ONE OF SEVERAL

Site SS-57 on the former Wurtsmith Air Force Base (WAFB) in Oscoda, seen here, was once the location of the apron hydrant fuel system. It was during the latest Wurtsmith Restoration Advisory Board meeting when an update was given on the remedy implementation and performance monitoring at SS-57, to address the fuel constituents which exist at this site. Located in the central part of WAFB, SS-57 is among 20 other installation restoration program sites on the former base.

OSCODA – The following is the second of a two-part story on the latest Wurtsmith Restoration Advisory Board (RAB) meeting. The group convened in January, and a recent publication highlighted their talks on transparency associated with the contamination at the former Wurtsmith Air Fore Base (WAFB) in Oscoda; information on the per- and polyfluoroalkyl substances (PFAS) remedial investigation (RI) at WAFB; and the feasibility study at landfills 30 and 31 (LF-30/31).

Along with a discussion on the Van Etten Lake (VEL) PFAS plume, other topics covered during the virtual event included the WAFB performance-based remediation (PBR) overview. Shared by Dirk Pohlmann of Bay West LLC, he summarized both the contract which Bay West shares with the company Wood, as well as the most recent active remediation application at WAFB’s SS-57 site.

Bay West and Wood are currently operating on a five-year PBR contract, which will end in June. The work under this general services administration task order includes a full range of environmental remediation activities necessary for remedial action operation (RA-O), long-term management (LTM), remedial actions (RAs), optimization and other activities supporting progress to site closeout.

Pohlmann said there are 21 installation restoration program (IRP) sites at WAFB which are being addressed under the Comprehensive Environmental Response, Compensation and Liability Act. These sites have been broken up, with Bay West handling 19 of them. Wood has two sites, plus the base-wide vapor intrusion study.

According to Pohlmann, the largest component is the RA-O of the active groundwater (GW) remediation systems, which consist of a number of sites. “The first two are Arrow Street and benzene plant, that covers SS006, SS017, SS021, SS047 and SS-57,” he said, noting that these were recently combined into the central treatment system (CTS) at WAFB.

The Mission Street pump-and-treat system (PTS) captures GW from the purge wells at the OT024 site, while the FT-02 PTS captures GW from both the former fire training area and the adjacent OT016 site.

For the landfills, Pohlmann said the LF-30/31 PTS captures GW across these two sites.

In terms of additional RA-O systems, he explained that at SS-57, there is a source area biobarrier in support of in situ anaerobic bioremediation (IAB), as well as a downgradient biosparge system.

“We also have an additional biosparge system at the FT-02 site, along with pump-and-treat, and then we’ve got another IAB remedy that is pending for FT-02 and that is to be implemented this spring,” he continued.

As for the LTM activities, Pohlmann said this would include the annual GW sampling of all the IRP sites across the facility. It would also include the yearly GW gauging, which involves more than 400 wells to monitor the water table across the entire site, and its elevations.

“There are also four Military Munitions Response Program sites that are under the contract,” he went on. “These four only receive land use control [LUC] sites. So there, the technical approach is to conduct annual inspections and report on those inspections.”

The LUC sites are comprised of the former bombing and strafing area, weapons storage area, grenade range and EOD range.

In reference to all the monitoring which was mentioned, RAB Alternate Rex Vaughn asked if any water sample testing is being done in these areas.

Pohlmann said yes, and that from the 21 sites, the range of samples they collect is about 350.

“What compounds are you testing for?” Vaughn asked.

“That would be site specific,” said Pohlmann, noting that there are a range of solvents – such as the TCE contamination at LF-30/31 – as well as fuels at some of the other sites.

“So are you testing for PFAS in any of the samples that you collect?” Vaughn questioned.

“We are under contract to test for PFAS at FT-02, as well as part of the treatment monitoring – so, the systems monitoring influent and effluent,” said Pohlmann.

When Vaughn asked about PFAS testing at LF-30/31, “That would not be done under our contract,” Pohlmann said. He explained that this would be carried out with the Wood contract, and now the RI contract being done by the Aerostar firm.

So, Vaughn asked if Pohlmann knew whether these entities have been pulling any PFAS samples up around the two landfills.

RAB Co-Chair David Gibson, of the Air Force Civil Engineer Center (AFCEC), said they were talking about the work of Bay West, but that Aerostar can address Vaughn’s inquiry.

“The quick question is, are you looking at PFAS at those two landfills, in addition to the areas that we’re talking about now?” Vaughn asked.

Gibson answered that the RI for PFAS, which is side boundary to side boundary, will delineate down to the maximum contaminant levels (MCLs) wherever the plume goes. “So that would include those landfills.”

As reported, new MCLs regulating PFAS in drinking water were adopted in Michigan last year for seven types of PFAS compounds. This includes 8 parts per trillion (ppt) for PFOA and 16 ppt for PFOS. The MCLs replace the GW cleanup standard of 70 ppt for PFOA and PFOS.

Pohlmann’s presentation also touched on the remedy implementation and performance monitoring associated with the IAB at site SS-57. Located in the central part of WAFB, SS-57 is the former apron hydrant fuel system site.

“The purpose of our recent activity was to add another component to the existing components in the decision document [DD],” he began, speaking to the supplemental remedy constructed to achieve the RA objectives as specified in the site’s DD.

Pohlmann said that SS-57 is under hydraulic control from the CTS well fields currently, in addition to biosparge having also been historically run at the site to address the fuel constituents there.

The technical approach at this site is to supply nitrate to stimulate anaerobic biodegradation of fuel constituents that are absorbed to the subsurface soil and/or dissolved in shallow GW.

Pohlmann said that fuels like to float, and they tend to make a smear zone along the GW table/soil interface, which is what the Bay West team is trying to attack.

They delivered these amendments (nitrate/phosphate) to the subsurface, via three infiltration trenches at three historical source areas.

“The trenches are about 50 feet long. They are submerged, so we have piping going into the trenches. We flood the trenches, and then that water trickles down into the subsurface and to the water table,” Pohlmann described.

“In between our events, we also conduct performance monitoring, and we’re doing this to kind of assess what the effects are of each injection and to plan future injections thereafter,” he said.

He displayed two images of SS-57, saying that one shows the current or near conditions. “The plumes you can see, these are the fuel constituents.” The image also showed the source areas Bay West is trying to treat, with the concept that if the source areas are treated, then the dissolved plumes will eventually contract.

“On the right hand side we see a cross section of the subsurface,” Pohlmann said of the second figure. “This is actually a historical figure and it depicts soil data that was collected in the 2013 range. But it shows that we have a smear zone just below the water table where we believe this residual contamination resides. And that’s what is maintaining the plumes in the groundwater. So that’s what we’re trying to attack; that depth. And this depth is in the range of 20 feet below the ground surface.”

Pohlmann then shared details of the SS-57 IAB remedy status, to date. Upon installing the trenches and constructing the piping to the surface in September 2019, baseline sampling was conducted that October, so they knew what conditions they started with before the injections.

In the later half of October 2019, the first injection was done. This was followed by the first quarter and second quarter performance monitoring events, where the team was looking at the effects of the initial application.

The second IAB application was carried out in June 2020, after which two more monitoring events occurred – one in July 2020, and another in October 2020. That November, the third IAB application event was completed.

As for the 2021 project schedule at this site, year two of the treatment will convert to semi-annual GW performance monitoring. The first event is scheduled for this spring, most likely in April. Pohlmann said they will then use that information to refine their injection thereafter, with the fourth IAB application potentially taking place in May or June.

To treat the soil, he says, “We anticipate six to seven years of this active remediation, followed by about 20 years of passive natural attenuation monitoring to the point to where we meet cleanup criteria for the entire site.”

According to RAB Co-Chair Mark Henry, this portion of WAFB has a significant amount of BEHP contamination. “And it is probably at your site, as well,” he told Pohlmann. “I’m wondering if you have been doing SVOC [semi-volatile organic compound] analysis, and if your nitrate respiration process has been reducing the concentrations of BEHP.”

While it is sporadic, meaning there is not enough of it to really track trends, Pohlmann confirmed that BEHP has been detected at this site. “I couldn’t tell you whether it has shown up in any of the current/more recent samples.”

“It would be really nice if that type of biostimulation could attack that contaminant, as well,” Henry remarked.

“The current system is not focused on it, but if there’s any kind of co-metabolism there, it’s possible that we’d see that,” Pohlmann said.

While Bay West’s fieldwork at WAFB will end in June, Gibson pointed out that a different firm will be taking this over. AFCEC has awarded the base realignment and closure environmental construction and optimization services contract to LATA-CTI Environmental Services LLC, based in Albuquerque, New Mexico.

Gibson said the contractor will continue all the IRP work at WAFB’s legacy areas which have yet to get site closure.

In reference to SS-57, RAB Member William Gaines wondered which chemicals, specifically, are being injected. “You just called it nitrogen. What’s the composition and specific gravity of that, and why are we essentially putting fertilizer into the environmental remediation?”

He said his understanding is that this is not very friendly to lakes. “Which is where all this is going to end up, as I see the water flow.”

Pohlmann said Gaines is correct that nitrogen is a concern in surface water (SW), and this is taken into account in Bay West’s applications. For instance, just outside of their treatment zones, they’re trying to minimize the concentrations below the allowable SW regulations of 10 milligrams per liter. “And that’s one of the things that we’re evaluating between injections – you know, how far are we exceeding the nitrate concentrations, is it getting beyond our control.”

He also restated that the majority of SS-57 is under hydraulic control from the CTS GW extraction system. “And so we can monitor that, as well. It’s not something that is anticipated or could reach Van Etten Lake on its own.”

“I will say that hydraulic control through the [CTS] is because you’re taking water out of it,” Gaines said. “And you’re right, that water doesn’t go into [VEL]; it goes into Van Etten Creek, which goes into Lake Huron.”

Therefore, he remarked that which body of water it goes into is not really an excuse for saying that that doesn’t make a difference.

“I didn’t mean to suggest that it’s ever going to get to the extraction wells, I’m just saying that’s also a backdrop,” Pohlmann said.

He added that if it ever got to the extraction wells, there would also be a large operation and maintenance problem with the treatment system, because the nitrate would foul up the granular activated carbon which is utilized.

“So by all means, we do not want it to be captured,” Pohlmann said, noting that it is just another component of that remedial system. Further, “The amount of nitrate that we’re putting in is designed to just maintain itself there in the treatment zone.”

Another item discussed at the meeting was a request to the Air Force (AF) from the Need Our Water (NOW) group, which was first reported on in the Nov. 17, 2020 edition of the Oscoda Press and the Nov. 24, 2020 edition of the Iosco County News-Herald.

“We’re well into this, and we’re trying to be patient with the Air Force and with the state, but our patience is waning,” said RAB Member and NOW Co-Lead Cathy Wusterbarth.

She added that they would really appreciate every effort be made to acknowledge the community’s priorities. One such priority is the VEL plume, which NOW has asked the AF to address in its entirety.

As reported, the group sent a letter to the AF last October, requesting that the proposed F-41 extraction well field be extended by about 1,500 to 2,000 feet to the north, to capture the entire plume.

“We did receive a response on that, although, the response was not definite,” according to Wusterbarth.

As noted in last week’s edition, an update on the status of the PFAS RI at WAFB was given by Paula Bond of Aerostar. She shared the schedules of the RI and interim remedial action (IRA) processes, for which the RI document is still in the project planning phase.

For the VEL IRA at Ken Ratliff Memorial Park, Bond said at the time of the meeting that the 90 percent design phase was currently under AFCEC review.

Prior to that presentation, Wusterbarth said that since the plans for this plume are 90 percent done, she was hoping the AF could address that at the meeting.

Following Bond’s synopsis, Wusterbarth again said that she and others are wanting an answer as to whether the NOW proposal will be considered.

“The letter, I believe, said it would be considered, and you’ll be seeing the proposed plan and the design for the IRA with what we end up doing,” said Gibson, who sent the response to the NOW correspondence.

“So it was considered and it will be included?” Wusterbarth asked.

“It was considered and we’re still working on the final answer,” Gibson replied.

NOW member and VEL property owner, Anthony Spaniola, penned the October 2020 letter to the AF on behalf of NOW. It was during the public comment period of the RAB meeting when he asked for some clarification, based on what was said that night.

His understanding, he shared, is that the extension of the extraction well line proposed by NOW is being considered for the IRA. But he wanted to make sure, because the letter from the AF seems to indicate that this is not going to be considered until the RI stage.

An individual, who did not state her name or agency, told Spaniola that this is something which should be considered once they get into the feasibility study. Right now, the biggest thing that the IRAs are trying to do is to ensure capture.

“That’s the whole point of our comment – that you’re not capturing enough of that plume. So I don’t understand that,” said Spaniola.

Gibson said that goes back to an interim action to capture the hot spot. “And then there’s going to be an IRA that fully delineates PFOS/PFOA and the risks, and then a feasibility study developing the long-term solution.”

“So what you’re saying is, the request to have this as part of the IRA has been turned down?” Spaniola asked.

“I would like to finish the proposed plan before answering that question,” Gibson said.

“It sounds like, from the comment and from the letter that was sent to me, that that decision’s already been made,” Spaniola continued. “Is that true?”

Gibson said he would like to defer to the proposed plan after review with the Michigan Department of Environment, Great Lakes and Energy (EGLE). “Is that acceptable?”

Spaniola reiterated that it is important to the community that this extension be done now.

He said there was a reference in the AF letter to the fact that temporary monitoring data was not going to be considered. “In speaking with our technical people, that is not an appropriate way to deal with a situation like this.”

Since this is the number one priority of NOW, he again asked that this be done right away. “This is the time to do it because it’s economically feasible. And I think it would be a mismanagement of funds to put it off to a later date.”

In related topics, former RAB member Robert Delaney said that, although it’s plausible it has not gone under VEL, it’s hard to imagine another source explaining the large plumes on the east side of the lake.

He also said he believes it is it the AF’s responsibility to fully characterize that plume. “The assumption that it all discharges into the lake is not proven, and it can be proven if you put the effort into it.”

Bond said that in the conceptual site model (CSM), they have evaluated all of the data that they can put their hands on which has been collected regarding the lake and the river. “And our technical team feels strongly that there isn’t movement of the plumes under the lake. So that information will be presented in the CSM.”

Bond said this may change if they find something else during the RI. “But, based on all the data that we and EGLE have collected to date, and everyone else that’s been out there, we feel strongly that there is no movement and that it’s not necessary at this point.”

According to Gaines, community members feel there is no other plausible explanation for the level and extent of the PFAS contamination on the east side of VEL, and he added that there certainly needs to be more investigation.

To access the link to the meeting recording, visit the AFCEC website at https://www.afcec.af.mil/Home/BRAC/Wurtsmith.aspx and click on the “RAB Meeting Materials” tab.

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