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about PFAS contamination.
about water quality PFAS initiatives and study results.
or read about the PFAS Technical Advisory Group.
DNR database
Contact information
For more information about water quality and PFAS, contact:
Adrian Stocks
Water Quality Program

2019 statewide PFAS surface water sampling effort Frequently Asked Questions (FAQ)

In summer 2019, DNR collected water chemistry and fish tissue samples from six waterbodies near known or suspected PFAS contamination sites. Answers to questions being asked of DNR staff are posted on this page, which will be updated regularly. Additional information is available on the main Water quality PFAS initiatives page.

Statewide sampling effort

Why did DNR do this surface water monitoring?

Under the federal Clean Water Act, DNR is required to monitor and assess Wisconsin surface waters and adopt water quality standards to protect, maintain and improve the quality of our nation's surface waters.

How did DNR decide where to collect these samples?

DNR selected waterbodies near known or suspected PFAS contamination, such as: fire suppression training grounds; PFAS detects in drinking water or groundwater monitoring wells, and; sites where elevated levels of PFAS have been detected in wildlife.

Where and when were samples collected?

Sample locations included:

  1. Starkweather Creek (Dane County);
  2. Wisconsin River (Oneida, Lincoln and Wood Counties);
  3. Silver Creek and Suukjak Sep Creek (Monroe County);
  4. Mississippi River (Pierce, Pepin, Buffalo and Vernon Counties);
  5. Menominee River (Marinette County); and
  6. Peshtigo River (Marinette County) and St. Louis River (Douglas County).

Generally, samples were collected from sites upstream and downstream of locations with known or suspected PFAS contamination.

The DNR sampled most of these sites three times during the summer of 2019 (once for the Peshtigo and St. Louis Rivers), with the sampling events at a given site taking place roughly 30 days apart.

Did DNR sample sediment?

No. Sediment sampling is not part of the DNR's annual surface water monitoring strategy.

When will sample results for fish be available?

The DNR expects to receive results by winter 2019-2020, as there is significant processing and analyzing time required for fish tissue samples. The DNR expects to have water chemistry results before any fish tissue results are reported.

The fish analyses for Starkweather Creek are being prioritized by the DNR and the State Laboratory of Hygiene.

What is the difference between nanograms per liter (ng/L) and parts per trillion (ppt)?

These are equivalent units of measurement. 1 nanogram per liter (ng/l) = 1 part per trillion (ppt).

How do the surface water results compare to ambient conditions?

A comprehensive statewide assessment of PFAS in ambient waters has not been conducted in Wisconsin. The sampling design for many of the waterbodies surveyed in 2019 included a sampling location that was upstream of known PFAS sources. These upstream sites are DNR staff's best estimates of ambient PFAS concentrations in the region.

How do the surface water results compare to other sites in Wisconsin?

A comprehensive assessment of PFAS in ambient waters has not been conducted in Wisconsin.

What will DNR do with this information?

The DNR will use this information to evaluate possible sources of PFAS to the waterbodies. This information will also be used to help inform DNR as it begins working with stakeholders to develop PFAS water quality standards.

Starkweather Creek

Does DNR know the source of contamination in Starkweather Creek?

The DNR is evaluating probable sources of contamination in Starkweather Creek. The DNR has concluded that one source is the Dane County Regional Airport – Truax Air National Guard Base. The DNR will be working with partners to assess other potential sources.

What is the extent of the contamination in Starkweather Creek?

PFAS was found in varying concentrations along the entire length of Starkweather Creek (headwaters to mouth).

Who discharges to Starkweather Creek?

The Dane County Regional Airport does have a permitted wastewater discharge to Starkweather Creek. The discharge is primarily stormwater and seasonal treated wastewater from de-icing activities. Other possible sources may include stormwater discharges and groundwater entering the creek. There are historic fire-fighting burn pits where PFAS-containing foam was used. There is also PFAS contamination confirmed at the Truax Air National Guard Base.

Why isn't the DNR sampling sediments in Starkweather Creek?

PFAS distribution in water and sediment is a complex process that is impacted by various factors including, but not limited to: the type of water body, organisms and ecosystem present at the site; the type(s) of PFAS compounds present; time of year and weather (e.g., wet vs. dry seasons); and the type of soils at the site. Research indicates that, in general, the concentration PFAS in the water is higher than what would be found in sediment. Therefore, while no sediment data has been collected at this site, we expect the PFAS levels in the sediment of Starkweather Creek to be much lower than concentrations in water.

Secondly, people can typically be exposed to PFAS in sediment by accidental ingestion through hand-to-mouth activity. The risk of ingesting sediment through recreational activities or handling sediment at the creek is small and is unlikely to cause any illness related to PFAS exposure. Any potential exposure via dermal contact is a minor concern since PFAS does not easily enter the body via absorption through the skin.

Despite this information, the state and local health departments recommend any person wading in the water or touching the sediment at Starkweather Creek wash their hands and avoid any unnecessary contact with sediments or other potential sources of possible PFAS contamination. This would be especially true for younger children due to more frequent hand-to-mouth activity.

Silver Creek

Does DNR know the source of contamination in Silver Creek?

PFAS contamination is suspected from three locations where historic fire suppression training occurred at the U.S. Army-Fort McCoy facility.

What is the extent of the contamination in Silver Creek?

Elevated concentrations of some PFAS were found downstream of the historic fire suppression training area.

Public health and welfare

Is it safe for people to recreate in the water?

We do not expect immediate health risks from recreating in the waters sampled based on detected PFAS levels.

PFAS are not readily absorbed through the skin. However, ingestion of untreated surface water should be minimized or avoided whenever possible. Natural surface waters contain algae, bacteria, viruses and other pathogens that if consumed may pose health risks to humans, pets and other domestic animals.

The Wisconsin Department of Health Services (DHS) recommends people avoid drinking or accidently swallowing surface water and to wash their hands after wading or playing in the water to avoid accidental ingestion of contaminants that may cause illness.

Is it safe to eat fish from the water?

Consumption of fish containing elevated levels of PFAS is a potential human health concern. While DNR did sample fish as part of the study, we do not yet have fish results so we cannot say what concentrations of PFAS are in fish tissue. Special advisories may be issued due to PFAS concentrations in fish tissue after results have been received.

Current fish consumption advisories in place due to mercury and other contaminants should continue to be followed. More information on fish consumption advisories may be found on the Eating your catch - making healthy choices page.

Are there current fish consumption advisories for Lake Monona?

Yes, Lake Monona is included in the statewide fish consumption advisory. This advisory is based on two contaminants - polychlorinated biphenyls (PCBs) and mercury - because these contaminants can build up in your body over time. The risk of health problems increase with the amount of contaminated fish you eat over time.

DNR and DHS will review results from fish tissue sampling once it is received from the State Laboratory of Hygiene to determine if the current advisory is protective for PFAS.

More information on fish consumption advisories may be found on the Eating your catch - making healthy choices page.

Are there any waterbodies that have a fish consumption advisory for PFAS?

Yes, in Pools 3 – 6 of the Mississippi River, consumption advisories for some species are based on levels of PFOS (one of the mostly widely used and studied PFAS) found in fish tissue.

In these locations, the consumption advice that is issued to protect against the risks from consuming PFOS is more stringent than what would be issued based on PCBs or mercury. This means that if you follow fish consumption advisories, you can get the health benefits from eating fish while reducing your risk from contaminants, including PFOS.

More information on fish consumption advisories may be found on the Eating your catch - making healthy choices page.

What advice do you have for pet owners who have pets that come in contact with these surface waters?

Pet owners are encouraged to rinse their pets off after coming in contact with the surface water to avoid pets from accidently swallowing PFAS that may be on their fur.

What do the results mean for fish and wildlife?

Fish health is likely not at risk from exposure to PFAS at these concentrations. Effects on wildlife are unknown and is an active area of research nationally.


What is the difference between standards set for groundwater, public drinking water and surface water?

Each of these standards are developed according to requirements of state and federal laws.

Groundwater standards are set based on the Wisconsin groundwater law, which requires standards to be set to minimize the concentration of a polluting substance in groundwater. These standards are used to monitor groundwater around landfills, to set limits for land application of certain wastewaters and investigation and clean-up from releases (e.g., spills) that cause groundwater contamination.

Public drinking water standards are set based on the federal Safe Drinking Water Act and apply to public drinking water systems (e.g., communities, businesses, etc. providing water to the public) that use either groundwater or surface water. These standards are set to protect the public from both naturally-occurring and human-made contaminants that may be found in public drinking water supplies.

Surface water quality standards are set based on the federal Clean Water Act to protect human health, recreation and aquatic life for our surface waters. These standards are used to determine if a waterbody is "impaired," based on the waterbody's designated use of public drinking water, recreation or to protect fish and aquatic life. These standards are also used to develop restoration plans for impaired waters and to set discharge limits for wastewater facilities.

Public notification

How will DNR notify the public?

The DNR issues news releases, as appropriate. This information is provided to area news outlets. News release specific to the 2019 study were issued on October 7, 2019, and on October 16, 2019.

In addition, DNR maintains this website that contains information about PFAS, which will be updated regularly as new information becomes available.

The state is working with local health departments and any identified responsible parties to post signs to notify the public along Starkweather Creek, at a minimum.

Last revised: Tuesday November 12 2019