State and federal regulators announced a $3 million package Friday morning to begin cleaning up a contaminated portion of the St. Louis River in northeastern Minnesota, a vital but threatened estuary for Lake Superior and the Great Lakes.

The grant was announced by the U.S. Environmental Protection Agency (EPA) and the Minnesota Pollution Control Agency (PCA) on the shores of the river's estuary.

The EPA will provide $2.19 million from its Great Lakes Restoration Initiative, while Minnesota will contribute $1.1 million through the state's Clean Water Fund.

The stretch of river — the largest freshwater estuary in the United States and an important fish spawning ground for Lake Superior — was designated an "area of concern" in 1987, marking it as one of the most polluted areas around the Great Lakes in the eyes of international water quality regulators. Decades of industrial use left it contaminated with sewage, pollution and timber byproducts.

The money will be used to fund a study of cleanup options at three sites, engineering plans for the restoration of seven sites, evaluation of the potential to use dredged river sediment in local habitat restoration, and ecosystem monitoring.

"The EPA and the MPCA are working together to reverse over 100 years of environmental degradation in the St. Louis River Area of Concern," EPA Regional Administrator Susan Hedman said in a statement issued before the announcement Friday morning.

Over the past three years, the Great Lakes Restoration Initiative has provided more than $320 million to clean up toxic contamination in the Great Lakes region.

On the St. Louis River, projects have included creating riffles to improve spawning areas for sturgeon below the Fond du Lac Dam and removing sawmill waste in an area called Radio Tower Bay.