A small laminated sign at a large children’s fishing pond in Fairfield warns fishermen not to eat their catch, but the sign is unreadable because of winter wear. The fishing holes next to Fairfield’s youth athletic complex on Industrial Drive are believed to be some of the most polluted waters in Maine. Penelope Overton/Staff Writer

The Maine Center for Disease Control and Prevention updated its fish consumption advisory list Tuesday, adding four freshwater sites containing so-called forever chemicals and expanding guidelines for other locations.

“These updates and expansions of Maine’s fish consumption advisories are part of our broader work to limit Maine people’s exposure to PFAS,” Dr. Puthiery Va, director of the Maine CDC, said in a written statement announcing the changes.

Per- and polyfluoroalkyl substances, or PFAS, are household and industrial pollutants that can be found in industrial products, such as firefighting foam, and many common household items, like stain-resistant carpets and waterproof clothing. They can linger indefinitely in ecosystems and can have dangerous effects on human health. Even trace amounts of these manmade compounds have been linked to compromised immune systems, low birth weights and several types of cancer.

Maine is one of the 17 states that are testing and have established some advisory thresholds.

The overwhelming majority of freshwater fishing locations remain untested because it is difficult to find a lab that can test the fish tissue, the turnaround time is long and the fees are high – $500 for every five-fish sample.

State officials had previously posted consumption advisories for water bodies ranging from the Mousam River in Sanford and the Presumpscot River in Westbrook to Durepo Pond in Limestone. The limits vary according to contamination levels.

Officials recently found evidence of PFAS at the following ponds, lakes, streams and rivers as a part of a yearslong testing effort that has identified more than a dozen contaminated sites:

• Belgrade and Oakland – McGrath Pond and Salmon Lake (consume no more than one meal per month of any fish species)

• Caribou – Aroostook River from the Aroostook River Reservoir to Haley Island in Fort Fairfield (consume no more than two meals per month of brook trout)

• Corinth to Bangor – Kenduskeag Stream from the Robyville covered bridge to the Penobscot River (consume no more than one meal per month of smallmouth bass)

• Monmouth and Winthrop – All of Annabessacook Lake (consume no more than 10 meals per year of black crappie)

The agency also expanded guidelines for three bodies of water with existing advisories:

• Fairfield to Sidney – Kennebec River from the Carrabassett Stream inlet just north of Route 23 to the Town Farm Brook inlet in Sidney (consume no more than nine meals per year of smallmouth bass and no more than five meals per year of black crappie)

• Limestone to Fort Fairfield – All of Durepo Pond and Limestone Stream (consume no more than four meals per year of brook trout and do not eat smallmouth bass)

• Unity and Thorndike – Halfmoon Stream from the Shikles Road in Thorndike to Sandy Stream, and Sandy Stream from the Stevens Road in Unity to Unity Pond (Consume no more than five meals per year of smallmouth bass. For Halfmoon Stream, consume no more than two meals per month of brook trout.)

With the new additions, a total of 16 bodies of water across the state are now under active freshwater fish consumption advisories because of PFAS. The warnings advise anglers to limit the fish they eat from certain locations and in some cases, suggest avoiding any consumption at all.

The state still stocks some of the contaminated waters with trout to encourage fishing even while warning anglers not to eat their catch, a practice criticized by some public health advocates.

A full list of advisories for Maine waters is available on the Maine CDC website.