Beneath the Surface: Exploring PFAS and Drinking Water on French Island, Wisconsin
The growing concern of finding per- and polyfluoroalkyl substances (PFAS) in drinking water has led USGS scientists to conduct more comprehensive analyses that encompass an extensive list of compounds that can be found in drinking water. These analyses will develop a more complete drinking water contaminant list that managers can use to make more informed public health decisions.
Secure drinking water is important for everyone. It is crucial for preventing dehydration, maintaining physical performance, and reducing the risk of waterborne diseases. While public awareness concerning PFAS is increasing, many individuals remain unaware of what PFAS are, their potential health risks, and their presence in everyday products and the environment. In addition, although public drinking water supplies are often tested for PFAS, there are many contaminants of concern for human health that could make their way into drinking water.
The town of Campbell, Wisconsin, is located on French Island, an alluvial island in the Mississippi River. In 2020, PFAS compounds were found at the La Crosse Airport (located on French Island), triggering an island-wide drinking water advisory and further testing by the Wisconsin Department of Natural Resources. PFAS contamination was found to be widespread and alternative drinking water sources were assessed for affected residents.
In 2021, USGS scientists conducted a more comprehensive contaminant characterization on drinking water supplies from 11 residential and community locations to assess 1) tapwater risks beyond recognized PFAS issues, 2) day-to-day and year-to-year risk variability, and 3) the ability of the underlying sandstone groundwater system (aquifer) to serve as a backup source of water to help reduce exposure to PFAS in drinking water. To answer these questions, the scientists analyzed 510 organics, 34 inorganics, and 3 microbial groups that included cyanotoxin, disinfection byproducts, pesticide, PFAS, pharmaceutical and semi volatile/volatile organic chemicals. These analytes were further evaluated to determine potential human-health risks to individuals from tapwater exposures.
Of the analytes tested, 76 organics and 25 inorganics were detected at least once in French Island tapwater samples across all sites. Tapwater inorganic compounds of potential human-health concern were within drinking water standards for public supply and included uranium, lead, nitrate-nitrogen, manganese and fluoride. Although both uranium and lead had concentrations well-below enforceable standards, no amount of these contaminants is considered safe for vulnerable individuals, including infants and children.
Scientists found simultaneous exposures to multiple contaminants with potential human health concern in the alluvial-aquifer sourced tapwater on French Island, but exposures to PFAS compounds were the primary drivers of human-health risks in samples collected adjacent to the airport. However, inorganic and volatile organic chemical exposures of human-health concern were also found in several tapwater samples without detectable PFAS. Because no contaminant risk was observed in samples sourced from the underlying sandstone aquifer, this deeper groundwater system was considered an alternative drinking water source to mitigate alluvial-aquifer tapwater PFAS exposures to French Island residents.
This study was supported by the USGS Ecosystems Mission Area, Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology Programs).
The growing concern of finding per- and polyfluoroalkyl substances (PFAS) in drinking water has led USGS scientists to conduct more comprehensive analyses that encompass an extensive list of compounds that can be found in drinking water. These analyses will develop a more complete drinking water contaminant list that managers can use to make more informed public health decisions.
Secure drinking water is important for everyone. It is crucial for preventing dehydration, maintaining physical performance, and reducing the risk of waterborne diseases. While public awareness concerning PFAS is increasing, many individuals remain unaware of what PFAS are, their potential health risks, and their presence in everyday products and the environment. In addition, although public drinking water supplies are often tested for PFAS, there are many contaminants of concern for human health that could make their way into drinking water.
The town of Campbell, Wisconsin, is located on French Island, an alluvial island in the Mississippi River. In 2020, PFAS compounds were found at the La Crosse Airport (located on French Island), triggering an island-wide drinking water advisory and further testing by the Wisconsin Department of Natural Resources. PFAS contamination was found to be widespread and alternative drinking water sources were assessed for affected residents.
In 2021, USGS scientists conducted a more comprehensive contaminant characterization on drinking water supplies from 11 residential and community locations to assess 1) tapwater risks beyond recognized PFAS issues, 2) day-to-day and year-to-year risk variability, and 3) the ability of the underlying sandstone groundwater system (aquifer) to serve as a backup source of water to help reduce exposure to PFAS in drinking water. To answer these questions, the scientists analyzed 510 organics, 34 inorganics, and 3 microbial groups that included cyanotoxin, disinfection byproducts, pesticide, PFAS, pharmaceutical and semi volatile/volatile organic chemicals. These analytes were further evaluated to determine potential human-health risks to individuals from tapwater exposures.
Of the analytes tested, 76 organics and 25 inorganics were detected at least once in French Island tapwater samples across all sites. Tapwater inorganic compounds of potential human-health concern were within drinking water standards for public supply and included uranium, lead, nitrate-nitrogen, manganese and fluoride. Although both uranium and lead had concentrations well-below enforceable standards, no amount of these contaminants is considered safe for vulnerable individuals, including infants and children.
Scientists found simultaneous exposures to multiple contaminants with potential human health concern in the alluvial-aquifer sourced tapwater on French Island, but exposures to PFAS compounds were the primary drivers of human-health risks in samples collected adjacent to the airport. However, inorganic and volatile organic chemical exposures of human-health concern were also found in several tapwater samples without detectable PFAS. Because no contaminant risk was observed in samples sourced from the underlying sandstone aquifer, this deeper groundwater system was considered an alternative drinking water source to mitigate alluvial-aquifer tapwater PFAS exposures to French Island residents.
This study was supported by the USGS Ecosystems Mission Area, Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology Programs).