Health officials urge caution due to toxic blue green algae in Clear Lake

Lake County Public Health officials are urging caution when recreating on Clear Lake because of increasingly high levels of dangerous toxins produced by cyanobacteria at several test locations.

One site in Clearlake Oaks showed the highest level of a liver toxin called microcystin ever recorded in Clear Lake. Another site in the Clearlake Keys had record-high concentrations of Anatoxin-a, a fast-acting neurotoxin, but the level was still within the “caution” range, according to data from the Big Valley Band of Pomos Environmental Protection Department, which leads the testing effort around the lake.

Densities of what are often called blue-green algae have been increasing throughout the summer as the lake level has continued to drop and high temperatures, which often contribute to cyanobacteria blooms, have persisted.

Substances produced by the blooms can include toxins that are dangerous to humans, pets and livestock.

They include microcystin, which was measured at “dangerous” concentrations at nine locations around the lake. Microcystin also was detected at four sites at levels requiring warning signs under state standards.

In addition, Anatoxin-A, which can prove quickly fatal if ingested in high enough volume, was found at caution levels at three locations.

Public Health officials recommend boaters and other lake users avoid direct contact with the water and follow all posted signs. They also urged visitors to avoid ingesting water and to protect children and pets, who are at greatest risk due to their size and behavior.

More information is available at bvrancheria.com/clearlakecyanotoxins?fbclid=IwAR3WXzQsfY4EHVRPNJG-qZ18-oDIgfxpDUZdboJWh-bMXbfZ0503eRPi9Bw.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.