Toxic algae blooms have tainted Vancouver, Lacamas and Round lakes off and on this summer, leaving people wary of dipping so much as a toe into these ordinarily popular recreation spots.
“We’ve had unreliable summertime water conditions,” said Kathy Gillespie of Friends of Vancouver Lake.
“When people see green water — to know they’re getting in their car and driving somewhere else is heartbreaking.”
The blooms tend to be sporadic, which makes it difficult to plan for fun at the lake. Just because the water looks icky doesn’t necessarily mean it’s unsafe –and just because it looks clear doesn’t mean it is.
“Algae are always present,” said Brian Schlottmann, program manager for Clark County’s environmental health division. Under certain conditions — for instance, when the water warms — cyanobacteria, also known as blue-green algae, will overtake benign strains of algae, he said.
“You have no idea of the toxicity just by looking at it,” he said. “Toxicity changes hour by hour.”
Clark County Public Health typically draws water samples on Mondays, but the results don’t come back until Thursdays. If toxin levels at a lake exceed state thresholds, the county places warnings for the following two weeks not to swim there and to avoid areas of scum when boating.
If toxin levels are extremely high, the county will place “danger” signs closing the lake altogether, as it did at Vancouver Lake Aug. 6 through 17.
Friends of Vancouver Lake raised money to inject an herbicide to eradicate an infestation of Eurasian milfoil, another threat to the lake and a nuisance to paddlers and rowers. The July treatment killed the underwater weeds, which then decayed and released nutrients into the lake, followed by several days with temperatures approaching 100 degrees.
“Then we saw the worst bloom we’ve ever seen,” Schlottmann said.
Overall, though, Vancouver Lake fared better this year than last, when weekly tests turned up toxins seven times.
Lacamas hasn’t had the same history of cyanobacteria blooms as Vancouver Lake, but weekly tests there this year detected elevated toxin levels 10 times beginning in April, according to state Department of Health records.
This year, the liver toxin microcystin has been the culprit at local lakes; it can cause abdominal pain, cramps and nausea.
In previous years, testing also detected anatoxin, which affects the nervous system, and can cause loss of balance and cognitive impairment.
“Kids and animals are a big concern,” Schlottmann said.
If you have visited a lake or river with your dog, and it becomes lethargic, excessively thirsty or seems to have lost its balance, visit the veterinarian right away.
For people, ingestion is a bigger risk than mere contact with the water. If you touch it, your skin may itch, burn or develop a rash. If you get water in your mouth, and start to feel sick to your stomach or dizzy, seek medical attention, Schlottmann said.
It’s also possible to inhale toxic algae, but far less likely, he said.
“As algae washes (ashore) and dries up, it can become a dust and get into the air. Breathing it could be problematic, but we don’t see that very often,” Schlottmann said. “But it’s important to keep dogs away from algae dried up on land.”
Pollution washing into lakes and warmer water temperatures create fertile conditions for cyanobacteria.
“There’s no silver bullet to fix algae,” Schlottmann said.
Stagnant water poses the highest risk, which is why Friends of Vancouver Lake would like to see a project to dredge to increase water flow from the flushing channel at the south end to Lake River at the north.
“I wish everyone would spend a day at the lake,” Gillespie said. “We’d have a groundswell of people saying, ‘Let’s take care of this.’ “