Four more city wells show trace levels of PFAS chemicals

Thursday, May 16, 2019 - 11:01am

Madison Water Utility has been conducting advanced testing of the city’s 23 water wells looking for a class of chemicals known as “PFAS.” New results show that four more city wells may have trace amounts of the chemicals. That brings the total number of wells where PFAS have been detected to ten. Nine wells have been found to be clear of all thirty PFAS tested.

Most wells with PFAS detections show trace amounts of a mixture of several types of the compounds, many of which are at levels too low to accurately measure. Madison Water Utility water quality manager Joe Grande cautions that results at two wells, Well 7 on N. Sherman Ave. and Well 29 on N. Thompson Dr., may be false positives. Testing labs reported levels of less than a half-part-per-trillion at those wells.

“Something below a part-per-trillion or half-part-per-trillion can be suspect. We are reporting that as a detection, but that could be an artifact of the method itself,” says Grande. “We’re more confident in the levels reported when they are two parts-per-trillion or higher.”

PFAS (or per- and poly-fluoroalkyls), are a widely-used class of chemicals found in non-stick cookware, water-resistant clothing, upholstery, carpeting, food packaging and firefighting foams. Thousands of types of PFAS compounds have been manufactured and many are still being used. The EPA has established a Lifetime Health Advisory Level for two types (PFOA and PFOS) of 70 parts-per-trillion. High levels of PFAS exposure have been linked to a variety of health concerns, including increased risk of some types of cancer. According to Public Health Madison Dane County, current levels of PFAS detected in Madison wells are not considered a threat to health.

The latest test results show traces of the compounds at some wells located in residential neighborhoods, far from expected sources like airports, landfills and manufacturing sites. PFAS have been detected in wells on both the east and west sides of the city.

“These chemicals are not well-understood at this point in terms of where they’re coming from,” Grande says. “We are finding PFAS at the well closest to the airport where firefighting foams have been used. That seems logical. There was a logical conclusion that’s been drawn there. And now, that’s kind of been turned on its head,” Grande says. ”Airports and landfills are clearly not the only sources of PFAS in our environment.”

Madison Water Utility tested all city wells for PFAS in 2014 and 2015 but found no sign of the chemicals. Two years ago, the utility began using new, more advanced testing methods capable of finding trace amounts in water down to less than one part-per- trillion. It targeted wells near the airport and old landfills and detected PFAS in two of those wells. This year, the utility is not only testing all 23 city wells using the advanced methods, it’s also screening for more types of PFAS chemicals.

“Analytical abilities have only recently allowed us to detect PFAS at these really, really low levels in water,” says Grande. “I think that there’s a lot of value in the known versus the unknown, and our customers deserve that information.”

So far, PFAS are not regulated under the Safe Drinking Water Act and most water utilities in Wisconsin are not currently testing for the chemicals.

The utility plans to test its final four wells, which are operated seasonally during high-demand warm weather months, when those wells are started up this summer. Grande says based on results so far, he would not be surprised to find very low levels of PFAS at one or more of those wells.

Find more testing result information on Madison Water Utility’s PFAS Testing and Information page.

Wells with PFAS detections:

Low Level Detection
Well 15 E. Washington Ave.
Well 9 Spaanem Ave.

Trace Detection
Well 6 University Ave.
Well 7 N. Sherman Ave.
Well 13 Wheeler Rd.
Well 14 University Ave.
Well 11 Dempsy Rd.
Well 16 Mineral Point Rd.
Well 26 High Point Rd.
Well 29 N. Thompson Dr.

Wells with no PFAS detected:

Well 12 S. Whitney Way
Well 18 Park St.
Well 19 Lake Mendota Dr.
Well 20 Prairie Rd.
Well 24 N. Livingston St.
Well 25 Queensbridge Rd.
Well 28 Old Sauk Rd.
Well 30 Moorland Rd.
Well 31 Tradewinds Pkwy.

Wells to be tested this summer:

Well 8 Lakeland Ave.
Well 17 S. Hancock
Well 23 Leo Dr.
Well 27 N. Randall Ave.

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