The Mississippi River water samples will be sent to the National Exposure Research Lab in North Carolina for analysis. The EPA facility is one of the few labs in the country that can test for PFCs -- a class of chemicals used in products that resist water, grease and stains. One of the best-known products that used perfluorinated chemicals was Scotchgard, manufactured by 3M.
Very little is known about how most PFCs get into waterways or even the extent of the chemical contamination around the country, said Dr. Andy Lindstrom, the research scientist heading up the agency's testing program. His researchers got a sense of the complexity of the issue last year when they tested a local river for PFCs.
"The study that we did that covered the Cape Fear River showed some pretty interesting results. We had evidence of point sources, numerous point sources throughout the drainage basin. And that was kind of a surprise to us," Lindstrom said.
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The EPA team found higher levels of PFCs than they expected, concentrated in pockets throughout the Cape Fear River. Lindstrom said that probably means there are many different ways that the chemicals are getting to the river.
"If there's any toxicity associated with them at all it's a very good idea for us to come to a good understanding of about where they come from."
"That could be from current manufacturing processes to historical kinds of issues like landfills or wastewater treatment facilities," Lindstrom said. "There's just a lot of different perfluorinated compounds out there that are gonna be coming from a lot of different sources I think."
Lindstrom is anxious to see if the same pattern is true in other waterways. He said the Mississippi River is an excellent test case because it's much larger with a lot more commercial and urban activity.
Minnesota has already tested sections of the Mississippi for PFCs. The Minnesota Pollution Control Agency has found higher levels of the chemicals in the Twin Cities area near former disposal sites and downstream from 3M's Cottage Grove manufacturing plant.
The agency also found a high reading last summer in an area far away from any known PFC manufacturing activity, according to MPCA Administrator Marvin Hora.
"It was a real mystery at Brainerd where you had all these wastewater treatment plants that had actually either none or very low levels in them, and then finding this one real high one. So it was a mystery," Hora said.
The Brainerd investigation revealed that the chemicals were coming from a metal plating business that was legally using a product containing PFCs.
Hora said the business had no idea it was releasing PFCs into wastewater that eventually reached river. When the company was told about the chemicals, Hora says it immediately switched to a different product.
Fish consumption advisories are currently in place downstream from 3M's plant. The advisories are based on fish tissue samples that revealed high levels of the chemicals. Similar actions could occur elsewhere along the river depending on the results from this summer's expanded PFC study. Researchers expect to find high levels of PFCs scattered throughout the Upper Mississippi, Lindstrom said.
PFCs are extremely useful in many products and he doubts industry will find alternatives to them in the near future, he said, even though studies have shown that they are toxic in lab animals and increase in blood concentrations as you move up the food chain.
"If there's any toxicity associated with them at all it's a very good idea for us to come to a good understanding of about where they come from, where they go in the environment and ultimately what we can do to try to mitigate any potential risk that there might be," Lindstrom said.
He hopes to one day test the entire length of the Mississippi for PFCs. Washington state is also interested in working with Lindstrom's lab to test some of its waterways.