St. Croix pollution built up over decades

Phosphorous contamination of the southern part of the river began years ago, and some officials say it shouldn't delay new bridge.

By Kevin Giles, Star Tribune

Last update: September 17, 2007 – 9:31 PM

Phosphorous contamination that landed the federally protected St. Croix River on Minnesota's impaired-waters list for the first time has been building for decades, several experts familiar with the river said Monday.

One of them, Craig Affeldt of the Minnesota Pollution Control Agency, said that large algae blooms in Lake St. Croix -- the portion of the St. Croix River between Stillwater and Prescott, Wis. -- have resulted from excessive phosphorus, which can alter a river's ecosystem.

"Whether that's runoff from streets, parking lots, livestock or fertilizers, this is what people introduce to the landscape because that's how we live," said Affeldt, a specialist on St. Croix basin matters.

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