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Saint Paul, Minn. – A May 2016 agreement
between the Minnesota Pollution Control Agency 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.
Broadcast version
The Minnesota Pollution Control
Agency and Douglas Corp., a metal plating company in St. Louis Park, have
reached agreement on preventing release of potentially harmful chemicals from
the site that have been getting into fish in Minneapolis’s Lake Calhoun. The chemicals, called PFCs, were found to
have collected on the roof of the facility, where they ran off with rain and
snowmelt to storm sewers feeding into the lake. The Minnesota Department of Health has
issued advisories on eating fish from the lake.
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