Years of fireworks caused above-normal amounts of heavy metals in Lac Leamy
Higher heavy metal concentrations in Lac Leamy not a risk to human health, studies find
Fireworks shows that used to take place over Lac Leamy for years caused some higher concentrations of heavy metals and other contaminants, but not enough to be considered a risk to the people who swim or boat there.
Documents obtained by Radio-Canada show the National Capital Commission was interested in the impact the fireworks were having on the lake and beach.
The fireworks took place on the lake for 18 seasons and moved to a barge on the Ottawa River last year.
Geofirma Engineering did extensive testing on the lake in 2008, 2009 and 2010.
Copper, lead and other contaminants were found in higher concentrations after fireworks shows, but the spikes didn't last and the sediment at the bottom of the lake was more affected than the water itself, documents show.
"If [they] do a decade of fireworks and [they] do them monthly throughout the summer every year for 10 years, [that's] having a cumulative effect on ecosystems and that's certainly something we need to keep in mind whenever we're trying to understand these types of events and what impacts they're going to have," said Meaghan Murphy, the Ottawa Riverkeeper's staff scientist.
The NCC said Wednesday that the studies were not the reason the Sound of Light shows moved last summer to the Ottawa River.
Murphy said the river is a better place for the fireworks than the small, relatively stagnant lake.
"It's a river so there's a larger volume of water which is flowing through, so it's dispersing the chemicals that fall into the surface water and there's a lot of dilution that's happening," Murphy said, adding that the organizers of the fireworks have been cleaning the shoreline after events.