Why Was The Water Turning Black Near Niagara Falls?

Visitors to the Falls got a bonus surprise over the weekend when what appeared to be a black pool of water started to spread in the the Niagara River. The described "sludgy substance" was seen near the dock for the Maid of the Mist and it had a smell to it.

According to MetroSource, the Niagara Falls Water Board said "the black water was cause by a routine change in the wastewater treatment process at the Buffalo Road water plant." The water was cleared up by Sunday, but not before picture were captured.