Since PFAS investigation and mitigation activities in the east Twin Cities area began in 2002, over 150 square miles of groundwater contamination affecting the drinking water supplies of over 140,000 Minnesotans have been identified.
In response, Minnesota Department of Public Health (MDH) and Pollution Control Agency (MPCA) have sampled over 2,800 private wells and issued drinking water advisories for nearly 1,050 where PFAS was detected in levels exceeding statewide health-based criteria. Homes that rely on these wells are routinely either connected to municipal water systems or provided with granular activated carbon filters that are maintained by the state. An interactive map that contains information about sources of PFAS contamination, sampling results, and priority sampling area boundaries is maintained online by MPCA. MDH also invested in a bio-monitoring study of residents within priority sampling areas to gain additional insight into the efficacy of mitigating actions. Three rounds of sampling completed between 2008 and 2016 showed that PFAS levels in the bodies of participants were higher than average for the general U.S. population, but also demonstrated significant and steady reductions in blood serum levels following the installation of treatment systems.