PORT TOWNSEND — The level of a fast-acting nerve poison in Anderson Lake has leaped to more than 500 times the warning level, according to results of tests taken last week.
“A serious bloom is happening, and the toxins have jumped way, way up,” said Greg Thomason, Jefferson County environmental health specialist, on Friday.
“It’s the highest it’s been this season at Anderson Lake.”
The lake between Port Townsend and Chimacum, which was closed May 3 this year because of elevated levels of toxins produced by blue-green algae, remains closed to recreation, though the 410-acre park surrounding it stays open to the public.
The level of anatoxin-a, which can quickly cause convulsions and stop breathing, was measured at 534 micrograms per liter of water.
Beyond the threshold
The safety threshold is 1 microgram per liter.
The level found the week before was 24.8 micrograms per liter of water.
“So it’s taken a huge jump,” Thomason said.
The level of microcystin — another algae-produced toxin commonly found in East Jefferson County lakes — came up in Anderson Lake, though it was way below the danger threshold of 6 micrograms per liter.
Microcystin can cause skin irritation and, if ingested over a period of many years, can result in liver failure.
It was found to be at 1.4 micrograms per liter in Anderson Lake in the latest results.
None was detected in the tests the week before.
“It’s summertime, and things are cooking,” Thomason explained.
Sunny weather and warm temperatures encourage the growth of blue-green algae when sufficient nutrients, such as phosphates, are present.
But only some species of algae produce toxins — and not all the time.
What prompts benign algae to begin pumping out poison into a waterway is a mystery — one that researchers all over the world are attempting to solve, Thomason said.
That’s why caution signs are up at Leland, Gibbs and Crocker lakes.
The levels of algae-produced toxins are low, but the species of algae in all three lakes are types known to at times begin to create toxins.
If they do, the only way to know if a lake is poisoned is through tests.
Samples are taken every Monday and sent to King County Environmental Lab, which issues results Fridays — so results are at least five days behind reality.
Use caution
Thomason urged users of Leland Lake in particular to use caution this week.
“Leland is still safe, but the anatoxin there shot up over 10 times what it was last week,” Thomason said.
The level of anatoxin-a in Leland, which is north of Quilcene, was measured at 0.52 micrograms per liter — a rise from the week before when it was 0.05.
Even though it’s below the danger level, “it’s also shooting up fairly quickly,” Thomason said.
He noted that the last sample was taken June 11, and the next time the county will be notified of any increase in toxin level will be June 22.
“Because of the lag time, we ask people to be very cautious,” he said.
“If you see a pea-soup kind of green scum, just stay away from the water.
“Even as I speak, they could be at the danger level, and we wouldn’t know it.”
No microcystin was detected in Lake Leland.
Gibbs Lake
The latest testing showed that toxin levels in Gibbs Lake, south of Port Townsend, are still very low, with anatoxin-a at 0.03 and microcystin at 0.11.
No other lakes were sampled last week.
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.
A Discover Pass — which is $10 for one day or $30 for an annual pass, and which can purchased at state parks — is needed to visit state parks.
Report algae blooms in Clallam County by phoning 360-417-2258.
Report algae blooms in Jefferson County by phoning 360-385-9444.
For more information about lake quality in Jefferson County, visit the environmental health website at http://tinyurl.com/6z64ofy.
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Managing Editor/News Leah Leach can be reached at 360-417-3531 or at leah.leach@peninsuladailynews.com.
