A sign at Portland’s capped landfill off Ocean Avenue is seen in 2017. Some of Maine’s defunct landfills are leaking potentially harmful forever chemicals into the drinking water supplies of nearby homes. Shawn Patrick Ouellette/Staff Photographer, file

Some of Maine’s defunct landfills are leaking potentially harmful forever chemicals into the drinking water supplies of nearby homes at levels that are up to 100 times higher than what Maine deems safe to drink.

Data released to the Press Herald show 23 closed landfills from Kittery to Corinna are responsible for contaminating 51 drinking wells. However, that total may grow because Maine has only tested 95 of its more than 400 shuttered landfills.

Some contaminated wells tested just over Maine’s standard of 20 parts per trillion for the six per- and poly-fluoroalkyl substances, or PFAS, that it tracks. One well near the Wayne landfill tested at 20.3 parts per trillion.

Compare that to a Standish well, which topped the state list at 2,510 parts per trillion.

“While upsetting, the results really are not that surprising,” said Dana Colihan, a director at Slingshot, an environmental health and justice group active across the Northeast. “For most landfills, especially unlined landfills, it is incredibly likely for them to be leaking leachate and causing PFAS contamination.”

To understand these numbers, imagine an above-ground swimming pool measuring 20 feet across, 4 feet deep and holding 10,000 gallons of water. So far, the most contaminated well found in the state’s defunct landfill investigation has a PFAS concentration akin to four drops of ink in that pool.


Maine’s interim limit is the equivalent of 20 drops spread out over 1,000 such pools.

Federal regulators say that even trace amounts of two of the six PFAS chemicals Maine tracks are too dangerous to ingest and have been linked to premature deaths, cancer, liver and heart impacts in adults, and immune and developmental impacts to infants and children.

That is why federal regulators set new national drinking water standards for PFAS just last week. Those standards are significantly stricter than Maine’s limits. Maine plans to adjust its standards to match, but state officials say it will take time to change the law and know how it affects Maine’s PFAS response.

The number of contaminated wells would likely be higher if Maine began using the new federal limits.

The data show the average concentration among the 51 tainted wells is 174.3 parts per trillion, or ppt. The closed Corinna, Kittery and Lamoine landfills were responsible for the most well contaminations, but Standish, Belfast and Oakland had the highest average PFAS concentrations.

Among those in southern Maine, the three residential wells contaminated by the Portland Oceanside Avenue landfill had the highest average concentration of 119.5 ppt. Lewiston was second at 116.6 ppt, Kennebunkport at 87.1 ppt, Westbrook at 75 ppt, Gorham’s at 68.2 ppt, and Kittery at 42.5 ppt.



When tests come back high, the Maine Department of Environmental Protection and the Maine Center for Disease Control and Prevention work with the homeowner to provide an alternative source of clean drinking water while a filtration system is installed.

The homeowners don’t have to pay for remediation if the contamination is linked to a leaky landfill or a state-licensed agricultural sludge application. The state or the landfill operator will pay installation costs, which can run $3,400 to $15,600, and $5,300 in annual upkeep.


Forever chemicals got their name because they can linger in the environment for decades. Even trace amounts of some PFAS found in common household items are considered a public health risk. They are linked to compromised immune systems, low birth weights and several types of cancer.

“We talk about PFAS as forever chemicals. Well, landfills could be considered forever sites,” said Mike O’Connor, a senior environmental hydrologist with the Maine Department of Environmental Protection. “Landfills stick around a long time. People before me have been working on these landfills for decades, and I’ll be working on these landfills for decades to come.”


In 2021, the state adopted a law requiring the DEP to investigate forever chemical contamination of land and groundwater. O’Connor presented the results of the ongoing landfill component of that investigation at a sustainability conference last month in Augusta.

The law required licensed landfills to test collected drainage water, or leachate, for the presence of forever chemicals. As rainwater seeps through a landfill, it is contaminated by the waste. It usually winds up at a municipal or industrial sewage plant that empties into a nearby pond, lake, river or the ocean.

The leachate emerges from the landfill as a smelly black, yellow or orange discharge that often contains dissolved organic matter, hydrogen sulfide, heavy metals, PCBs, dioxins and, according to state tests, at least some forever chemicals.

In a January report to the Legislature, the DEP reported high levels of forever chemicals in wastewater from the 25 landfills that collect and manage leachate. The average concentration was 2,440 ppt of the six PFAS chemicals used to judge drinking water safety in Maine.

The Hartland municipal landfill and the Twin Rivers Mill landfill in Frenchville had significantly higher average concentrations at 18,540 ppt and 13,820 ppt. A closed municipal solid waste landfill that has a leachate collection system in Brunswick came in third with 4,060 ppt.

Using the swimming pool analogy, Brunswick’s concentration is akin to four drops; Hartland’s is 18 1/2.



There is no evidence the leachate that forms when rain trickles through an active landfill is escaping from the holding tanks, ponds or lagoons when it is stored in landfills with collection systems, but then again, no one is looking – the monitoring wells set up to detect leaks are not looking for PFAS.

Most of the 400 defunct landfills in Maine are unlined and have no collection systems, however. The water draining through those landfills seeps into the groundwater or empties into nearby rivers and lakes, depending on their location and area hydrology, O’Connor said.

Some closed landfills are so unremarkable that neighbors may have forgotten they even exist, O’Connor said. They may be relatively small compared to today’s modern landfills and located in a remote location in the woods. Some don’t show up on maps.

While the state is installing filtration systems, the landfill operators are not doing anything wrong. That is because there are no state or federal regulatory limits on PFAS in landfill leachate or how much can be found in the wastewater discharged into our rivers. At least, not yet.

The EPA hopes to set PFAS regulatory limits on both landfill leachate and the treated wastewater that communities and businesses are allowed by permit to discharge into our rivers and streams sometime this year.

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