A new permit for discharging water from the company's Cottage Grove plant has some tighter requirements on cleaning up PFCs.
In at least one aspect of cleaning up perfluorochemicals, or PFCs, in the east metro, the state of Minnesota and 3M Co. are in agreement.
The company's five-year wastewater treatment permit at its plant in Cottage Grove is up for renewal, and proposed changes target a particularly harmful kind of PFC to keep it from further impairing the Mississippi River, where 3M dumps its treated water.
The chemical, perfluorooctane sulfonate, or PFOS, was a key ingredient in Scotchgard products before the company voluntarily phased out its production. Groundwater and soil around the Cottage Grove plant, however, are still contaminated. And data from the Minnesota Pollution Control Agency show PFOS is still making its way to the river.
Two weeks ago, Minnesota Attorney General Lori Swanson filed suit against 3M, demanding that it pay the cleanup costs for decades of pollution caused by chemicals that have leached into the Mississippi River and the drinking water of communities across the east metro area. The suit followed a breakdown in out-of-court negotiations with the state.
But on the Cottage Grove plant's wastewater permit, and its new requirements, there was no such contention.
"The draft permit was and is the result of a cooperative effort between 3M and the MPCA," said Bill Nelson, environmental communications manager for the company. "But that being said, the public is still being invited to offer their input on it."
A 30-day comment period began Jan. 3. A public information meeting is planned in Cottage Grove on Jan. 26.
The stretch of the Mississippi River below the 3M plant is listed as "impaired" under the federal Clean Water Act due to the presence of PFOS in the tissues of fish taken from that part of the river.
Unlike pesticides and other chemicals that build up in the fatty tissue of fish, which anglers can cut away during fish cleaning, PFOS binds to proteins. Such high levels of PFOS prompted the Minnesota Department of Health to release drinking water and fish consumption advisories.
When the National Park Service began testing bald eagle nestlings for PFOS in 2006, they were found to have the highest levels reported anywhere in the world, though numbers have since improved.
Ralph Pribble, spokesman for the MPCA, said that, for the first time, 3M will be required to meet new, lower emission standards for PFOS.
That plant is one of four sites in the east metro area -- the others are in Woodbury, Oakdale and Lake Elmo -- that have been contaminated by PFCs, chemicals that do not occur in nature but which accumulate in fish and other wildlife. In animal studies they have been linked to cancer and developmental problems. Research into their health impact in humans is ongoing.
The company must meet the new standard in phases, and must also devise a way to take the PFC out of the water. Pribble said that the contaminant has only been of concern since 2005, and the technology to address it still is being developed.
According to MPCA documents, the Cottage Grove plant must meet the water quality standards to limit PFOS "as soon as possible."
"They have to meet discharge limits eventually," he said. "But not immediately. It's such a new technology no one is sure how to do it."
The heart of that technology is a requirement that 3M install a granular activated-carbon treatment system to clean the water before it's dumped into the river, MPCA documents say. Aside from PFOS, the documents say, the system also has been proven effective in reducing mercury pollution.
The permit outlines strict procedures for monitoring, testing and reporting how well the system is doing its intended job.
Staff writer Josephine Marcotty contributed to this report. Jim Anderson • 651-735-0999