DNR: Starkweather Creek has high PFAS concentration

Starkweather Creek in Madison.
Starkweather Creek in Madison.(NBC15)
Published: Oct. 7, 2019 at 1:34 PM CDT
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Elevated levels of PFAS chemicals has been found in two Wisconsin waterways, including one in Madison.

On Monday, the Wisconsin Department of Natural Resources announced they received the first round of per- and polyfluoroalkyl substances (PFAS) surface water sampling results from the State Lab of Hygiene.

The results shows elevated levels of PFOS, one of the most widely used and studied PFAS chemicals, in Starkweather Creek in Madison and Silver Creek in Monroe County. Lower levels of contamination were found in other waterways. The highest concentrations tended to occur downstream of known contaminated sites and in smaller streams with low flow.

The West Branch of Starkweather Creek near Fair Oaks Avenue had the highest concentration of PFOA at 43 parts per trillion (ppt) and PFOS at 270 ppt. One of the sources near the creek is at Truax Field Air National Guard Base, where PFAS containing fire-fighting foam was used.

According to the DNR, there may be additional PFAS sources nearby. They are planning on further investigation and awaiting results from the second and third rounds of sampling which will guide future responses.

DNR staff also collected fish samples form Lake Monona near Starkweather Creek for PFAS. Once the samples are received, the DNR and DHS will review the results and make any necessary revisions to local fish consumption advisories. The water samples were taken this summer.

The DNR is currently evaluating the need for any additional actions, such as investigating possible sources of contamination, conducting a more comprehensive fish contaminant monitoring project on Lake Monona in 2020, and targeting a variety of species for PFAS and other contaminants.

"The DNR will work with state and local public health officials, the city, the airport and Wisconsin Air National Guard to expand and accelerate the investigation at Truax and Dane County Regional Airport to address public concerns based on the results of this first sampling round," said DNR Environmental Management Division Administrator Darsi Foss. "We will continue to step up our efforts to investigate PFAS contamination in Dane County and across Wisconsin, and work with all our partners to address concerns that may arise."

Samples were analyzed for 36 PFAS compounds, including PFOS and PFOA, at the Wisconsin State Laboratory of Hygiene. Although initial analysis reveals not all the 36 PFAS compounds were detected, some of the compounds were detected at all locations.

The Environmental Protection Agency does not have a federal drinking water standard for these contaminants. Wisconsin, along with other states are working to address the issue.

In Wisconsin, the Wisconsin Department of Health Services (DHS) is recommending a cumulative groundwater enforcement standard of 20 nanograms per liter or parts per trillion for PFOA and PFOS. The recommended standards will be enforceable once the rules are finalized.

DHS recommends people avoid drinking or accidentally swallowing surface water with elevated levels of PFAS, and, to wash their hands after wading or playing in water with elevated levels of PFAS. DHS also advises that pets should be rinsed with clean water to avoid ingesting PFAS that may be on their fur.