Officials with the Fridley Fire Department spotted a large and glossy sheen traveling downstream on the Mississippi River by the Minnesota 610 bridge in Coon Rapids early Tuesday afternoon and used booms to divert the sheen away from city water intakes in Minneapolis and St. Paul.
The next morning, at about 8:10 a.m. Wednesday, a smaller sheen was reported near the west shore of the river by West Coon Rapids Dam Regional Park. State agencies are investigating whether the second sheen is connected to the initial incident, according to the Minnesota Pollution Control Agency.
All of the samples tested by the Minnesota Department of Health lab came back negative “for substances which would pose a threat to the safety of municipal drinking water systems,” said the MPCA on Thursday. State agencies are still conducting testing and trying to determine the source of the water discoloration, but no additional sheens were spotted Thursday.
Still, the back-to-back sightings drew precautionary action this week from St. Paul Regional Water Services, which has shut down an intake pumping station in Fridley to keep the flow from entering the chain of lakes, where drinking water cycles before it reaches a treatment plant.
No immediate threat
A sheen can be bacterial — such as decaying plants — or petroleum in nature, according to the Minnesota Pollution Control Agency. The nature of the sheens remains unclear, the MPCA said.
“There is no immediate threat to the SPRWS drinking water supply at this time,” the SPRWS said in a statement. “SPRWS has the ability to use water from lakes and wells, which is what we are doing at this point. The water in the supply system being routed to the treatment plant is safe to use and has not affected the quality of the drinking water being provided to customers.”
The intake station in Fridley remains offline while SPRWS works with the Department of Health and other state agencies to conduct additional water quality testing.
Check for updates at tinyurl.com/FridleySheen2024.
Sheens
Minnesota Pollution Control notes in its advisories that it routinely receives calls from concerned citizens “who have discovered apparent color sheens on water in ditches, ponds, wetlands, lakes and other areas with stagnant, standing water.”
“Often these sheens have an iridescent or rainbow‐like appearance similar to what one sees when a small amount of oil, gasoline or other petroleum product is spilled on water,” reads the MPCA materials. If there is no obvious source of spilled petroleum, the sheen could be an organic, or humic, sheen caused by bacteria from decaying plant matter.
St. Paul Regional Water, a public utility, serves approximately 450,000 customers in the Twin Cities, treating and pumping an average of 40 million gallons of water per day to St. Paul, Maplewood and a dozen other east metro communities.
