A Dartmouth councillor wants to know why Lake Micmac is looking red.

Coun. Andrew Younger (East Dartmouth-The Lakes) is calling on the provincial Environment Department to launch a full investigation of run-off believed to be from a neighbouring commercial site.

During two recent rainstorms, runoff allegedly coming from lands owned by Dartmouth Crossings Ltd. and leased by the Lafarge asphalt plant, has resulted in large red slicks on the lake, he said in a release Wednesday.

"During the April 23 rain event, the slicks reached hundreds of metres out into the lake," he said. "This is disturbing to both me and to residents."