Passamaquoddy Language Keeper Dwayne Tomah was the featured speaker at our Members Annual Meeting in August. He shared the Passamaquoddy word for ceremony, “olotahkewakon,” noting that our gathering was a ceremony for our mother earth. Dwayne’s refrain throughout the evening was “We are all in this together.” Watch the inspiring talk here.

5) We maintained the strength of the permit that regulates stormwater pollution from large urban communities. You may remember that we celebrated this stricter permit as our top story of 2022. Stormwater is one of the largest sources of pollution into Casco Bay. Since the permit that regulates urban stormwater went into effect in July 2022, we have been working to ensure that it is properly implemented. In November, the Maine Board of Environmental Protection agreed with us that the Maine Department of Environmental Protection must ensure that towns covered by the permit implement low-impact development ordinances that include nine strategies designed to reduce stormwater pollution from new construction and redevelopment.

6) The City of South Portland launched 100 Resilient Yards, providing a grassroots way to bring best practices in yard care directly to neighborhoods around the city. Residents and businesses who took part in the program were given technical and physical assistance to build healthy soils that protect Casco Bay. Experts and volunteers helped residents build rain gardens, grow pollinator gardens, and more. We hope other towns around the Bay look at this program as a model!

7) We organized 15 fun coastal cleanups, including one with the surf rock band Easy Honey and one with the Harpswell Heritage Land Trust. These cleanups gave community members a hands-on way to make a direct difference in the health of our waters by preventing waste and litter from being washed into the Bay.

8) We hired Community Organizer and Volunteer Coordinator Sara Freshley! Over the past 10 months, Sara has become an integral part of our team. She’s helped deepen the knowledge of our Water Reporters, organized storm drain stenciling and coastal cleanups, and worked to expand our outreach efforts.

Pile of expired flares9) We helped organize an expired flare collection event in partnership with the U.S. Coast Guard Auxiliary Casco Bay and the Maine State Fire Marshall. The event was a great success, collecting 1,945 expired marine flares. Marine flares are pyrotechnic devices that boaters can use as a distress signal in emergencies. They burn at high temperatures, posing a serious fire hazard for long-term storage. Flares also contain toxic chemicals that can contaminate water and soil. Due to these hazardous qualities, it is illegal to throw flares in the trash, and ill-advised to store them at home.

Scenic Category Winner 1st Place, Student Category Winner, Best of Show, by Ava McKinley

10) We got in touch with our artistic side! Our online event, Water as Inspiration, brought together three regional artists to draw the connections between creativity, the environment, and climate change. We had dozens of submissions to “Frame the Bay,” our first-ever photo contest at our Members Annual Meeting. And we shared the stage with filmmaker Maximillian Armstrong at our Film Fest for Casco Bay.

As YOU know, Casco Bay is an inspiration! Thank you for helping us protect this amazing place and for being a Friend of Casco Bay.

Ever-Changing Casco Bay

Casco Bay is everchanging. The Bay changes with each tide, each day, and each season. And now, because of climate change, our coastal waters are transforming in different ways and faster than we thought possible.

At our EverChanging Casco Bay event on November 28, Staff Scientist Mike Doan dove into the data we use to track the health of the Bay. Community Organizer and Volunteer Coordinator Sara Freshley shared observational data our volunteer Water Reporters posted over the course of the summer. Casco Baykeeper Ivy Frignoca discussed how these scientific and observational data are helping to move the needle for a cleaner, more protected Casco Bay.

 

If you missed the event or want to rewatch it, click here. If you don’t have time to watch the whole event, you can click here to hear Mike delve into the datahere for Sara talking about Water Reporters, and here to listen to Ivy describe the big picture.

More than 60 Friends attended the event along with members of the media. The Portland Press Herald/Maine Sunday TelegramMaine PublicBangor Daily News, and WGME covered the event and the issues we discussed.

How we are moving science forward

Sensor Squad Moves Science Forward

We rely on scientific data on the health of Casco Bay to inform our advocacy and stewardship efforts.

Good decisions are made using good data. That’s the idea behind the Maine Ocean Climate Collaborative.

“The Collaborative is made up of some of the best saltwater scientists in Maine,” says Casco Baykeeper Ivy Frignoca. “By sharing research and knowledge of climate change science, water quality monitoring issues, and ocean climate policies, we can better protect all of our coastal waters.”

Ivy coordinates the Collaborative, which includes Bigelow Laboratory for Ocean Science, Bowdoin College, Casco Bay Estuary Partnership, Downeast Institute, Friends of Casco Bay, Governor’s Office of Policy, Innovation, and the Future, Island Institute, Maine Center for Coastal Fisheries, Maine Department of Environmental Protection, Maine Department of Marine Resources, University of New Hampshire’s Ocean Processes Analysis Laboratory (OPAL), and Wells  National Estuarine Research Reserve (Wells Reserve).

Staff Scientist Mike Doan (left photo) and Science and Advocacy Associate Heather Kenyon (right photo) are working with colleagues up and down Maine’s coast to improve our collective knowledge of how acidification and climate change may be affecting our waters.

A key part of the Collaborative’s current work is to develop a report of recommended equipment, sampling techniques, and quality assurance protocols to serve as a guide for researchers, agencies, and institutions up and down Maine’s coast to better monitor climate change and acidification. For this effort, Friends of Casco Bay Staff Scientist Mike Doan is working closely with colleagues from OPAL and Wells Reserve.

“We call ourselves the ‘Sensor Squad,’” says Mike. “Staff from Wells Reserve and Friends of Casco Bay are testing equipment and protocols in real-world conditions and comparing our data to OPAL’s gold standard. The goal is to ensure we are getting the most accurate climate change and acidification data we can. As the science evolves, we have to evolve, too.”

While the “Sensor Squad” may not look like superheroes, by working together, the scientists are helping improve Maine’s understanding of climate change.

“While our mission is all about Casco Bay, we recognize that climate change doesn’t stop at the watershed’s border,” says Executive Director Will Everitt. “The State of Maine can use our work as a model for what a statewide monitoring program can look like. When state agencies who are tasked with managing and protecting our marine ecosystems have better data, ultimately that helps Casco Bay and all of our coastal waters.”

 

The work of the “Sensor Squad” is supported by generous grants from Maine Outdoor Heritage Fund, donor-advised funds at the Maine Community Foundation, and by Friends of Casco Bay’s members. 

31 Years of Seasonal Sampling

Today, on World Ocean Day, we are celebrating our 31st year of collecting seasonal water quality data on the health of Casco Bay!

It also happens to be Casco Baykeeper Ivy Frignoca’s birthday – Happy Birthday, Ivy!

Every year, from May to October, Ivy and Staff Scientist Mike Doan take to our Baykeeper boat and truck to assess water quality at more than 20 locations in Casco Bay. This seasonal sampling includes measuring temperature, dissolved oxygen, pH, total nitrogen, water clarity, salinity, and chlorophyll fluorescence (an estimate of phytoplankton abundance). 

This year, for the first time, seasonal sampling will include testing for PFAS contamination in Casco Bay in collaboration with marine chemist Christoph Aeppli of Bigelow Laboratories for Ocean Sciences. PFAS are a class of widely-used, long-lasting chemicals and are an emerging pollutant of concern in Maine and around the world.

Staff Scientist Mike Doan collects water quality data from our Casco Baykeeper boat, R/V Joseph E. Payne. Mike uses a data sonde – a scientific device that measures water quality characteristics – to measure temperature, salinity, dissolved oxygen, and other parameters.

“There is an important gap in PFAS testing in Maine,” says Ivy. “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.” 

Our 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. 

At Friends of Casco Bay, we use all of our seasonal sampling data to help assess the health of the Bay. Mike compares this seasonal work to a regular health check-up. “Like a doctor checking your blood pressure, if we find an anomaly or problem, we can do more thorough investigations,” says Mike. 

Seasonal sampling also enables us to assess water quality over a large area by visiting more than 20 different sites in the Bay. That’s a key difference from our Continuous Monitoring Stations, which collect data at a much higher frequency from three locations in Casco Bay.

Friends of Casco Bay conducts seasonal water quality monitoring at more than 20 locations in Casco Bay, marked by the blue dots. We also gather year-round data at their three Continuous Monitoring Stations, marked by the yellow stars.

The seasonal data we collect this year will add to our historic 30-year dataset, which has become one of the most long-term marine water quality datasets in the United States. Our data show that Casco Bay is warming at the same alarming rate observed in the greater Gulf of Maine. They have helped to designate Casco Bay as a federal No Discharge Area and strengthen legal protections for large areas of the Bay.

We share our data with other scientists as well as with state and federal agencies that use them to meet regulatory mandates. 

“For over three decades, Friends of Casco Bay’s monitoring efforts have provided scientists and regulators a crucial part of the data used to understand the condition of Casco Bay,” says Curtis Bohlen, Director of the Casco Bay Estuary Partnership, one of 28 federal National Estuary Programs. “The next thirty years will see unprecedented change in the Bay. Friends’ monitoring will undoubtedly be at the center of our efforts to witness and understand those changes.”

The Maine Ocean Climate Collaborative Provides a Model to Move Maine Forward

Studying changing coastal ecosystems comes with unique challenges – Friends of Casco Bay and our partners are taking them on.

Staff Scientist Mike Doan designed Friends of Casco Bay’s Continuous Monitoring Stations, which serve as a model for measuring the influence of climate change on Maine’s coastal waters. Mike is working with other scientists to develop shared methods to collect and analyze marine climate change data, a key goal of Maine’s Climate Action Plan.

Friends of Casco Bay is facilitating the newly formed Maine Ocean Climate Collaborative, a coalition of scientists and marine organizations from the University of New Hampshire to the border of Maine and Canada working to improve climate change data collection. The Collaborative’s work acts as a model for establishing a coastwide climate change monitoring network, a key goal of Maine Won’t Wait, Maine’s Climate Action Plan.

“[The state of Maine is] participating in an ocean climate collaborative with academic and non-profit partners to coordinate and improve Maine-focused coastal and ocean acidification monitoring relevant to meeting the goals of Maine Won’t Wait,” reads the state’s two-year progress report on the Climate Action Plan. This is the Maine Ocean Climate Collaborative, which Friends of Casco Bay helps to lead!

In order to respond to the impacts of climate change, policymakers, resource harvesters, and other marine-dependent persons and industries must have reliable data. With these data in hand, they can make informed decisions to protect coastal resources, foster resilient habitat, and adapt fisheries management. 

This is easier said than done. Collecting data in coastal ecosystems comes with highly technical and unique challenges. In nearshore environments such as Casco Bay, the confluence of freshwater and saltwater, and the influences of human populations make studying water chemistry complex and difficult. 

“Climate change is challenging to measure, especially along the coast,” says Casco Baykeeper Ivy Frignoca. “The Collaborative brings together some of the best scientific minds in Maine who are working to better understand how nearshore conditions are changing in response to excess carbon in the water. Together we can best compare equipment, evaluate data, and understand the changes we are seeing.” 

One of the Collaborative’s current tasks is to compare and refine technology, quality assurance standards, and monitoring methods to better measure acidification in coastal waters. Staff Scientist Mike Doan is working closely on this effort with two other members of the Collaborative: Wells National Estuarine Reserve, and University of New Hampshire’s Ocean Process Analysis Laboratory. 

Friends of Casco Bay collects pH data (a measure of acidity) at our three Continuous Monitoring Stations. Click on the graph to view these and our other continuous monitoring data yourself!

The ability to effectively measure acidification is vital because oceans around the world are becoming more acidic as they absorb carbon dioxide from the atmosphere. Ocean acidification lowers the amount of minerals available for shell-building organisms like clams and oysters. It can also cause some harmful species of algae to bloom faster and produce more toxins. Our understanding of these impacts and others are constantly evolving because ocean acidification is a relatively new area of scientific research. 

Measuring acidification along the coast is uniquely challenging because most scientific monitoring equipment is designed specifically for freshwater or offshore ocean environments.

“Effective water science in the nearshore calls for creative solutions,” says Mike. “Fortunately, everyone in this group has experience doing just that, innovating to move coastal and climate science forward.”

This technology and monitoring methods work is supported by a $200,000 grant from the Maine Community Foundation. What Mike and the team learn will be shared with the rest of the Collaborative, enabling comparable marine climate data to be gathered throughout the Gulf of Maine.

Maine and ocean acidification: how did we get here?

Maine was the second state in the nation to recognize that ocean acidification poses a serious and little-understood threat to shellfisheries and coastal ecosystems. Since 2014, the state and marine organizations have convened multiple initiatives to better understand and address ocean acidification. This work ultimately resulted in a goal outlined in Maine’s Climate Action Plan to create a coastwide network of scientists to collect climate and ocean acidification data in the Gulf of Maine. These data would be accessible to inform environmental policy and fisheries management. 

The Maine Ocean Climate Collaborative provides a model for how this network can work. The Collaborative includes Bigelow Laboratory for Ocean Sciences, Bowdoin College, Casco Bay Estuary Partnership, Downeast Institute, Friends of Casco Bay, Governor’s Office of Policy Innovation and the Future, Island Institute, Maine Center for Coastal Fisheries, Maine Department of Environmental Protection, Maine Department of Marine Resources, the University of New Hampshire, and Wells Reserve. The Maine Climate Council Coordinator also participates.

2023 Water Reporter Kickoff

With 578 miles of shoreline, Casco Bay is large. It takes many of us working together to keep an eye on this special place we all love. By volunteering as a Water Reporter and taking photos of algal blooms, eelgrass, rising sea levels, pollution, and more, you can help us to improve and protect the health of Casco Bay.

Come and learn about this exciting volunteer program at our 2023 Water Reporter Kickoff! Join us at Winslow Park in Freeport to learn specific ways you can help protect the Bay this summer. Together we will learn marine science basics and connect with fellow Water Reporters keeping an eye on Casco Bay.

After our time at Winslow, we will head to Goodfire Brewing (only 5 minutes away) for snacks and beer. There we will discuss using the Water Reporter app and any other questions you may have. It will also be a time to gather and talk about all things Casco Bay.

What: 2023 Water Reporter Kickoff
When: Saturday, May 27, 2023 from 11:30 a.m. – 1:30 p.m.
Where: Winslow Park, Staples Point Rd, Freeport, Maine
(Around 12:30 p.m., we’ll head to Goodfire Brewing Company, 180 South Freeport Rd, Freeport, Maine. Friends of Casco Bay will purchase some appetizers to share and you can treat yourself to a good local beer from the brewery!). 

Please email volunteer [at] cascobay [dot] org to RSVP. If you cannot make it to this event, don’t worry. We will be hosting more Water Reporter meetups throughout the year. 

Thank you to L.L.Bean, Ferris Olson Family Foundation for Ocean Stewardship, Allagash Brewing Company, and our members for their support of our Water Reporter program.

Nab Data Suggest Land-Based Sources Contribute to Nitrogen Pollution

166 volunteers collected water samples from Portland Harbor to help measure and address nitrogen pollution. Here is what we found.

It was a sweltering summer morning on August 7, 2022 when 166 volunteers descended on Portland Harbor to collect water samples for nitrogen analysis.

After sending the 178 samples collected that day to the University of Maine Darling Marine Center Laboratory for analysis, the results are in.

Data from the Nab show nitrogen levels are generally highest near the shores of Portland Harbor, suggesting land-based sources contribute to nitrogen pollution. Each dot on the map represents one water sample. The dots are color coded based on the Maine Department of Environmental Protection’s nitrogen advisory thresholds. Green dots show healthy levels of nitrogen. Yellow dots show nitrogen levels that can harm eelgrass habitat. Red dots show nitrogen levels that can lead to low amounts of oxygen in Casco Bay, which can lower water quality and harm marine life.

The Nab data show nitrogen concentrations in Portland Harbor are generally highest near the shore. Lower concentrations of nitrogen are often observed in samples collected by boat from the mouth of the harbor and the middle of the harbor channel. These data suggest that land-based sources of excess nitrogen – a stormwater outfall, for example – enter the harbor at the shoreline and diffuse as water circulates with the tides.

“Seeing the data all together is remarkable,” says Staff Scientist Mike Doan. “Having so many samples collected at once gives us a robust image of nitrogen conditions in the harbor. Our incredible volunteers made this happen.” Mike adds that it is important to keep in mind that these data represent a snapshot of nitrogen conditions in the Bay’s dynamic ecosystem.

Mike compared data collected this summer to the data collected at our first Nab in 2016. The 2016 data also show nitrogen concentrations are highest near the shore. However, a key difference between the two Nabs was the weather.

The 2016 Nab coincided with a large storm. In fact, it was still raining when water samples were collected. Conversely, the 2022 Nab happened on a hot day during a summer drought.

Alicia Richards, Friends of Casco Bay’s 2022 Summer Intern, scoops water into a sample jar at Nabbing Nitrogen in August. 166 volunteers collected water samples that day from the shores of Portland, South Portland, surrounding islands, and by boat in Portland Harbor. The Nab focused on the harbor because it is showing signs of stress from nitrogen pollution.

“If land-based sources of nitrogen are affecting the harbor, we would expect nitrogen levels near the shore to be higher after a rainstorm than during a drought, and that is generally what we saw,” says Casco Baykeeper Ivy Frignoca. “The next step is to use these data to see if there are specific sources of nitrogen around the harbor that can be addressed and to help set limits in Clean Water Act permits that decrease nitrogen discharges to healthy amounts.”

Excess nitrogen can come from many sources. Sometimes the source is easy to identify because it comes from a specific spot, like a wastewater treatment plant, stormwater outfall, or combined sewer overflow discharge. Other sources can be more difficult to identify because they are picked up by stormwater that sheets off the land when it rains. These sources can include fertilizers, car exhaust, pet waste, and more.

Data from the Nab are being used to help the Maine Department of Environmental Protection (DEP) develop nitrogen criteria for Casco Bay. These criteria will describe the levels of nitrogen that water bodies can safely absorb. They will also influence nitrogen discharge limits in Clean Water Act permits. Angela Brewer, who leads the marine unit of the Bureau of Water Quality at DEP, is excited to have these data.

“The Nab data provide a unique perspective that is essential to understanding the nitrogen dynamics in Portland area surface waters,” says Angela. “This perspective is only possible with Friends of Casco Bay’s extensive and dedicated volunteer network.”

Thank you to the volunteers who collected water samples with us at Nabbing Nitrogen, and to Allagash Brewing Company and our members for funding for this community science event. You made this work possible.

Why Does Nitrogen Matter?

Eelgrass meadows in Casco Bay declined in size by 54 percent between 2018-2022, a loss described as “staggering” by the Maine Department of Environmental Protection in a January 2023 report. Many factors can contribute to loss of eelgrass. Nitrogen pollution is one of them, and unlike other contributing factors such as warming water temperatures, the amount of nitrogen in the Bay can be controlled at a local level. Photo credit: Steve Karpiak

Nitrogen is naturally found in marine waters. A healthy amount of nitrogen fertilizes algal blooms that form the base of the food chain in Casco Bay. But excess nitrogen from human sources such as wastewater, fertilizers, stormwater, and air pollution can cause excessive algal growth that harms the health of the marine environment. Some of the impacts of nitrogen pollution include degrading eelgrass beds (which are critical fish nursery habitat), exacerbating coastal acidification, lowering oxygen levels, and shutting down shellfisheries.

Mike’s Field Notes: Warm Winter Waters in Casco Bay

In this 4 minute video, Staff Scientist Mike Doan breaks down the data from our Continuous Monitoring Station in Yarmouth that show this past winter was unusually warm for Casco Bay. In addition to watching Mike’s video, you can read about these data and the many impacts of warming waters (such as more green crabs and less eelgrass), here.

P.S. You can try listening to the Bay yourself by checking out data from our Continuous Monitoring Stations.