Algae on Sudbury lakes driven by historical lack of sewage treatment, scientist says

A scientist from Laurentian University's Living with Lakes Centre — and long-time Simon Lake resident — says algae problems in the western part of the city are still largely driven by lack of sewage treatment in Sudbury's earlier years.

Until the early 1970s, sewage went directly into Kelly Lake — upstream of Mud, Simon and McCharles lakes

Something called phoslock is being considered as a solution to the perennial algae problem in Greater Sudbury's Simon Lake. It would see tonnes of clay dumped into the lake, trapping phosporous in the lake bottom, so algae can't feed on it. So far, it's only been approved for use in a bay of Lake Huron. (City of Greater Sudbury)

A scientist from Laurentian University's Living with Lakes Centre — and long-time Simon Lake resident — says algae problems in the western part of the city are still largely driven by lack of sewage treatment in Sudbury's earlier years.

David Pearson, an earth sciences professor at Laurentian University's Living With Lake Centre, has lived on Simon Lake for more than 30 years.

"It does smell like something is rotting," he said. "If you are within about 50 or 60 feet of the lake, you know that you are next to something that is rotting."

David Pearson is a professor of earth sciences professor at the Living with Lakes Centre in Sudbury. (Roger Corriveau/CBC)

The smell comes from thick algae that has died at the surface of the lake, Pearson said.

A town hall meeting was held Wednesday for residents on Mud, Simon and McCharles lakes to ask questions of city staff and health officials about the cause of the algae problem.

Pearson said that cause is largely due to Sudbury's history with sewage treatment.

Until the early 1970s, Sudbury did not have a proper sewage treatment plant, he said, adding sewage went directly into Kelly Lake, which is upstream of Mud, Simon and McCharles lakes.

"Off downstream to Kelly Lake, and into Mud, and into Simon and into McCharles went the organic matter from Sudbury's toilets," Pearson said.

The algae in those lakes is thriving because of the phosphorus that is still being released from that organic matter, he said.

A public meeting was held Wednesday night to address concerns about ongoing problems with smelly algae on Simon Lake and Mud Lake in the western end of Sudbury. (City of Greater Sudbury)

Current sewage treatment

Some residents have also raised concerns about the current state of the city's wastewater treatment system, which does allow some partially treated effluent into the river and lake system during heavy rainfalls.

"[During] the extreme heavy rain events, in the spring season especially, there are a lot of bypasses where the effluent is only partially treated," said Linda Heron, with the Vermillion River Stewardship group, adding there is concern this contributes to the existing problem.

Pearson said the overages in the current system do have a small effect on water quality, but he still believes the problem won't be resolved until the larger source of phosphorus eventually fades away on its own.

Pearson spoke with CBC Sudbury radio's Morning North host Markus Schwabe about his experience living on Simon Lake and the science behind the algae.


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