Well water health risks prompt state action

Groundwater contamination map
This map shows where the MPCA is cleaning up drinking water on the east side of the Twin Cities.
Courtesy MPCA

A contaminant found in well water in three east metro communities could be a bigger health risk than previously thought, leading state officials to install more filters to protect residents' drinking water.

The Minnesota Department of Health has revised its health-based guidance for trichloroethylene, or TCE.

Private wells in Bayport, Baytown Township and West Lakeland Township had already been retrofitted with special filters if TCE levels were 5 micrograms per liter or above.

That level was associated with cancer risks, but more recent research has shown TCE could present health risks to the immune system, said Kate Sande, a health department toxicologist. The new health department guidelines recommend exposure levels below 0.4 micrograms per liter.

"The science has been evolving. Scientists have been studying the health effects and the toxicity [of TCE]," Sande said. "Non-cancer health effects for TCE are more of a concern than we previously thought."

TCE was first detected in the groundwater in 1987, and the area was declared a state and federal Superfund site. Officials believe the source of TCE, a volatile organic compound used as a metals degreaser, was likely a shop in Lake Elmo that's no longer there.

It's still unclear what specific immune health problems could be linked to TCE, but animal studies signal that even lower exposure levels present a risk, Sande said.

Health officials are most concerned about infants and children, because their immune systems are still developing. Pregnant women and people with weak immune systems could also be at greater risk. Sande said exposure could come through both drinking water with TCE or by breathing the air, so health officials recommend taking steps such as opening windows to improve ventilation when boiling water or taking a shower.

NEW FILTERS, TESTING

Although TCE has been detected in some 400 private wells, the new health guidelines only affect about 115 wells in Baytown Township, Bayport and Lakeland Township. The Minnesota Pollution Control Agency expects to install about 115 granular activated carbon filters on wells by September, said project leader Kevin Mustonen.

At least 16 well owners already had installed the filters voluntarily even though their TCE levels were below the previous 5 microgram threshold, he said. Besides installing more filters, the MPCA will also increase monitoring for TCE, Mustonen said. Many wells were only being monitored once every four years because concentrations of TCE were previously low enough. Those wells will now be tested two or three times a year.

Three public meetings are scheduled in June and July to educate residents about the new health guidance for TCE. The first meeting takes place Monday in Baytown Township.

Kent Grandlienard, chairman of Baytown Township Board, said he expects the new health department guidance won't come as much of a surprise to residents. TCE in groundwater has been a known problem in the area for years now, he said.

One of the biggest concerns previously has been whether the contamination would impact real estate values, he said, but there's been little evidence of that. The filters are 100 percent effective in removing the TCE.

Still, Grandlienard said he knows some people in the community will be concerned that TCE could come with additional health risks. "It's your drinking water," he said.

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