K.I. SAWYER — The Air Force Civil Engineering Center is in the process of conducting its fourth five-year review at the former K.I. Sawyer Air Force Base. The contaminants which were previously found at some sites have continued to demonstrate degradation.

The routine review ensures that remedial actions continue to operate properly and as planned to protect human health and the environment.

Years ago, the AFCEC elected to conduct investigations under state statute to address the contaminant concerns. Many sites on the base were cleaned and a Baseline Remedial Action Plan was created to detail cleanup for remaining contamination sites, which occurred from Air Force operations during the base’s active period, said Mark Petrie, a regulator with the Michigan Department of Environment, Great Lakes and Energy who oversees Air Force investigations and cleanup activity at K.I. Sawyer.

“The air base is basically the same as a city, so it has the same kinds of problems that a city does,” Petrie said. “It’s a little different because it’s an Air Force base but there were landfills for solid waste disposal, there were gas stations, there were industrial operations, and what differs this from a city is the large volume of jet fuel that was used and the large amount of aircraft maintenance that went on. That generated the same kinds of problems you would see in a large city, but to some extent on a larger scale just because they ran so much fuel through there.”

One site at the former base that must be reviewed every five years is the landfill. Because the landfill reached capacity, it was covered to prevent precipitation from leaching into groundwater. Review of this site includes monitoring groundwater to ensure the protective liner is working properly and the periodic cutting of trees to prevent possible tearing of the liner, Petrie said.

The use of a solvent for cleaning parts at a former industrial shop on base also led to a large plume that needed remedial action. The AFCEC installed a pump-and-treat system to divert the direction of the plume to prevent the water supply from contamination. While not the intention, the system cleaned the plume, Petrie said.

“It’s one of the few instances I’m aware of where pump-and-treat actually cleaned up the problem to the point where there is no more plume remaining and all the wells have been abandoned,” he said. “It’s quite an unusual success story.”

Another site reviewed was a large fuel plume that resulted from bulk storage tanks, which caused jet fuel to sit on top of the water table migrating toward Silver Lake Creek. Various remedies were tried, but none was effective. Eventually, a collection trench was created in the floodplain to stop the product from reaching the creek and has been operating efficiently for decades, he said.

“They’re nearly at the point now to probably being able to demonstrate that it is no longer necessary to operate that. The fuel has been out there long enough that it’s degraded and it’s gotten more viscous to the point where it’s hardly mobile at all anymore,” Petrie said. “It’s been a long haul on that one but I think they’re approaching the point where they can stop operating, which is another success story, which I really didn’t anticipate in my career.”

While these sites at one point were or may have been a cause of concern, levels of contamination in every area were noted as lower during the review, Petrie said.

Another ongoing investigation by the AFCEC is the identification of PFAS, perfluoroalkyl and polyfluoroalkyl substances, an active ingredient in firefighting foam used at many airports. Releases of PFAS were noted at the base and is a major concern to AFCEC, Petrie said.

“That’s where they’re putting all their money. They are looking for any place where there’s potential for someone to drink it and if that’s the case they’re going to respond to it,” he said.

Fire Training Area 2 is the only PFAS area with the potential to affect residents, he added.

A total of 28 private water supply wells off base that could potentially have been affected by that plume were sampled and of those, 27 had no detectable levels of PFAS. One of the wells has been sampled and found to be clean on three separate occasions. The well was sampled multiple times due to its proximity to the 28th home, which had PFAS levels “well above” the drinking water standard, Petrie said.

AFCEC installed a water treatment system at the residence, which removes all traces of the substance from drinking water. The filter is replaced and water sampled from the treatment system every three months. Concentrations within that well remain constant, Petrie said.

“This stuff is difficult to deal with. There is very few treatment technologies available,” he added. “The costs to try to clean up the aquifer are exorbitant given the distance from the fire training area, so they’re trying to make sure no one else is affected by it and the one that’s affected by it continues to be safe with the treatment system.”

AFCEC’s work on this particular area will continue next year, he said. Eventually no further work will be necessary as all sites will be clean.

Petrie said when the Baseline Remedial Action Plan was approved in the mid-2000s, there were 20-something sites where there were water use restrictions because contaminants were present above unrestricted residential concentrations, either soil or groundwater or both.

“Since that time they have collected additional data at many of the sites and demonstrated that degradation has reduced the contaminants to the point where there’s no longer a threat posed by them … Things continue to get better,” Petrie said.

Petrie encouraged anyone interested in the review process to attend the annual meeting of the Restoration Advisory Board or contact him with questions at his office by calling 906-228-4853.

Trinity Carey can be reached at 906-228-2500, ext. 206.