The U.S. Coast Guard Marine Safety Detachment Quad Cities is investigating yet another mystery sheen on the river today.
The sheen, which appears to be some kind of petroleum product, was spotted near the Rock Island Arsenal hydroelectric dam Friday morning.
Crews are now headed up river to see if they can find the source of the slick.
This is the fourth such oil slick seen on the Mississippi this spring.
The Illinois DNR tells Local 4 News that often residents will dump oil products down sewer drains after changing their car's oil, then spring rains push those products out into the river.
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