MPCA announces resolution of investigation in PFOS in Lake Calhoun

Contact: Ralph Pribble, 651-757-2657

Saint Paul, Minn. — A May 2016 agreement between the Minnesota Pollution Control Agency (MPCA) and a metal plating facility in St. Louis Park, Minn. resolves an effort to find the source of PFOS (perfluorooctane sulfonate) contamination in fish and water in Lake Calhoun, and addresses continued releases of both PFOS and chromium to the environment.

PFOS was first detected in water in Lake Calhoun by researchers at the University of Minnesota in 2004. Following this discovery, MPCA researchers tested fish from the lake for PFOS and found high concentrations in fish tissue. The Minnesota Department of Health (MDH) issued a fish consumption advisory for PFOS in Lake Calhoun, and the MPCA listed the lake as impaired under the federal Clean Water Act.

MPCA tested numerous stormwater samples for PFOS in an attempt to find the source of PFOS to the lake. The testing eventually led to the discovery that Douglas Corporation, a metal plating facility in St. Louis Park, was the source of PFOS in stormwater going to Lake Calhoun. PFOS was used by the company in part of their manufacturing process. When fumes were vented to the roof both PFOS and chromium accumulated to high levels on the roof itself, which eventually contaminated stormwater during rain and snowmelt.  The company stopped using the PFOS-containing product in 2010.

Douglas Corporation has taken a number of other actions to try to address the discharge of PFOS from its facility, including closing roof vents, replacing the roof, and replacing plating and etch baths. While levels of PFOS in stormwater leaving the facility have decreased following these actions, there’s still PFOS in the stormwater discharge.  The agreement between Douglas Corporation and the MPCA includes requirements to address the discharge.

Monitoring by both the company and MPCA has been ongoing since discovery of the problem. Shallow groundwater at the facility and off-site is contaminated with PFOS and chromium at levels that exceed MDH’s health risk limits for drinking water.  However, PFOS has not been detected in nearby municipal drinking-water supply wells.

Under a Schedule of Compliance agreement which Douglas and the MPCA signed in May 2016, the company will continue monitoring stormwater leaving its facility and is required to either design a system that will capture stormwater before it can leave the facility or treat PFOS in stormwater to a level that is below the current MPCA limit for Lake Calhoun. The company is also required to continue investigating the extent of groundwater contamination and to commence cleanup actions if the MPCA determines cleanup is necessary. The agreement is legally binding and contains penalties if the company does not comply with it.

Efforts by the company to address their use of PFOS appear to be having a positive effect on levels found in fish in the lake. The last testing in 2013 showed PFOS concentrations in fish were decreasing. The MPCA intends to test again in 2016.

PFCs are used worldwide in industrial applications and are valued for their durability and other special properties. But those same properties make them extremely persistent and mobile in the environment, and they can be found today all around the globe. Douglas Corporation purchased their product from a company based in Germany.