Peterborough toxins swept under the sediment

Pollutants flowing through Peterborough’s Little Lake may not all be as old as you think. Whenever or however they got there, the cleanup solution is a decision scientists can’t seem to agree on.

Little Lake has been recognized as a contaminated site by the provincial Ministry of the Environment and Trent University since the 1970s.

Throughout the past century, local factories have treated the waterway as a dump for industrial waste exposing the environment to high levels of toxins including metals and polychlorinated biphenyl (PCBs).

Pollution entering into the lake isn’t only a historical problem, it continues to be an issue with each rainfall. PCBs from the city’s current industries are washed up by stormwater, travel through a direct pipe and eventually spill into the lake.

Although Canada banned PCBs in 1977, legislation has allowed certain PCB equipment owners to continue using the machinery if they obey strict regulations. Since the ban, high exposure to PCBs has been linked to increased risks of cancer and other ailments.

One of the prime culprits for ongoing contamination is Peterborough’s General Electric according to Chris Metcalfe, a Professor and Chair of Environmental and Resource Studies at Trent University in Peterborough. Even if the company is responsible for some of the contemporary toxins in the lake, he doesn’t think they would ever be held legally accountable.

Parks Canada has jurisdiction over Little Lake as it is a federal waterway and part of the Trent-Severn system. No representatives were available for comment.

Dredging the lakebed is no longer a reasonable cleanup solution according to the most recent report conducted by the MOE in 2012. It argues stirring up the lakebed may cause more harm than it solves.

Not everyone agrees.

“They are very persistent and break down extremely slow,” said Metcalfe about the pollutants. “The hope is that they will be covered up by clean sediments, but if you are having continuous inputs from contaminated sources, than that is a whole other issue.”

The Environmental Science Group of the Royal Military College in Kingston conducted it’s own study on Little Lake in 2011. It recommended the opposite of the MOE — dredging the Peterborough Marina where toxins are most heavily concentrated.

The Ministry of Environment advises a large scale removal of sediments poses significant risk of exposing deeper, more contaminated layers.

“Immediate remediation of this area may not be necessary,” said Jamie Mugford from the Ministry of Environment and Climate Change Peterborough District Office. “Natural recovery may be a reasonable long-term option.”

The MOE is currently examining Peterborough’s former landfill site for additional active inputs of PCBs and metals. There is concern these toxins are draining into the waterway and flowing downstream into Rice Lake about 30 km south of the city.

This poses potential risk to the Hiawatha First Nation reserve located on Rice Lake’s north shore. The Ojibwa community harvests fish from the lake as a food source. The lake is also known as a major fishing location to sport fishers.

Rice Lake would face additional toxic stress if Peterborough’s lake was dredged according to Sera Weafer-Schiarizza. She published a 2009 report on Little Lake in partnership with Trent University and the Occupational and Environmental Health Coalition of Peterborough.

“If Little Lake is dredged, it will be stirred up and contaminants will be pushed downstream,”  Sera said. “Anything that happens in the lake affects the downstream lakes and rivers and wildlife.”

The MOE administered an update survey in 2015. Further decisions on the management of Little Lake are hinging on these results, expected to be released later this year.

Unless the 2015 report reveals dramatically increased levels of contamination, Little Lake may just be left to recover on its own.