The towns of Marshfield and Adams join a growing list of communities that have closed municipal wells because of the respective levels of PFAS in their drinking water.
Two central Wisconsin cities are among three public water supplies that have detected so-called “forever chemicals” at rates recently related to state health officials.
The Wisconsin Department of Natural Resources said Thursday that sampling found three systems exceeded the state’s health hazard index, or groundwater standard, of 20 parts per trillion recommended by the Wisconsin Department of Health Services.
DNR declined to name the third system on Thursday until customers were informed about the results of samples it received this week.
Adams obtained its results on May 4 and shut down one of its two wells whose levels were above the hazard index, which measures health risks related to mixing PFAS chemicals in water. Marshfield closed four of the 15 wells after the results were announced on Tuesday.
“For Marshfield, their level was 24 parts per trillion,” said Steve Elmore, director of the DNR’s Bureau of Drinking Water and Groundwater.
On Thursday, Marshfield Utilities stressed that the risk to public health remains low. The city utility said people and businesses can continue to use municipal water.
“Marshfield Utilities is not violating any drinking water standards or regulations and has taken consistent action to protect the health of its customers,” the city utility said in a release announcing the findings.
The city plans to investigate treatments to remove PFAS from its drinking water or drill New wells to maintain service. Marshfield serves more than 18,000 customers while Adams provides drinking water to about 2,600 people in the city and nearby Friendship Village.
PFAS, or perfluoroalkyl and polyfluoroalkyl substances, represent thousands of synthetic chemicals found in everyday products such as fire extinguishing foams and stain-resistant clothing and cookware. They have been linked to serious health problems including kidney and testicular cancer, and the chemicals do not break down easily in the environment.
During its Drinking Water and Groundwater Study Group meeting on Thursday, the DNR said that 126 municipal systems have expressed interest in testing PFAS. Out of them, the agency has obtained the results of 36 water supply out of 49 that have been sampled. Chemicals were detected in 11 systems while no trace of PFAS was detected in 25 systems. Of those 11 systems, only three — Marshfield, Adams and Unknown Community — had levels of concern.
“We are working personally with the systems that have been affected, and (we) are working with those systems on follow-up actions and communications plans,” said Kyle Burton, DNR’s Director of Field Operations.
The number of systems tested for PFAS so far is a small fraction of Wisconsin’s more than 11,000 public water supplies.
Elmore said the DNR plans to continue to use the health officials’ recommended groundwater standard to inform the public of any health risks. However, the agency acknowledged that the system may not be needed to limit exposure to levels below the proposed drinking water standard of 70 parts per trillion approved by the Wisconsin Natural Resources Board in February.
Asked about adjusting its recommendations during a meeting on Thursday, Sarah Yang, a DHS groundwater toxicologist, said state health officials do not plan to change it.
“Those are the levels we believe in the state, above which, there could be a health hazard to people,” Yang said.
The agency will continue sampling under the project through September, and municipal drinking water systems interested in testing can still participate by emailing the DNR.
Ground water sampling for PFAS to start soon
DNR also shared Thursday that it is partnering with the Wisconsin-Stevens Point Center for Watershed Science on a new project to sample groundwater for chemicals.
“We’re looking to sample 450 private wells evenly distributed across the state to get more information,” Burton said.
“Two-thirds of the population in Wisconsin receives drinking water from groundwater, and there are many areas of the state where we do not know the levels of PFAS in groundwater,” Elmore said. “The groundwater project is really focused on achieving statewide distribution. We are trying to get a sample in every township across the state.”
Elmore said they are focusing on wells that draw from shallow groundwater. The agency hopes to determine where PFAS are coming from and whether consumer products can play a role in people’s homes. The DNR expects to finish sampling and analysis by the end of September.
Status of new drinking water standards for PFAS
In February, the Wisconsin Natural Resources Board failed to set groundwater standards for the chemicals. Nevertheless, it approved surface water and drinking water standards for the two most common PFAS chemicals: PFOA and PFOS. The drinking water threshold reflects the EPA’s health advisory level of 70 parts per trillion for the chemicals.
“Those clarification discussions will relate to confirming that the two clearinghouse rules comply with the provisions of the Administrative Rules of Wisconsin Law (Chapter 227 of the Wisconsin Statutes) and other authorized statutes,” Mickelson wrote.
If the Legislature approves the rules, the new standards could be published in July. That means the largest public water supplies in Wisconsin may require PFAS sampling as early as November.