David Michael Miller
Madison Well 9
Seven PFAS chemicals were found in Well 9 at a concentration of 38 parts per trillion, the highest amount in the city.
The Madison Water Utility announced in its most recent annual Water Quality Report that drinking water in the city meets federal and state health and safety standards. But the utility still found PFAS chemicals in nine of the city’s 21 wells, and a 2022 health advisory from the Environmental Protection Agency questions whether exposure to these chemicals, known as “forever” chemicals, is safe at any amount. This is Madison’s first water quality report since the EPA’s advisory.
PFAS, synthetic chemicals used in everything from food packaging to firefighting foam, do not break down easily in nature or the human body due to their strong molecular bonds. According to the city’s May 12 report, the highest combined concentration of PFAS chemicals was found in Well 9, which serves Madison neighborhoods south of Cottage Grove Road. There, PFAS chemicals were found in concentrations of 38 parts per trillion. Well 11 serving the east side of Madison had the second highest concentration of PFAS chemicals measured, at 14 ppt, and Well 6, serving the near west side and UW campus area, was measured at 12 ppt. In 2019, a well serving the east side that was found to have concentrations above 55 ppt was shut down while a PFAS treatment facility is being constructed; the facility is expected to be completed in 2025.
In March, the EPA proposed a binding rule that would significantly lower the maximum contaminant level for the two earliest and most studied PFAS chemicals, called PFOA and PFOS, to just 4 ppt, “the lowest feasible level based on the ability to reliably measure and remove these contaminants from drinking water.” Wisconsin’s and the EPA’s current standard for the chemicals is 70 ppt.
“We’ve detected PFOA and PFOS in about half of our wells, and we detect that it’s very low level, generally around one part per trillion,” says Joe Grande, the water quality manager at Madison Water Utility. Grande says that the Wisconsin State Laboratory of Hygiene, which conducted some of Madison’s PFAS measurements, can detect down to a concentration of 2 ppt while some private labs that also conducted tests can do so down to a concentration of 0.5 ppt. The concentrations are so small that at Well 8, a seasonal well on the east side where PFOA and PFOS were found in 2021, the chemicals were not found this year because the lab’s detection limit was too high.
But according to the EPA, “there is no level of these contaminants that is without a risk of adverse health effects.” The EPA advised last year that the safe concentration for long-term exposure to PFOS is just 0.02 ppt. For PFOA, it’s even lower. These levels are so low they can’t currently be measured, leading Grande to call them more of a “qualitative guideline” that any long-term exposure to the chemicals carries a risk of adverse health impacts.
While the five Madison wells with measurable PFOS would not trigger regulatory action, the concentrations found still exceed the EPA’s advisory level dozens or hundreds of times over.
“The EPA has said there is likely some health risk for that consumption, and it would be up to the individual to do more to treat their water,” says Grande. Even if water with such small traces of PFAS were treated at the well, says Grande, it wouldn’t be possible to measure that the treatment had worked and reduced the chemicals’ presence to the desired level. Grande says that while activated carbon, charcoal and reverse osmosis are ways to reduce organic contaminants in drinking water at home, including PFOA and PFOS, products that use those techniques are often only certified to the EPA’s current standard — 70 ppt.
Elsewhere in the city, other wells had small combined PFAS measurements too. On the far west side, Wells 16 and 26 had concentrations of 6.7 and 4.6 ppt, respectively. Well 14, which provides water to the Regent, Spring Harbor, Sunset Village and Old Middleton Greenway neighborhoods, measured 8.4 ppt. Well 13, on Madison’s north side, also measured 8.4 ppt. Well 27, which serves areas near campus, measured 5.3 ppt. Well 7 in the Tenney and Marquette neighborhoods measured 2.7 ppt.
Grande says that the utility is also keeping its eye on a lesser-known PFAS chemical known as PFHxS. The EPA’s new regulation sets a maximum contaminant level for the chemical at 9 ppt, or lower if certain other PFAS chemicals are also present. In Madison, Well 6 on the near west side near the UW campus measured PFHxS at between 5 and 6 ppt, and Well 14, also on the west side, measured levels above 4 ppt. If the EPA lowers the maximum contaminant level of PFHxS in the future, those wells could require treatment. Madison’s wells will be tested for PFAS chemicals twice this year, the first round of which has just been completed.
You can find out which wells serve your address here. You can find a breakdown of the report’s measurements of 29 individual PFAS chemicals at each of the city’s wells here.
