PORT TOWNSEND — Anderson Lake is closed due to an elevated level of the potent nerve toxin anatoxin-a found in a water sample.
Test results received this week from a water sample taken Monday found the toxin level is 1.28 micrograms per liter, which is above the state recreational threshold of 1 microgram per liter, in the lake between Port Townsend and Chimacum.
The bloom of cyanobacteria in the lake contains toxin-producing species of algae.
Anatoxin-a can result in illness and death in people and animals when ingested, according to Michael Dawson, water quality manager for Jefferson County Public Health, in a press release issued Friday.
Washington State Parks has posted “Danger – Keep Out of Lake” signs at access points to the park alerting visitors of the potential hazards of the lake. Recreational activities such as fishing, boating, and swimming are prohibited until the toxins dissipate and the lake is deemed safe for recreation.
Anderson Lake State Park remains open for other recreational activities such as horseback riding, hiking, biking and birdwatching.
Jefferson County Public Health has monitored local lakes for cyanobacteria since 2007 and Anderson Lake has had closures every year since then, including very high levels of toxin.
Over this period of time, three dogs have been confirmed to have died due to exposure to Anderson Lake water.
Anderson Lake was monitored for toxins this winter, and toxins were not detected but since April, bloom activity and toxin level have been steadily rising, Dawson said.
In addition to Anderson Lake, Leland, Gibbs, Tarboo and Crocker lakes all have been assessed for cyanobacteria activity this year and no evidence of blooms forming has been seen this season.
To check the status of Jefferson County Lakes and learn more about toxic cyanobacteria monitoring, see www.jeffersoncountypublichealth.org/723/Lake-Status or call 360-385-9444.
To check other lakes in Washington state, see www.nwtoxicalgae.org.
