Deep freeze delays water testing at East Side well

Friday, January 25, 2019 - 12:57pm

Madison Water Utility has delayed testing at an East Side well for PFAS (or per- and poly-fluoroalkyls), widely-used chemicals found in food packaging, non-stick cookware, stain-resistant fabrics, and firefighting foams. The utility had hoped to collect samples for its first round of monthly testing today or early next week, but it has delayed the move because of extremely cold temperatures. The water samples must be sent to an out-of-state lab for analysis, creating a risk that the samples could freeze in transit. If a sample freezes, it will be thrown away

“The small volume of the sample that’s collected introduces a greater risk of the sample totally freezing,” says Madison Water Utility water quality manager Joe Grande. “When they freeze, it changes the chemistry of the water, and it can impact the ability to detect and accurately quantify the contaminant.”

Madison Water Utility hopes to move forward with testing once overnight temperatures are above 20 degrees.

According to Public Health Madison Dane County, low levels of PFAS detected so far at the East Washington Ave. well, known as Well 15, are not considered a threat to public health. City officials believe the chemicals are likely coming from nearby Truax Air Field, where PFAS were found in shallow groundwater and have been used in firefighting foams.

PFAS are not regulated in drinking water, but the EPA has set a Health Advisory Level for two types of the chemicals (PFOA and PFOS) at 70 parts per trillion. The level of those chemicals at Well 15 is 10 parts per trillion.

Expanding testing

Madison Water Utility decided to ramp up testing from quarterly to monthly in order to gather more data about whether PFAS levels at the well are changing. October tests showed a 5 part-per-trillion increase from tests run in March of last year.

“We want to see if that’s just variability in the test method, or if that’s some type of increase that we’re seeing,” Grande says.

Grande also plans to test for more types of the chemicals. Samples will be sent to two different national labs. One will look for 24 types of PFAS, the other will look for 30. The testing is not required under state or federal regulations, and only a limited number of labs across the country can reliably carry out the expanded tests at such low concentrations.

“The Department of Defense has a list of 24 contaminants that they’re typically testing for, and they have an accreditation process for labs that can satisfactorily quantify those 24 PFAS chemicals,” Grande explains. “The plan is use two labs at least this one time, and see how the results compare. If they’re really highly variable between the two labs, we might want to do two tests again.”

Grande notes the testing focuses on PFAS types that were the most widely manufactured and most commonly used in commercial applications like firefighting foams and nonstick and anti-stain materials.

Expecting to find PFAS precursors

So far, six types of PFAS chemicals have been found at low levels at the well, with a total concentration of just over 40 parts per trillion. Grande expects these new tests will detect trace amounts of chemical precursors for some types of PFAS.

“Firefighting foams contain a mixture of PFAS chemicals, and some of the chemicals are not completely formed – they’re called precursors. Our tests this time around will be looking at some of those. When I talk to folks at one of the labs, they feel like these precursors are going to be present. If you find PFOA, PFOS or PFHxS, you often find precursors with them. So we shouldn’t be surprised if we find some of these.”

Madison Water Utility will be presenting information about PFAS at its next Water Board meeting, set for 4:30 p.m., Tuesday, January 29th at 119 East Olin Avenue. The public is welcome to attend, comment, and ask questions. The utility has also reached out to neighborhood groups in the East Washington Ave. area about presenting information at neighborhood association meetings. You can find out whether Well 15 serves your address and view detailed testing plans by visiting Madison Water Utility’s PFAS information page.


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