The history of contamination at Truax is discussed by Maria Powell here. As with many sites contaminated with PFAS by use of fire fighting foam, there is a previous investigation of contamination by chlorinated volatile organic compounds (CVOC or VOC). Madison municipal well 15 was equipped with an air stripper to remove them. The big picture is displayed in her map. It does not include the affected municipal wells, which are discussed below under heading Receptors.
What we know as of 4/2022
Mistakes we've seen (well, besides at least a decade of foot-dragging)
- Primary documented impacts are on Madison municipal well 15 along with Starkweather Creek, Lake Monona and the Yahara River down to the Rock River.
- Madison Water Utility instituted PFAS annual testing in 2019 and will be going to semi-annual.
- DNR sampled Starkweather Creek (worst in the state by far) and Lake Monona (fish included), then issued a fish advisory downstream along the Yahara River to the Rock River.
- Dane County's retired burn pits have had their phase I sampling.
- Airport storm sewer system outfalls and a few major junctions have been sampled and sections near the WIANG base had a video inspection. Repairs to prevent infiltration of PFAS contaminated groundwater are projected for 2022.
- WI Air National Guard (WIANG) completed their phase 1 site investigation and in 12/2021 submitted a workplan for the main site investigation with field work to begin in spring 2022, conducted by EA Engineering and Technology's Omaha office.
- The WIANG investigation will use a screening level of 40 ppt, based on the 2016 EPA health advisory level of 70 ppt. EPA toxicologists have indicated they consider this level far too high to be protective. If the screening level is taken literally, work to determine the extent of the groundwater plume will stop far short of municipal well 15.
- At the 1/11/2022 site investigation open house, Bill Myer of the National Guard Bureau (funder for the site investigation) stated that they would consider state regulations, but only if they had been promulgated. While DNR staff had proposed a more protective groundwater standard, the DNR board refused to pass it along to the state legislature which would likely have spiked it anyway.
Things we strongly suspect but which have not yet been confirmed
- Dane County's initial attempt at an interim stormwater treatment failed because their contractor ignored engineering best practices.
- Local attempts to use groundwater models to locate sources of contamination have not considered surface transport and the models underestimate the distance that PFAS can move in the groundwater.
- In addition to well 15, wells 9 & 23 east of Lake Monona are likely contaminated by PFAS from Truax. This is the result of Starkweather Creek carrying PFAS downstream to a location where it can leak into the groundwater. There is one private well adjacent to the creek which has tested over the DNR recommended standard, consistent with behavior at the 3M disposal site in Oakfield, MN.
- PFAS composition in all wells is consistent with AFFF. Madison Fire Department has been using it roughly five times per year to extinguish vehicle fires. It logically tends to travel through the stormwater network. Patterns in the well data on the west side are what you might expect from that.
- The groundwater plume from the WIANG base is expected to move southeast until is reaches the capture zone of well 15 where most of it seems to disappear because it was being distributed by the water utility until the well was shut down. Around the beginning of 2022 the utility announced it would not operate well 15 while it remains above the DHS hazard index. At last testing it as 15% over. They did a pilot study in 2020 and found treatment was expensive but feasible. On 4/26 the water utility board voted to approve a contract with AECOM for engineering services to design and implement a treatment system for well 15. The normal bidding process was bypassed in order to meet an application deadline for bipartisan infractructure funds administered by the WI DNR.
02-13-581254 WANG-115TH FIGHTER WINGDocumented Routes Off Base
20211223_35_SIWP2.pdf PDF p. 80 fig 10-8
Soil and groundwater results for the Air National Guard base only - does not include old burn pits on Darwin Rd & Pearson St (see below)
original documents20170831_35_SIWP.pdf site investigation workplan02-13-583366 DANE COUNTY FIRE TRAINING AREAS
samples taken 11/08/17
20190711_37_SIR.pdf Final Phase I site investigation report (Amec Foster Wheeler 2019) and are summarized in
results displayed in a map on PDF p. 80 - 85, Figs 4-9
20200306_35_SIWP.pdf site investigation workplan for Darwin and Pearson burn pits.
20201215_120_PFAS_Sampling_Completed.pdf Former Firefighting Training Areas Soil and Groundwater Sampling Summary, Mead & Hunt, Inc./LimnoTech dated 11/2020
PDF file pp 7-10, Figures 1 through 4 show reported PFOA and PFOS results for soil and groundwater samples
Via groundwater to well 15
This situation is reminiscent of Oakfield, MN municipal well 5, the well most heavily contaminated by the 3M disposal site, discussed in detail in this chapter.
Through the airport storm sewer network to Starkweather Creek
The current theory is that a shallow groundwater table allows highly contaminated groundwater to infiltrate into the storm sewers which carry it to outfalls in the branches of Starkweather Creek that drain the airport
ReceptorsIn the stormwater chapter I have summarized the testing in Starkweather Creek and Lake Monona, at the storm sewer outfalls and at a few major junctions in the storm sewer network. In May 2021 there was an extensive video inspection of the storm sewers in the area around the WI Air National Guard (WIANG) base. I also did an engineering critique of local efforts to operate a filter intended to remove PFAS from the stormwater.
Through the food chain via fishSite Investigation Workplan Summary
In June 2021 the fish advisory for Starkweather Creek, Lake Monona and the Yahara River was extended to the Rock River.Madison Municipal Wells (and a few private wells)
After a lot of pushing from local environmental activists the Madison Water Utility tested all of its wells in 2019 and has done so annually since. In this chapter I (mostly) used the 2020 numbers to examine the composition of PFAS across the wells, concluding that it is consistent with AFFF. Three of the wells appear to be impacted by Truax. The others may well have been contaminated by the Madison Fire Department which for decades has used foam to extinguish vehicle fires. I reference separate chapters suggesting that surface water transport is important in spreading PFAS more widely within the city, and explaining why the usual groundwater models are inadequate to estimate the extent of PFAS groundwater plumes and inversely to locate their source.
In 2020/2021 the utility contracted for a PFAS treatment feasibility study. They initially proposed to wait on the well 15 decision until DNR promulgated standards. After community feedback they modified their stance, stating that they would use the stricter WI DHS hazard index which takes into account PFAS other then PFOS & PFOS and which well 15 exceeds. In the Town of Campbell near the La Crosse airport anyone with a DHS hazard index > 1 gets bottled water.
There are systemic issues that should be addressed. The water utility technical advisory committee lacks PFAS expertise. Public input consisting of a utility-wide 'info' email address which elicits no response is insufficient.
Public messaging by the city should make less use of trite phrases like 'speak with one voice' and more discussion of the published toxicology research that underlies attempts to set health levels.
On 1/11/2022 the National Guard Bureau gave an 'open house' presentation of the workplan, which is available on the DNR BRRTS page titled 02-13-581254 WANG-115TH FIGHTER WING. The workplan is split into three documents, including 20211223_35_SIWP2.pdf (information specific to Truax) and 20211223_35_SIWP.pdf (information common to all three sites covered by the contract).
The goals as stated in 20211223_35_SIWP2.pdf include:
2280 • Determine the extent of PFAS at or above RI [remedial investigation] SLs [screening levels] (Worksheet #15) at sources and in allThe most important takeaways consist of the list of specific contaminants considered and the screening levels at which they are considered significant.
2281 pathways at Truax Field.
2285 • Determine the concentration of PFOA, PFOS, and PFBS at or above SLs
2286 (Worksheet #15) in soil, groundwater, surface water, vadose zone porewater, and
2287 sediment, both in source areas and all pathways, to establish concentration gradients.
1972 The quantitative human health risk assessment will be limited to three of the PFAS—PFOS,
1973 PFOA, and PFBS—for water samples (groundwater and surface water) per U.S. Air Force
1974 guidance. Additional PFAS may be included in the assessment if toxicity values become
1975 available during the project.
20211223_35_SIWP.pdf PDF p. 41 (ca line 982)
QAPP Worksheet #15-1: Project Screening Levels and Laboratory-Specific Detection/Quantitation LimitsThese screening levels are well above the WI DHS proposed health levels. The most contaminated municipal well along with the contaminated private well would not merit consideration. This is true even though EPA toxicologists have recently signaled that this level is inadequate.
Analyte Acronym CAS SL (ng/l)
Perfluorobutane sulfonate PFBS 375-73-5 600
Perfluorooctane sulfonate PFOS 1763-23-1 40
Perfluorooctanoic acid PFOA 335-67-1 40
note: no screening level for PFHxS
At the 1/11/2022 Open House, Environmental Restoration Program Manager Bill Myer stated that state regulations would be considered, but only if they have been promulgated. That is very unlikely given the level of control that WMC has over both the DNR board and the state legislative committees.
While the site investigation is unlikely to define the full extent of the contamination, it will generate considerable information regarding the source areas and suggest how it is entering Starkweather Creek.
The consultants made some observations about the conditions at Truax and how they might influence PFAS transport off the base
1883 10.10.1.2 Truax Field-Specific Fate and Transport ConsiderationsIn addition, if the groundwater flow is indeed toward the southeast it seems likely that the contamination is being carried away from Starkweather Creek, toward well 15. These factors raise the possibility that the storm sewers are the primary route for contaminants to enter Starkweather Creek, and that the proposed repairs might result in a large reduction. We can only hope.
1885 • The presence of organic-rich marshy deposits has particular significance for retention of
1886 PFAS mass in source areas.
1888 • PRLs 1, 2, and 3 are on the western portion of Truax Field and located closest to potential
1889 surface water migration pathways. Additional potential sources identified in Sections
1890 10.9.2 and 10.9.3 are also located near potentially downgradient surface water migration
1915 • The shallow depth to groundwater at the Base, presence of marshy deposits, and low
1916 permeability of underlying glacial deposits are good indicators that vertical migration
1917 pathways for the plume may be limited. However, historic maps indicate that the marshy
1918 deposits are absent in potentially downgradient directions.
The gory details of the geology and methods will mostly be pushed into a separate chapter but there are some highlights worth listing here.
It may be best to start by looking at Fig 17-1 thru 17-8, which start on p. 112 of the PDF file 20211223_35_SIWP2.pdf:
Figure Discussion page no.The sampling approach is discussed on PDF file p. 103 (line 2813). The term 'transect' will be discussed in the geology & methods chapter. The two paragraphs beginning at line 2833 merit an explanation here.
17-1 transects 88, 103-106
17-2 crash site 104, 105
17-3 surface/storm/sediment samples 90, 106
17-4 background samples 104
17-5 PRLs 4, 5, 6 104
17-6 PRLs 8, 9 104
17-7 PRLs 1,2, 3, 7*** 104
17-8 PRL 10 104
***note that PRLs 1-3 are the fire station and its associated nozzle test areas, the most contaminated part of the base
2833 Data generated during the RI will be a combination of definitive analytical results and"Definitive analytical results" are generated by shipping samples to a traditional laboratory. "Quantitative screening analytical results" are generated by processing samples on-site in a mobile laboratory. The mobile lab is the result of a SERDP/ESTCP project, the results of which were published.
2834 quantitative screening analytical results.
The mobile lab achieves rapid sample throughput both by eliminating shipping delays and by using a reduced set of PFAS analytes, basically the three compounds for which screening levels are established. This allows for high resolution plotting of the plumes and quick decisions in the field on where to sample next. When a particular sample requires a more accurate determination for comparison with a screening or health limit or if a full set of analytes is desired, part of the sample is shipped to the traditional laboratory. There is further discussion of the mobile lab on PDF file p. 162.
PDF p. 95 (line 2543) is the projected work schedule
It is also worth noting that the consultants propose to use the TOP assay on a subset of samples, mentioning it at lines 2340 [soil], 2438 [unspecified] and 2882 [soil].
This should provide an upper limit for the amount of precursors which do not show up in the analytical results discussed above.
Jennifer Field has noted that quadrupole time of flight (QTOF) analysis of samples from AFFF sites show "missing mass", usually only 10-15% of the total but occasionally up to a third.
In my comments on the workplan I noted that well 15 has several characteristics which suggest the presence of significant precursors and recommended a TOP assay on the groundwater in the plume.
Lines 2340 and 2882 say that the TOP assay will be used for a subset of soil samples. Line 2438 also mentions the TOP assay but is ambiguous as to which media are involved.
Well 15 has multiple characteristics that suggest the presence of precursors:
Significant levels of undetected precursors could result in underestimation of effective PFOS+PFOA levels. For this reason some have recommended use of the TOP assay for drinking water to “quantify presence of perfluoroalkyl compound precursors in the supply”.
Understanding the Uses and Limitations of TOP Assay for PFAS Monitoring in Drinking Water- Rebecca Slabaugh referenced in
PDF p. 33 (line 703) discusses previous investigations, which are listed in worksheet 13 on PDF p. 93 (line 2518).
PDF p. 106 line 2961 storm sewer (references fig 17-3)
table 17-1 summarizes results of video examination of sewer condition
PDF p. 21-31 lists the organizations and personnel involved in the site investigation
The division of responsibilities is awkward because the DNR has identified three responsible parties:
- Wisconsin Air National Guard (WIANG) 115th Fighter Wing which hosts the airport fire station. The National Guard Bureau is funding the WIANG base site investigation. Bill Myer is their primary contact. He manages projects in several states. The US Army Corps of Engineers (USACE) Omaha office is apparently managing the technical aspects of the contract. EA Engineering and Technology (Omaha office) is the primary environmental consultant.
- Dane County owns the airport property and uses the WIANG fire station to respond to commercial and private emergencies and has historically operated burn pits used to train fire fighters. Dane County has taken responsibility for the contaminated stormwater and for the site investigation at the old burn pits.
- City of Madison has trained its fire department at the airport. It is also host to the vast majority of the people impacted by the contamination.