The Big Story Blog

Environmental quality, chemicals and the discharge rules

Posted at 12:58 PM on October 13, 2011 by Paul Tosto
Filed under: Environment

Why now?

It's one of the questions I asked this morning as I read and posted on our MPR News report about the Metropolitan Council weighing legal action against 3M over discharges into the Mississippi River.

It's been an ongoing issue for years among the 3M facilities in the east metro. The company signed a consent order in 2007 with the Minnesota Pollution Control Agency detailing the clean-up.

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The issue's resurfaced because two 3M plant permits -- the metro plant near downtown St. Paul and the Eagles Point plant near Cottage Grove -- are up for renewal.

"There is no current limit in the wastewater plants' permits for PFCs (Perfluorochemicals) ," says MPR News reporter Stephanie Hemphill.

The only place such limits have been imposed is on the Brainerd wastewater treatment plant; a metal-plating company in town was thought to be responsible for high levels of PFCs in that wastewater. The company has since switched to using a different product.

It is only a federal mandate in the sense that the federal Clean Water Act requires states to make plans to clean up "impaired waters," and that section of the Mississippi River is defined as impaired because of the PFC buildup in fish tissue.

The Minnesota Pollution Control Agency is choosing this moment to impose a limit because the two plants' permits are up for renewal. MPCA and Met Council have been discussing this since early in 2011.

The limit the MPCA wants to impose is 10 nanograms per liter, which is the same as 10 parts per trillion, Hemphill adds. The current Health Risk Limit for drinking water is .3 micrograms per liter, which is the same as .3 parts per billion.

So why does the MPCA want a lower limit than it requires now for drinking water? Hemphill tapped MPCA's Katrinia Kessler for an answer:

"It all comes down to the fact that we have to protect to a level that won't cause risk in humans that consume the fish," Kessler says. "And epidemiology shows that bio-accumulation happens in fish and then in people that consume the fish in such a way that we need to have the effluent be at no greater than what we are proposing for the Met Council."


About Paul Tosto

Paul Tosto

Paul Tosto writes the Big Story Blog for MPR News. He joined the newsroom in 2008 after more than 20 years reporting on education, politics and the economy for news wires and newspapers across the country.