PORT TOWNSEND — Gibbs Lake is now off-limits for swimming.
Warning signs went up Friday at the popular swimming hole south of Port Townsend 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.
“People should not swim in the lake now,” said Greg Thomason, Jefferson County environmental health specialist, on Friday just before he left his office to erect the new signs.
“Stay out of the water.”
The level of microcystin jumped to 7.9 micrograms per liter of water last week after having been measured at only a trace the week earlier, Thomason said.
The safety threshold is 6 micrograms per liter of water.
The most severe effect of microcystin is long-term. Some people who have consumed water containing the toxin over a long period of time have developed liver failure.
But the toxin has short-term effects, too, Thomason warned.
Those effects can include nausea, vomiting, diarrhea, skin irritation and burning, abdominal pain, blistering in the mouth and sore throat, he said.
Microcystin can enter the body through the skin — and through the lungs, “even breathing the mist from the shore,” Thomason said.
Gibbs Lake is not closed. While the warning sign counsels no swimming, it says that boating and fishing can be done
if boaters avoid areas of scum and if fish are well-cleaned and guts are discarded.
Warning signs also say that “algae toxins may be present in fish tissue,” and direct people to call the Jefferson County health department at 360-385-9444 for more information.”
No anatoxin-a — another blue-green algae-produced toxin commonly seen in East Jefferson County lakes — was found in Gibbs Lake.
High levels of anatoxin-a, a quick-acting nerve toxin, have kept Anderson Lake closed since May 3.
Only the lake in Anderson Lake State Park, which is between Port Townsend and Chimacum, is closed to recreational use.
The 410-acre park surrounding the lake remains open. A Discover Pass is needed to park there.
Lake Leland, north of Quilcene — the other lake tested last week — remains safe, Thomason said.
Weekly tests are announced on Friday after samples are taken on Monday.
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.
