28 March 2025
Water runoff from contaminated farmlands in central Maine is spreading forever chemicals into rivers and streams whose waters flow into the Kennebec River, new research by Colby College published on Monday found.
Because surface waters interconnect and mix, forever chemical pollution may spread far from sites of sludge spreading, according to the paper, published in the March 24 edition of the journal Environmental Research. Residents who don’t live on or near contaminated farms may still be harmed by ingesting tainted drinking water or freshwater fish, the paper said.
Even though Maine banned sludge spreading on land in 2022, the researchers detected per- and polyfluoroalkyl substances, known as PFAS, in waterways far away from farmlands in Fairfield, a hotspot for the pollution. The paper noted that PFAS contamination will continue to persist in the environment because of the very long time the chemicals take to break down.
The researchers discovered the spread after testing a shallow well of water they initially thought might be contaminated by PFAS in ski wax from a nearby cross country ski trail in Waterville, said Gail Carlson, assistant professor in Colby’s environmental studies department and co-author of the recent study. But state environment officials told her that no flooding had occurred that could have spread the PFAS from the trail into the well. She began to look for other sources for the PFAS.
The well is located at the northern edge of Waterville, next to Fairfield. The Messalonskee Stream, which is contaminated by PFAS, flows near the well, and its waters may get into the well to pollute it, she said. The PFAS in the stream likely flowed into it from another stream, the most contaminated waterbody in her study: Fish Brook.
Fish Brook runs through Fairfield, where runoff from contaminated farmlands is the likely source of pollution, Carlson said. The waterways lead to Maine’s third-longest river, the Kennebec, in Waterville.
“Not only are PFAS forever chemicals, but they’re mobile chemicals,” Carlson said. “So make sure you know what the surface waters are that you are taking your fish from. Be careful of the fish advisories. Pay attention to the state’s drinking water standards.”
Fish Brook had a very high level of perfluorooctane sulfonate, or PFOS, at 634 parts per trillion when the researchers measured it in March 2022. Maine’s health limit for a combination of six types of PFAS, including PFOS, is 20 parts per trillion, the equivalent to a drop of water in about 20 Olympic swimming pools.
The measurements the Colby researchers made to show how PFAS are moving are important contributions to the overall knowledge of forever chemicals, said Dianne Kopec, a faculty fellow at the University of Maine who specializes in toxic contaminants.
“I think it further confirms that PFAS knows no boundaries,” Kopec said. “It will not stay in one place. Water always runs downstream, so any contaminant that is put on land eventually makes its way into our rivers, into our groundwater and then downstream into our oceans.”
PFAS are manmade chemicals that have been linked to certain cancers by the U.S. Centers for Disease Control and Prevention and other health experts. In Maine, PFAS were in the sewage sludge spread heavily in the 1970s and 1980s as farm fertilizer. It was later found to have contaminated private wells on adjacent residences.
“The focus is on farmers and adjacent homeowners whose wells are contaminated,” Carlson said. “But we need to recognize that these chemicals don’t stay put in the soils they were applied to. There’s quite significant runoff happening straight into Waterville.”
Carlson said it is difficult to tell how much Messalonskee Stream contributes to PFAS in the Kennebec because there also are industrial sources, including wastewater treatment plants, that discharge waste into the Kennebec.
Overall, the Kennebec was less contaminated than the streams flowing into it, Carlson’s research found, as it is larger.
Carlson said Mainers should learn the PFAS counts in waterways near them. They should be careful not to gulp water or get it into their eyes when swimming or kayaking in a stream with high PFAS counts. And they should watch for any state advisories to not eat fish or animals in polluted areas.
Restrictions on products containing PFAS, such as those set to go into effect in Maine next year, should help reduce Mainers’ exposure to PFAS, Carlson said. Using water filters also will help, she said, as even a kitchen countertop filter will catch some PFAS. More information on PFAS in water is available on the Maine Center for Disease Control and Prevention and Defend Our Health websites.
Lori Valigra reports on the environment for the BDN’s Maine Focus investigative team. Reach her at [email protected]. Support for this reporting is provided by the Unity Foundation, a fund at the Maine Community Foundation and donations by BDN readers.