Vancouver Lake’s popular swim beach was closed for a few hours Thursday as technicians applied algaecide to the lake’s surface. This is the first time a proactive treatment has been tried to prevent the toxic algae blooms that have become commonplace at the lake.
“Our goal for this treatment is that it will help reduce the prevalence of algae at the Vancouver Lake swim beach. We’re also hoping that, through this treatment, we’ll learn more about how effective the chemical is in reducing harmful algae,” Devan Rostorfer, division manager for Clark County Public Works, said Thursday.
A similar treatment was done last week at Lacamas Lake.
The county hired AquaTechnex, a California-based firm with offices in Washington that specializes in aquatic plant management, to apply the algaecide. Technicians spent about two hours applying the algaecide, Phycomycin SCP, via a slurry system on a boat. Fanjets were used to spread the slurry across the surface of the lake.
The active ingredient in the algaecide is sodium carbonate peroxyhydrate, a combination of sodium carbonate and hydrogen peroxide. When applied, the algaecide opens the algae cell and kills it. Then the hydrogen peroxide breaks down into water and oxygen.
Two additional treatments are planned this summer, although specific dates have not been scheduled. The treatments are part of Clark County’s Vancouver Lake Management Plan. Rostorfer said the pilot treatment will help the county further refine the management plan, which will help keep the beach open.
“We’re learning a lot this summer, with the goal that — through learning — we’ll be able to discover a successful pathway forward for long-term beach management,” Rostorfer said.
Harmful algae blooms have been a recurring problem, typically during warm summer months, at both Vancouver and Lacamas lakes. The county has had to issue public health advisories or close the waters to swimming because of the presence of cyanobacteria and cyanotoxins released by blue-green algae.
Blue-green algae can pose a significant health risk if cyanobacteria or toxins are ingested, inhaled or come into contact with skin. Inhaled bacteria or toxins can cause wheezing, coughing, chest tightness and shortness of breath. Skin contact can lead to rash, itching, blisters and eye irritation.
If water with cyanotoxins is accidentally swallowed, symptoms can include abdominal pain, diarrhea, vomiting, numbness of the lips, tingling in fingers and toes, and dizziness. The toxins can be fatal to pets that drink the water.
“We’re really excited that this is the first time that Vancouver Lake is being treated for harmful algae blooms,” Rostorfer said. “Treatments like this have been implemented regularly in other places in Washington state and across the United States.”
The decision to treat the lake came after algae scum was spotted on the lake’s surface.
“Earlier this week, Public Health was out in the field, like they are routinely, and they observed visible algal scum on the surface of the lake and took a water sample. … It was visual evidence that a bloom could be forming,” Rostorfer said. “We’re still waiting on those test results to tell us exactly how much algae is in the water.”
Although the algaecide does not pose a risk to people or pets, Public Health issued an advisory as a precaution.
As a reminder, dogs and other domestic animals — except service animals — are not allowed on the beach or surrounding grassy area of Vancouver Lake Regional Park between April 1 and Oct. 31.
“We’re eager to see how the lake responds to the treatment, which we should know sometime next week,” Rostorfer said.
More information is available at https://bit.ly/4c4cHSm.
