Photo of smoke plumes over Lake Monona from MGE and UW campus transformer fires, July 19, 2019. How much PFAS was in this smoke–and how far did it travel?



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The Wisconsin State Journal reported on August 8, 2019 that low levels of highly toxic per and polyfluoroalkyl substances (PFAS) were found after the July 19 MGE transformer fire in downtown Madison. The PFAS compounds were from aqueous film-forming foams (AFFF) used to extinguish the fire by the Madison Fire Department and Truax Air National Guard firefighters. [1]

PFAS levels found at the site, in fact, were not “low.” Tests at the site the day of the fire, after firefighting activities were completed, found up to 890 parts-per-trillion (ppt) of fifteen different PFAS compounds combined . Five days later, on July 24, consultants took a sample of shallow groundwater from where a damaged power pole was removed at the site and found a total PFAS level of 5604 ppt .[2] This data was not available to the WSJ for the August 8 story. According to the Sept. 9 consultant’s report, this water was “ representative of shallow groundwater conditions on site within a week of the incident .” (see pgs. 3-4 of the report, under b. i. North Power Pole; the data for this sampling point is in the table on pg. 12 of the report).

The Wisconsin Department of Health Services recently proposed a groundwater standard of 20 ppt for two types of PFAS–PFOA and PFOS (combined). The level of these two compounds in the shallow groundwater under MGE was 55 ppt. The level of just one unregulated PFAS compound, 6:2 FTS, was 4900 ppt. [3]

PHOTO: Firefighters spraying foam on the MGE transformer fire, July 19, 2019 (from Wisconsin State Journal)

Not to worry, says DNR! PFAS didn’t make it to Lake Monona or Yahara River



The groundwater on the Isthmus—a former wetland—is shallow and sloshes around in stormdrains leading to Lake Monona and the Yahara River. The August 8 WSJ story stated that, according to DNR, “[t]here were no samples taken where the storm sewers empty into the Yahara River and Lake Monona” and “there was no indication that the materials made it that far and that concentrations would likely be lower than those near the site.”

Actually, samples had been taken from storm sewers emptying into the lake on July 25, about a week after the incident. These tests found: 568 ppt PFAS in a catch basin near the site draining to city storm sewers; 99, 105, and 115 ppt in the stormwater pipe from MGE to the lake (along Blount Street); 92 ppt where this pipe discharges into Lake Monona (1/3 mile from the site); 59 ppt at a storm outlet in Law Park (almost ½ mile from the site); 1 8 ppt at the corner of S. Livingston St. and E. Washington (near MGE) and 15 ppt at the storm sewer outlet to the Yahara River (over a mile from the site).[4] Here’s a rough map of most of these PFAS test locations.

These PFAS tests were very limited. They were only one-time tests, one week after the event, and only from water. Based on published scientific research (see pg. 5 of this paper), if sediments at the outfalls are tested (especially over time as more sediments are deposited from runoff from the site into the storm drains), levels will likely be higher and include more of the longer chain PFAS such as PFOA and PFOS).

The DNR representative who talked with the State Journal on Aug. 8 may or may not have known about this PFAS data at the time, because it wasn’t included in the July 30 report available then. The storm drain and storm outlet data, as far as we can tell, first appeared in the Sept. 9 report posted on the DNR BRRTS site, and MEJO discovered it on Sept. 24.

What about anglers? Did anyone warn them?

The Blount Street storm drain discharges into Lake Monona under a small pier next to the Elks Club. Many people, including minority subsistence anglers, fish from the pier there. Boat anglers also fish nearby.

Photo below: The Blount Street storm drain pier on Sept. 25. Is the 6 inch high surface boom for capturing PFAS runoff? If so, it seems completely inadequate…

Just several hundred feet to the northeast of the Blount Street drain is a large cooling water pipe from MGE that travels under Livingston Street and then discharges from a giant outlet into the lake. Fish congregate in the strong warm water current from this drain—and so do boat anglers who know that the fishing is great there.

Shoreline anglers—including many people of color—also fish in Law Park where PFAS was discharged.

Photos below: Stormwater outlet at the north end of Law Park.

Photo above: The 6 inch high yellow boom is presumably for keeping PFAS out of the lake–NSEC stands for North Shore Environmental Construction, one of the contractors hired to do the cleanup at the site.

PFAS can concentrate in fish to levels thousands of times above levels in the water (see studies here). The MGE discharges of PFAS occurred in high fishing season, which goes through the fall and for ice anglers, into the winter.[5]

Though some efforts were made to contain stormwater PFAS discharges from the site on the day of the fire, they were only put in place hours after the highest PFAS releases–and these stormwater control measures can’t fully contain the discharges. Given this, significant quantities of PFAS were likely released into the lake in July—and probably still are leaching from the contaminated soils and shallow groundwater at the site and along the storm drains.

How much PFAS are anglers who fish in Lake Monona, especially near the Blount Street and Law Park outlets, ingesting when they eat their catch?

What are the PFAS levels near the Blount Street and Law Park outlets now? Will anyone test the sediments or fish?

PFAS compounds discharged from the Blount Street and Law Park stormwater outlets included a mix of longer carbon chain and shorter carbon chain compounds. Those with shorter chains, which are highly mobile in water, likely traveled far out into the lake. Longer chain compounds, on the other hand, are more likely to attach to lake sediments and build up closer to the outfall, moving around to some extent with sediments as they slosh outwards from the outfall into the lake.

PFAS compounds are known as “forever chemicals” so they will remain in sediments there for decades to come and continue to cycle through the aquatic food chain.

What’s next? Does anyone care about people who eat the fish?

American Transmission Company (ATC), which DNR considers the “responsible party” (RP) in this case, is required to follow DNR regulations including NR 716.

NR 716 requires that the RP perform a field investigation that includes an evaluation of potential pathways for migration of the contamination and impacts on “receptors,” consideration of known or potential impacts of the contamination on resources affected by the contamination, evaluation of surface and subsurface rock, soil, and sediment characteristics to understand how the contamination might travel, investigation of the extent of contamination in the source area—and, importantly, “ the extent, both vertically and horizontally, of groundwater contamination.”

Madison Water Utility drinking water Wells 17 and 24 are very close to MGE—so understanding the width and depth of the plume is critical.

The Aug. 8 DNR letter stated that “The Department requests that by August 23, 2019 ATC submit a site investigation workplan” that addresses the above components. However, the Sept. 9 report notes that “WDNR in subsequent email correspondence agreed that the Work Plan submittal may be delayed until the spill cleanup activities are completed and the laboratory reports from soil and water samples collected during the cleanup have been received.” How long will this take?

Meanwhile, Lake Monona anglers continue to catch—and many will eat—fish that is very likely to be PFAS contaminated. Does anyone care?

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[1] The American Transmission Company (ATC) owns the transformer and is responsible for cleaning up the PFAS.

The manufacturer of the fire-fighting foam used (“FireAde”) told the Madison Fire Department that it had only one type of “environmentally-friendly” PFAS in it—an assurance that was repeated in the city press release about the incident and the initial media coverage on the incident. The PFAS the manufacturer said was in the foam, PFHxA, is not “environmentally friendly.” There are fewer toxicity and other risk studies on this compound, but that does not deem it environmentally friendly. In fact, an increasing number of studies are showing that the shorter chain PFAS compounds like PFHxA and 6:2 fluorotelomer sulfonate used to replace PFOA and PFOS are as or more toxic than the longer chain compounds and are more mobile in the environment.

[2] The majority of the PFAS found in these samples was 6:2 fluorotelomer sulfonate (FTS), a shorter chain PFAS that replaced PFOA and PFOS in many firefighting foams.

[3] These groundwater standards do not apply to stormwater or surface water. The consultants report correctly noted that “At this time there are currently no surface water standards being proposed. As a proposed groundwater standard, the ES and PAL do not apply to our surface water or storm water results.” Michigan has surface water standard for PFOS alone of 11 ppt, in part to prevent the buildup of harmful levels of PFOS in fish. Several of the areas tested at MGE and offsite had PFOS levels higher than this.

[4] On August 6, more samples were taken from trench excavations on site and tanks that stored water removed from sewers. We could not find the data from these samples in the reports. A wastewater treatment plan includes some data from the tanks—5385 ppt PFAS (but this only includes five PFAS).

[5] In the winter, people ice fish in Lake Monona, though they can’t fish near the MGE Blount discharge drain because the warm water coming from it keeps the ice from freezing in a large area near there.

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