The cause of a blue-green algae bloom in Jackfish Lake remains a mystery, but the Department of Environment and Natural Resources believes it could be the result of landfill run-off. - Meagan Leonard/NNSL photo |
Don't blame landfill for toxic algae: city
Conditions in Jackfish Lake could be due to climate change, drought
Meagan Leonard
Northern News Services
Wednesday, July 15, 2015
SOMBA K'E/YELLOWKNIFE
There is nothing to indicate runoff from the city's landfill is to blame for a toxic algae bloom in Jackfish Lake, say city officials.
In June the Department of Environment and Natural Resources put in a request to the Mackenzie Valley Land and Water Board to require th city to undertake additional testing around the landfill, but Director of Public Works Chris Greencorn said although the city intends to comply, it is too early to point fingers. He says currently there is no data available which would support ENR's claim as water levels have been too low to conduct testing for the last few years.
"At this point we see no indication or evidence whatsoever to lead us to believe this is caused by city operations of any kind," he said, adding the testing location for run-off into Jackfish Lake has been dry for almost three years due to drought conditions.
He said water volumes have simply been too low to have the impact ENR is suggesting, so he is skeptical the algae was caused by the landfill.
"We've had very little rain for the past two years so we find it hard to believe that run-off in these quantities would be causing this type of algae bloom," he said. "Maybe this algae was always there but now it's more visible because the water is at an all-time low."
Blue-green algae has been present in Jackfish Lake the last two seasons and is said to be the result of high phosphorous levels which have created a "hyper eutrophic aquatic ecosystem," according to ENR in its letter to the land and water board.
When detergents, fertilizers or sewage run off into a lake, the increase in nutrients in the water causes massive growth and decay of plants and algae. The effect can also result after extended periods of warm weather.
In both cases, an overabundance of plant matter depletes the water's oxygen, thereby reducing its quality and threatening fish species.
Ken Ashley is an expert in aquatic ecology at the British Columbia Institute of Technology in Burnaby, B.C., and says the algae could easily have been caused by either the landfill or climate change, but only testing will be able to determine for certain. However, he said it is unlikely the algae appeared overnight and instead was part of an augmented shift in the ecosystem.
"Lakes have tipping points," he said. "A lake can be accumulating low level stress over a period of time and then it's the straw that broke the camel's back and it will flip over into the condition it's in now and it may stay there for a long time unless you make some pretty
significant efforts."
Because blue-green algae has been identified by Health Canada as containing a human carcinogen, its presence in the lake - particularly a popular fishing location - is troubling, says Ashley.
"If a lake starts producing blue-green algae that's (bad) news," he said. "Not only does it use oxygen at the bottom of the lake, it also produces toxins that can be lethal to humans, fish and wildlife."
Daniel Lafond first brought the algae to Yellowknifer's attention in May when he noticed a reddish-brown film on the lake surface. He says he doesn't see much of it anymore and has continued to fish at the site.
"I don't think that stuff is harming because it disappeared," he said. "I don't have any concern about it anymore."
Greencorn said the city is committed to working with the land and water board and the GNWT to determine the cause of the algae and in response to their request, will add two additional sampling stations and start testing phosphorous levels this year.
The new sampling spots will be located at Fault Lake and Vicinity Lake where run-off enters the water.
ENR spokeswoman Judy Mclinton told Yellowknifer in an e-mail the department is just gathering information at this point to determine a causing agent.
"Information gathered through monitoring will provide ENR with a better understanding of what's happening in this aquatic system," she said.
