Still dangerously poisonous, Anderson Lake nevertheless has improved since last week’s reported toxic load of more than 1,000 times the safe limit.
The latest test results of samples from the lake contain only nearly eight times the safe limit of the potent neurotoxin anatoxin-a.
“The numbers came down at Anderson, but it’s still above the warning level,” said Greg Thomason, Jefferson County environmental health specialist, on Friday, when he received test results of samples taken Monday.
“It’s definitely dangerous,” he said. “It’s still closed” to any kind of recreation.
Although no one should get in the water or fish in the 70-acre lake between Chimacum and Port Hadlock, the 410-acre Anderson Lake State Park surrounding it remains open for hiking, horseback riding, biking — all recreation not related to the lake.
Latest test results
The latest test results showed Anderson Lake contained 7.93 micrograms per liter of the algae-produced toxin.
The safe level is 1 microgram per liter.
Results June 24 showed 1,112 micrograms per liter of anatoxin-a, the highest level since 2008, when the lake set a world record — still unbroken — of 172,640 micrograms per liter of anatoxin-a, a quick-acting toxin that can kill in high doses.
Microcystin, which can damage the liver, decreased quite a bit in the latest test results.
The concentration was 6.5 micrograms per liter June 24. Friday’s results found 0.12.
The safe limit for microcystin, a slower-acting toxin than anatoxin-a, is 6 micrograms per liter, Thomason said.
Anderson Lake also has a thick bloom of six types of algae, five of which are known to produce toxins.
Others open for fishing
Test results show it’s still safe to eat fish from Lake Leland, Thomason said, though no one should get in the lake.
The results showed 0.05 milligrams per liter of both anatoxin-a and microcystin.
Leland,which is north of Quilcene, is posted with warning signs because it has a thick bloom of toxin-producing algae species, Thomason said.
Test results are about a week behind reality. The toxic load in any lake infested with the types of algae that can produce toxins could change quickly — and not be measured for several days.
Both Gibbs and Silent lakes tested below detectable levels for both algae-created toxins. Gibbs Lake is south of Port Townsend, while Silent Lake is on the Toandos Peninsula.
Caution signs are posted at those lakes because both contain algae known to produce toxins at times, even though the algae remains benign for now.
“It’s safe to catch fish, but be cautious about getting in the water because they have toxin-producing species in the water,” Thomason said.
“They could be producing toxins right now, as far as we know.”
Sandy Shore Lake south of Port Ludlow near state Highway 104 remains clear, Thomason said.
Fish that have been cleaned with the guts discarded can be eaten from lakes posted with either caution or warning signs.
Researchers don’t fully understand why certain types of blue-green algae will begin to produce toxins nor why the level of toxins increases or decreases.
Anderson Lake has been plagued with deadly toxins in the summer months since 2006, when two dogs died on Memorial Day after drinking lake water with a heavy concentration of anatoxin-a.
Anyone who observes an algae bloom at a lake is urged to phone the Jefferson County Public Health Department at 360-385-9444.
For more information about lake quality in Jefferson County, visit the environmental health website at http://tinyurl.com/6z64ofy.
No toxic blue-green algae has been reported in Clallam County, where health officers do not test for toxins. Instead, they visually monitor lakes for signs of algae bloom.
Algae blooms in Clallam County lakes should be reported to the Clallam County Department of Health and Human Services’ environmental health division at 360-417-2258.
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Managing Editor/News Leah Leach can be reached at 360-417-3531 or leah.leach@peninsuladailynews.