PORT TOWNSEND — The warning sign that was posted at Gibbs Lake was switched for one counseling caution Friday after tests found that the level of an algae-produced toxin had dropped below the safety threshold for a second week.
Anderson Lake stays closed because of high levels of toxins, while Lake Leland is safe, said Greg Thomason, Jefferson County environmental health specialist, Friday.
A warning sign was posted at Gibbs Lake, a popular swimming hole south of Port Townsend, on July 6 after results of a water-sample test discovered that the level of microcystin, a toxin created by blue-green algae, had risen above the safety threshold, to 7.9 micrograms per liter of water.
The safety threshold is 6 micrograms per liter of water.
Tests received Friday found that the level of microcystin was 0.82 micrograms.
The Friday before, the test found the level to be 1.98 micrograms.
“That’s the way it usually works,” Thomason said. “It peaks out and comes right down.”
Once an unsafe level of toxin is found in a lake, the department must receive two tests showing safe levels before changing the waterway’s status, he said.
“We need two weeks in a row,” Thomason said.
The most severe effect of microcystin is that some people could develop liver failure if they have consumed water containing the toxin over a long period of time.
Its short-term effects can include nausea, vomiting, diarrhea, skin irritation and burning, abdominal pain, blistering in the mouth and sore throat.
No anatoxin-a, the other algae-created toxin often found in East Jefferson County lakes, was discovered in Gibbs last week.
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.
Managing Editor/News Leah Leach can be reached at 360-417-3531 or at leah.leach@peninsuladailynews.com.
