East metro residents test higher for PFCs

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Old landfill
The former 3M landfill in Woodbury, where 3M had deposited chemical residue for years. It has been considered a source of PFC groundwater pollution in the east metro area.
MPR Photo/Bill Alkofer

A new study by the Minnesota Department of Health says residents in the east metro have elevated levels of PFCs in their blood.

Two of the chemicals are related to 3M's decades-long industrial operations in the area, including waste deposited at several landfills.

The department sampled the blood of 196 residents whose drinking water had been contaminated, and compared that to the general population.

The levels of three perfluorinated chemicals were present in higher concentrations among east metro residents than in the general population. But the Minnesota Department of Health says there's no evidence the chemicals are making anyone sick.

The Health Department's Jean Johnson supervised the study.

"Even though we can measure these things in the body, particularly with a chemical like this where there's still a lot we don't know, it's very difficult to interpret what these numbers mean in terms of health," said Johnson. "What we can say is that based on the studies we have right now, we're not aware of increased risk of disease based on these low levels."

Two of the chemicals, PFOA and PFOS, are related to 3M's east metro manufacturing operations. The company made Scotchgard, firefighting foam and other products at its plant in Cottage Grove, and deposited waste from those operations at several landfills.

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Tests by the state have shown that the landfills are leaking those chemicals into private and public wells, contaminating the drinking water of tens of thousands of residents.

Both have been shown to cause cancer in lab animals. 3M stopped using the compounds in 2002, after they turned up in the blood of its plant workers.

Johnson says even those workers, with far higher concentrations in their blood, have shown no health problems.

"But I know that it is still disconcerting to know that these chemicals are in the body," Johnson said.

PFOA showed up in tested residents at about four times the rate as it appears in the general population -- about 15 parts per billion, compared to four parts per billion in the general population.

For PFOS, tested residents had about one and a half times as much as the U.S. population -- 36 parts per billion compared to 21 parts per billion the general population.

"I know that it is disconcerting to know that these chemicals are in the body."

The source of another chemical, PFHxS, is not known. It appeared at four times the national rate.

3M spokesman Bill Nelson says the study represents a snapshot in time.

"Going forward, we would expect the PFC serum levels in the participants to go down because of what we know about the chemistry, and that exposure has been taken care of by 3M and the state of Minnesota," Nelson said.

Nelson says it's not even certain that the chemicals come from the 3M operations. He says they could have come from consumer products.

The Health Department also expects the levels to come down. Many people have installed water filters and 3M has paid for some of the filtration.

The study of east metro residents was ordered by the Legislature. State Sen. Katie Sieben, DFL- Cottage Grove, sponsored the bill requiring the study.

"As a mother of a young child and as a senator who represents thousands of families, I don't want these chemicals in our drinking water," Sieben said. "And the fact that now, this study is confirming that people's exposure is higher than others in the country, even without knowing conclusively how much, it's not good news for us."

Sieben says she wants further study of the data. But because the chemicals are so new, it's hard to find experts.

Matt Simcik teaches environmental and occupational health at the University of Minnesota and has studied PFCs. He says we don't know at what point the chemicals might become dangerous to humans. But he's concerned that no children were included in the study.

"We do know that these chemicals do play games with lipids in the blood and liver, and lipids, fats, are very important in fetal development," said Simcik.

Simcik says the Health Department should follow up the blood study with an investigation of whether the higher levels are causing health problems among this group of people.

One comparison the department plans to make is between blood levels and well-water contamination -- to see if those with the highest levels in their water also had the highest levels in their blood.

The department will present its results at public meetings in two weeks. People who participated in the study got their results over the last few months.