Northern Health is advising Charlie Lake homeowners and visitors to avoid potentially toxic blue-green algae blooms in the area.
The health authority issued a public health advisory on Aug. 5, saying the algae, known as cyanobacteria, can cause a range of illnesses from diarrhea and stomach cramps to eye and skin irritation.
Northern Health warns not to use the lake as an untreated water source for human or pet consumption -- even boiling the water does not kill the algae bacteria. It is also warning people to avoid swimming in water with visible blooms. And while Northern Health says consuming fish from the lake is still safe, people should limit their intake as fish may store toxins from the bacteria.
Madhu Nair, northeast regional team lead for public health protection, said the health authority was notified about the problem Thursday by a BC Parks ranger. Advisories have been put in place around the lake, he said, including Rotary Park and the boat launch, areas around Beatton Park, the golf course, and Montney Centennial Park.
Anyone who has come in contact with the water is encouraged to rinse and clean themselves. Anyone with symptoms, including headaches, nausea, sore throat, skin rashes or ulcers, is urged to see their doctor.
What is blue-green algae?
Blue-green algae is naturally occurring, however, feeds off excess nutrients in the water such as phosphates and nitrogen. Blooms can produce neurotoxins and hepatoxins that attack the nervous and respiratory systems, as well as the liver.
Bruce Kosugi, co-president of the Charlie Lake Conservation Society, says core sampling has found blue-green algae to be present in the lake for centuries.
"They've actually gone down so they can see what the lake was like 500 to 1,000 years ago. There's evidence of blue green algae then," he said.
Charlie Lake is considered eutrophic--rich in nutrients that support dense plant life, including algae, which choke out oxygen levels in the water. Blooms typically appear in the lake after the July long weekend, and the location of the blue-green algae is dependent on which way the wind is blowing, Kosugi said, as it does "tend to collect in areas where the wind might push it."
The Society is currently collecting water quality samples every two weeks in conjunction with the BC Lake Stewardship Society (BCLSS), BC Parks, the Ministry of Environment and the Ministry of Forest Lands and Natural Resources Operations.
"We note down when we do water quality sampling just how extensive the blue-green algae is," Kosugi said.
Kosugi says lake levels rose in the 1980s, causing shoreline erosion and killing much-needed vegetation to soak up excess nutrients in the lake. That vegetation is starting to make a come back, he said.
"The aquatic vegetation people are complaining about around the lake, about five to six years ago, a lot of that vegetation wasn't there," said Kosugi.
"What we think is happening is when they raised the water back in the early 1980s, there was a lot of shoreline erosion that possibly smothered those aquatic plants. So there's very little vegetation around the lake for 30 years. Now that erosion is stabilizing and the plants are able to re-establish, you have that plant growth, and it has taken up some of the nutrients the algae has fed on in the past."
Kosugi said the best way to limit the algae is to reduce the number of manmade nutrients going into the water by cutting back fertilizer use, reduce runoff into the lake, and keep natural vegetation along the shoreline.
The Society plans to continue its water sampling and will launch an aquatic plant survey, which will include blue-green algae, in the coming weeks. In the fall, the Society plans to hold a community meeting to talk about about its work and the health of the lake.