PORT TOWNSEND — Gibbs Lake south of Port Townsend has been closed for recreation including fishing, boating, and swimming because of high levels of the toxin microcystin.
Microcystin, which is produced by blue-green algae, can cause skin irritation, nausea and muscle weakness if touched and liver damage if swallowed over a long period of time.
Lab tests from a sample taken Monday show that the microcystin level is 14 micrograms per liter, which is above the state recreational criteria of 6 microgram per liter.
Jefferson County Parks and Recreation closed the lake for all recreation and urged visitors to Gibbs Lake County Park — which remains open for hiking, biking and horseback riding — to keep pets out of the water, Michael Dawson, lead environmental health specialist for the Jefferson County Water Quality Program, said Thursday.
The county department has posted danger signs at lake access points.
Jefferson County Public Health has monitored local lakes for blue-green algae toxins seasonally since 2007.
Monthly monitoring of Anderson, Gibbs, and Leland lakes began in April this year.
No algae bloom was observed at Gibbs Lake earlier this summer, Dawson said.
State rangers closed Anderson Lake in May because of high levels of anatoxin-a, a potentially lethal nerve toxin, which also is produced by blue-green algae. The state park around the lake remains open.
Lake Leland has a light algae bloom, but toxin levels have remained low. A caution sign is up.
Blue-green algae, which occurs naturally, can begin at times to produce toxins in a process researchers still don’t understand.
Toxins can be present only after an initial bloom, Dawson has said, but a bloom can die off and, although the lake looks clear, it could be poisoned.
For more information about Jefferson County lakes, visit http://tinyurl.com/jeffersonlakequality.
Those who see a bloom on a lake are urged to report it to 360-385-9444.
County health officials urge lake visitors to avoid contact with algae blooms.
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 www.wdfw.wa.gov/fishing.
