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Tests show PFOS levels are declining in Mississippi

Levels of a 3M chemical found in Mississippi River fish below the Twin Cities are declining but remain high between the 3M manufacturing plant in Cottage Grove and the dam at Hastings.

The Minnesota Pollution Control Agency recently reported these findings after extensive sampling over the past year of the water and aquatic life from Pool 2, a 32-mile length of the Mississippi between the Ford Dam and Hastings, for perfluorooctane sulfate, or PFOS.

The MPCA has been sampling fish in the river as part of follow-up studies of the environmental impacts of perfluorinated chemicals, a class of chemicals that do not break down in the environment and accumulate in animals and people.

3M began manufacturing the chemicals at the company's Cottage Grove facility in the 1940s, disposing of wastes at several east metro area locations. The chemicals have contaminated groundwater and fish in area lakes and the river.

3M announced a phase-out of PFOS and PFOA production in the early 2000s. The MPCA has listed this portion of the river impaired for PFOS since 2008.