KENT, Wash. -- Tim Davis was biking along the Green River trail when his scenic ride took a nasty turn.

"Started looking down the river and the first thing I see are shopping carts," he said. "You got wheels, you got metal stuff in the mud, you got one, two, three...seven shopping carts!"

Davis saw a scattered pile of shopping cars, bicycles and smaller items like CDs covering the riverbed.

What Davis didn't know at the time is that all of that has always been there. But none of it was visible until Army Corp of Engineers lowered the river's water levels in order to repair the levees.

Whatever the case, Davis wants the dumping stopped and the mess cleaned up.

"An investigation needs to be put into place to find out who's dumping here," he said.

KOMO News investigated, and found everybody pointing fingers. The King County Department of Natural Resources said the trash is not its problem and that Kent is responsible. But the city insisted the cleanup is up to the county.

Davis fears there are pollutants and toxins that may be floating down river. But nobody knows whether there are any toxins because nobody is looking into the mess.