What about the deep deposits of toxic industrial sediment behind the Sixth Street dam?  By

What about the deep deposits of toxic industrial sediment behind the Sixth Street dam?

In 2011, GRWW & the Grand Valley Metro Council received an EPA grant to conduct sediment testing in the area between the Sixth Street Dam and Ann Street. Limited sediment was found. The sediment that was found was tested and found to be within acceptable levels. Of the 45 sample points, only one point returned a slightly elevated level of arsenic, a commonly found element in Michigan waterways.