Following up on reports of discolored water in a tributary of Cheslea Creek, DNR staff traced milk-colored water to Martin-Brower, a McDonald’s distribution center in Mason City.
Employees at Martin-Brower said they had hosed a spilled milk shake ingredient into a storm water intake Monday morning. After traveling underground through the storm water system, the pollutant surfaced into the tributary on the southwest side of town.
The affected area is a couple of hundred yards long, and lies alongside a popular walking and biking path.
DNR staff took water samples at the site. Field tests showed dissolved oxygen and pH levels were normal, and ammonia levels were low. Based on field results, DNR does not think the water poses an immediate threat to children or pets in contact with the water.
The company must clean up and remove the impacted water from the stream.
DNR sent water samples to a laboratory for additional testing. Staff will monitor the cleanup and consider appropriate enforcement action.