PFAS testing underway at Dillingham wells

Feb 27, 2019

Wells near the Dillingham airport are being tested for PFAS contamination. According to the Alaska Department of Health and Social Services, water that exceeds its minimum action level is not safe to drink.

The area that will be tested for PFAS contamination. The bright red dots are PFAS discharge location, and the small red dot marks the Holy Rosary Catholic Church. The Alaska Department of Transportation says the source of the PFAS contamination was firefighting foam used in annual testing at the Dillingham Airport.
Credit Alaska DOT&PF


The environmental firm Shannon & Wilson, Inc. is sampling wells around the Dillingham Airport for PFAS (per- and polyfluoroalkyl substances). The testing continues through March 1.

On Tuesday evening, state representatives held an informational meeting in Dillingham to present their timeline for sampling.

"Right now we really are just focusing on that drinking water exposure," explained Bill O’Connell, an environmental program manager for the DEC. "I expect this is going to be kind of a long-term effort. Normally, the way that our site characterization unfolds is that we start with the place where the contaminant was released and you work your way outward. Because of the drinking water impacts we kind of did that backwards and we jumped out to the drinking water wells."

Once the samples are collected, it will take three to four weeks for the results to come in.

Last month, the popular well at Dillingham's Holy Rosary Catholic Church tested positive for PFAS contamination. The well water contained 186 parts per trillion – more than three times the Alaska Department of Environmental Conservation's health advisory level of 70 ppt. The state tested eight other Dillingham wells at that time that showed PFAS levels of no more than 22 parts per trillion.

At Tuesday's meeting, many questions from community members focused on how to mitigate the levels of PFAS if the results show contamination above the minimum action level. According to O'Connell, DEC would work to provide safe water to impacted residents.

"The interim solution there would be whole-house treatment systems – filtration systems," O'Connell said. "Granular activated carbon is the typical action treatment method. But it's considered a point-of-entry system, where the well water enters the house and goes through the filter. So all the water provided to the house it treated, versus a point-of-use filter, which is at a spigot underneath the sink."

Another factor that could impact the effectiveness of a filter over time is the water quality in general. 

"An activated carbon filter is going to absorb the PFAS chemicals," O'Connell said. "But if you've got a lot of other natural organics in your water, carbon's just not going to last as long. And so trying to determine how long does that carbon last – that's sort of the testing phase of those filters."

He added that if contamination is detected, designing, building and installing a new system for a residence would take a minimum of four months. 

In Dillingham, the city's water system is limited to the downtown area. After PFAS was detected at Holy Rosary's well, the state worked with the City of Dillingham to establish a temporary, alternative water source. Now, residents can fill their water containers at a spigot on the north side of the Dillingham Senior Center.

PFAS chemicals are used in firefighting foams, and the Alaska Department of Transportation & Public Facilities says the contamination is a result of annual testing of firefighting equipment at the Dillingham Airport. That testing has been conducted in Dillingham since 1973 to maintain the airport's certification. But in light of its impact on water quality, the Federal Aviation Administration has allowed the Dillingham airport to forego use of the foam testing and instead use dry chemical.

Drinking contaminated water is a primary source of PFAS exposure. But the health effects of long-term exposure are not yet established. Dr. Kristin Bridges, a DHSS representative who spoke on Tuesday, said that testing has shown that the chemicals could pose health risks to the gastrointestinal, cardiovascular, immune and reproductive systems, among others.  

"DHSS recommends that if your water is 70 parts per trillion or more you should not drink it," Bridges said. "You should not prepare baby formula with it, you shouldn't give it to your pets or any other animals. It is safe to brush your teeth if you're not swallowing any of it, but you may want to exercise caution, especially with young kids, and just not take the risk."

Bridges added that although DHSS says it is safe to shower, bath and wash clothes with water that contains high levels of PFAS, doing so could contaminate the surrounding groundwater. She also cautioned that the health risks could be greater for children who consume water or food contaminated with PFAS. 

According to O’Connell, the results from this round of well testing will tell them a lot about the next steps that need to be taken in Dillingham.

"Once this sampling is completed, we'll be able to map all of these sample locations and, ideally, draft a map that shows here is where it exceeds the DEC action level. And based on that we may or may not need to expand the sampling area," he said. "I'm assuming the reason why we're sampling so many different wells is because I think in Gustavus we had to go out there two or three different times before we actually got them all, and so it's much easier just to sample as many as we can while we're here."

DEC has been testing for PFAS near airports and Department of Defense sites around the state, with a focus on communities that use groundwater for drinking water. PFAS has been detected at multiple locations; in Bristol Bay, a well near the King Salmon Airport also tested positive for contamination in January.

If you have an active well at your home or business near the airport, you can call Shannon & Wilson, Inc. at 907-371-9022.

Contact the author at or 907-842-2200. 

Correction: Mr. O'Connell said that the typical treatment method for PFAS chemicals is granular activated carbon, not radioactivated carbon as originally written.