Levels are declining of a suspected carcinogenic chemical found in fish in the Mississippi River, show data from the Minnesota Pollution Control Agency.
A recent river sampling over the past year of the water and aquatic life from a 32-mile stretch of the river between the Ford Dam and Hastings, Minn., shows the presence of a chemical known as PFOS is generally falling. However, the survey found fish in the area still show higher levels of the chemical.
PFOS was used in manufacturing at 3M's Cottage Grove plant. The highest levels of P F O S are found downstream from the plant, according to the study. 3M phased out production of the chemical In the early 2000s,
Overall, the study's finding is good news for the river, although the contamination is still a problem for fish, said the MPCA's Katrina Kessler.
"It also means that we still have work to do at the lowest part of the pool and that we need to think more about how we can protect fish and wildlife and humans that eat the fish at that lowest part of the pool," Kessler said.
"PFOS accumulates in the livers of fish and we know that it bioaccumulates up the food chain," Kessler said. "So if a fish is consumed by a larger mammal, including humans, that PFOS ends up at higher concentrations of th blood stream of the organism that consumed the fish"