PORT TOWNSEND — Toxin levels were high in the last test of the season of Anderson Lake water.
Anderson Lake water samples taken Oct. 5 contained anatoxin-a and microcystin toxins at levels above state recreational guidelines, said Michael Dawson, lead environmental health specialist for the Jefferson County Water Quality Program, in an email.
That was the final test the county will perform this year on lake water toxins, Dawson said. Testing is expected to resume in the spring.
Anatoxin-a is a fast-acting nerve poison that can kill within four minutes of ingestion and microcystin can produce a rash, or respiratory symptoms on exposure. Both are produced by blue-green algae.
Anderson Lake, which is near Chimacum, has been closed to fishing and other water recreation since May 7 because of high toxin levels. The state park around the lake remained open.
In addition to high toxin levels, the lake also has a persistent bloom of algae, Dawson said.
Lake Leland
Lake Leland, which is near Quilcene, also has a persistent bloom, with patchy areas of surface scum dominated by toxin-producing algae species, Dawson said.
Tests, however, show that toxin levels were below recreational guidelines.
Toxins can arise quickly, however.
“Often, toxin levels increase for days or weeks even as algae blooms dissipate,” Dawson said.
“It is difficult to predict the conditions of lakes more than a few weeks ahead,” he added.
“However cooler fall temperatures typically slow the growth of algae.”
Jefferson County Public Health recommends that people avoid areas of scum on Lake Leland.
Warning signs have been posted.
Gibbs Lake
Caution signs are up at Gibbs Lake, a catch-and-release trout lake near Chimacum, because the water contains algae species known to sometimes produce toxins.
An earlier toxic bloom there has cleared up, Dawson said.
The lake was closed for a few weeks beginning in August because of high levels of microcystin. The county park around it remained open.
The state Department of Ecology reported last summer that lakes and rivers in the Puget Sound area were experiencing more intense and widespread algae blooms than in earlier years.
The department attributed the phenomenon at least partially to warmer water created by the drought that gripped the state then.
Warmth increases the growth of blue-green algae, which is usually benign; some species can begin to produce toxins.
Researchers do not know what triggers the toxin release.
Algae growth also is fed by nutrients such as phosphorus, which is found in large amounts in Anderson Lake.
Lake users are encouraged to call Jefferson County Public Health at 360-385-9444 if algae blooms are seen to be grower thicker.
For more information about Jefferson County lakes, visit http://tinyurl.com/jeffersonlakequality.
Toxin-producing blue-green algae has not been spotted in Clallam County.
Report algae blooms in Clallam County by phoning 360-417-2258.
For fishing seasons and regulations, see the state Department of Fish and Wildlife website at www.wdfw.wa.gov.
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Executive Editor Leah Leach can be reached at 360-417-3531 or at lleach@peninsuladailynews.com.
