A public health warning was issued Friday for Campbell Lake after water samples taken from the lake Sept. 7 showed significant levels of microcysin, a toxin produced by blue-green algae.
The samples, analyzed at the King County Environmental Lab, showed 21.9 micrograms per liter of the toxin — well above the state Department of Health’s public health concern threshold of 8 micrograms per liter, according to a Skagit County Public Health news release. The toxin can cause health effects from rashes to liver problems.
Warning signs have been posted around the lake, which is on south Fidalgo Island.
Blue-green algae can be visible on the top of the water, forming a colorful scum on the surface.
To avoid exposure, the public health warning for Campbell Lake includes: Do not swim or water ski; Do not drink lake water; Keep pets and livestock away; Clean fish well and discard guts; Avoid areas of scum while boating and recreating.
Campbell Lake is the second Fidalgo Island lake to be impacted by blue-green algae this summer. Nearby Pass Lake was closed to recreation in mid-August and remains closed.
While this is the ninth year toxins from blue-green algae have exceeded health thresholds in Pass Lake since Washington State Toxic Algae monitoring records began in 2021, this summer marks a first for Campbell Lake.
Beaver Lake south of Clear Lake has visual evidence of blue-green algae, but toxin levels remain below public health thresholds, according to water samples tested last week.
Still, health officials encourage users of Beaver Lake to avoid areas of scum and intensely colored water. A caution sign has been posted at the public boat ramp.