Updated: 3:47 p.m. | Posted: 2:19 p.m.
Minnesota health officials are tightening guidelines for private wells and public water systems in Bemidji and in east metro Twin Cities communities to slash levels of two worrisome pollutants found in their drinking water.
Rules released Tuesday by the Minnesota Department of Health call for tightening the acceptable levels of the chemicals PFOA and PFOS. The department made the move after a new state-level analysis examined the potential for mothers to pass along the chemicals to fetuses and nursing infants.
The state decided that in Minnesota, previous advisory levels should be lower, according to health commissioner Ed Ehlinger.
"We err on the side of caution, and that's sort of the tradition we have here in Minnesota to really protect the most vulnerable as best we can," Ehlinger said.
The new state standards are significantly tougher than federal Environmental Protection Agency standards.
The EPA issued guidelines last year for two of the chemicals, known as PFOA and PFOS, at 70 parts per trillion. The new state standards about half the EPA levels.
PFOA and PFOS are among a family of perfluorochemicals, or PFCs, once used by 3M and other companies in stain repellants, non-stick cookware and other products.
Wastes from 3M's PFC manufacturing were sent to Washington County landfills. From there they seeped into the groundwater, the source of drinking water for many east metro communities. In Bemidji, the source of the chemicals was firefighting foam used during training exercises at the airport.
PFCs don't break down in the environment and can travel long distances. They build up in the human body over time. They can be passed onto fetuses through the placenta and to nursing infants through breast milk.
In Minnesota, scientists looked more closely at the potential impact of PFC's on on a fetus or newborn baby.
"Our work focused on really trying to quantify exposures to the developing fetus when the mother is passing on these chemicals through the placenta, as well as the potential for passing them on through breast feeding," said Jim Kelly, program director for the environmental health division of the Department of Health.
State officials say the new guidelines shouldn't deter nursing mothers from breastfeeding. But parents in the affected areas might want to consider using bottled or filtered water to prepare infant formula.
The cities of Cottage Grove, Oakdale, Woodbury, St. Paul Park and Bemidji have public drinking water wells affected by the new standards.
Those cities will be able to take measures to meet the new guidelines, according to Minnesota Pollution Control Agency Commissioner John Linc Stine.
"By conserving water and changing the way they pump their wells," he said, "they should be able to bring their drinking water levels below the level of concern."
Those actions could include shutting off contaminated wells and using cleaner ones. In some cities, restrictions on watering lawns might be needed.
There are also about 120 private wells in the east metro with water that exceeds the new guidelines. Those residents will be provided bottled water and the option of a free filtration system.
Ehlinger cautions that drinking water containing the two chemicals even above the updated standards does not represent an immediate health risk.
"These values are designed to reduce long-term risks and are based on multiple safety factors to protect the most vulnerable citizens, which makes them overprotective for most residents of our state."