Oakdale city well to be filtered

With a filtration system donated and installed by 3M, Oakdale hopes to reduce the level of perfluorochemicals (PFCs) in one of its six contaminated municipal wells.

An agreement approved by the Oakdale City Council Aug. 9 says 3M will install a granular activated-carbon water treatment system for municipal well No. 5.

Mayor Carmen Sarrack characterized the action as a precaution, saying that the levels of perfluorooctanic acid (PFOA) and perfluorooctane sulfonate (PFOS) - the two chemicals identified in six of the city’s wells - are already low enough so the water is safe to drink.

“We are below the safety levels, so this is a proactive measure,” Sarrack said at an Aug. 10 press conference. “We feel we can lower that level even more.”

The move may be the first step toward completely eliminating the contaminants from the city’s water, said Jim Kelly, a health risk assessor for the Minnesota Department of Health.

“The hope is, and the tests really suggest that (the filtration system) would be 100 percent effective,” Kelly said. “That’s the goal, certainly.”

The filtration system is similar to those used successfully on 12 contaminated private wells in Lake Elmo. Kelly said the filters there have filtered out the chemicals entirely. But there is still some uncertainty, because this process has never been tried before with large-volume municipal wells, he added.

As part of the agreement, 3M will consider providing filtration systems for the other wells if the initial system functions effectively.

Once the filtration system on well No. 5 is installed, the city of Oakdale will operate and maintain it, but 3M will cover all costs for at least five years.

If the level of contamination in the water stays below state standards for each quarter of the final two years of the five-year period, the city will take responsibility for all maintenance and operation costs.

Mixed response

Council member Stan Karwoski, who called the agreement a “win-win situation”, said the operation and maintenance costs would be “very manageable.”

Other members of the city council and staff echoed Karwoski in their support for the agreement.

“I’m very pleased with the agreement,” City Administrator Craig Waldron said. “I think it’s well done, it protects the city, and it really goes the extra mile to ensure the citizens that they have a high quality water source.”

Not everyone was satisfied, however, including Stephen Randall, an attorney representing Washington County residents in a lawsuit against 3M over the potential effects of PFCs in the bloodstream.

“We just want you to know that we do not think this one single step will solve the problem,” Randall said at the Aug. 9 council meeting.

Waldron said the agreement is not a response to the lawsuit.

According to 3M spokesperson Bill Nelson, the company is simply ensuring that the water remains consistently and reliably below state guidelines.

“It was basically 3M that took the initiative and approached the city about installing a system at well No. 5,” Nelson said.

Where it began

The agreement comes a year after tests revealed trace amounts of PFCs in private wells near the Washington County Landfill in Lake Elmo and in the Abresch site near Granada Avenue and Highway 5 in Oakdale. The two locations were used years ago as disposal sites for waste from 3M’s Cottage Grove facility, where the company produced the potentially harmful PFCs from the late 1940s until 2002. The synthetic chemicals were used to make various 3M products such as Scotchgard and Teflon.

“We strongly think it comes from one of the disposal sites,” Kelly said. “We don’t know which.”

The Minnesota Pollution Control Agency is investigating the source of the contamination, Kelly said.

In follow-up testing conducted last December, five of Oakdale’s eight municipal wells were found to have less than one part per billion of PFOA and PFOS. A sixth well tested positive in later tests.

The state standards - the “health-based values” set by the state health department - are one part per billion for PFOS and seven parts per billion for PFOA. Currently there are no federal guidelines for either substance.

Since the PFC family of chemicals is relatively new and knowledge of them is even more recent, the long-term effects in people are unknown. High concentrations have been shown to cause liver damage and increase the risk of cancer in animals.

“We have no evidence that there are these kinds of effects in humans,” Kelly said. The EPA is currently studying the effects of the chemicals, but have come to no conclusions, he added.

The worst well

After the contamination was discovered in the city wells, the state health department began testing them on a monthly basis. In July, well No. 5 reached PFOS levels above the acceptable standard for the first time, at just over one part per billion, Kelly said.

The well, located at Walton Park, has been switched so it does not provide water to the general water supply as often. Since Oakdale’s wells are inter-connected and the other wells have much lower contamination levels, the overall concentrations of PFCs in the drinking water are not as high. The inter-connected system also means, though, that the chemicals are present throughout the city’s water supply although the nearest well might not be contaminated.

The filtration system will use activated carbon, or charcoal, to adsorb the chemicals from the water, Kelly said. The activated carbon, a powdered, granular substance generated from burnt corn cobs or coconut shells, has a large surface area that the chemicals attach to as they pass through the filter.

Nelson said it is too early to tell how long the project might take or how much it will cost. City Engineer Brian Bachmeier estimated that it would take about a year and will cost more than $1 million.

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