Water Resources Protection Program
Presentations on the Cyanotoxin Monitoring Program:
Cyanobacteria Impacts to Tribal Water Uses
CLEAR LAKE CYANOTOXIN ISSUES
The Environmental Protection Department (Big Valley EPA) researches, plans, funds, and implements projects that protect the Tribe’s environment. Return to Big Valley EPA's page.
The Big Valley Band of Pomo Indians began a cyanobacteria and cyanotoxin monitoring program on Clear Lake in 2014 with another shoreline Tribe, Elem Indian Colony. Together the two Tribes' Environmental Departments have collaborated with equipment, resources and time to test the water for toxins produced by cyanobacteria (AKA “Blue Green Algae”). These toxins are called cyanotoxins and can be neurotoxins, liver toxins and skin toxins. The Tribes began this program because despite the fact that Clear Lake had thick, noxious blooms covering its surface every summer since 2009, there was no regular and active monitoring of these blooms for the cyanotoxins that the California Office of Environmental Health Hazard Assessment (OEHHA) had reviewed and suggested Action Levels for in 2012, and for which the World Health Organization provided guidance regarding exposure in the 1990’s. OEHHA's Report
CURRENT RESULTS - 2021 SAMPLING RESULTS/LOCATIONS
UPDATE ON CLEAR LAKE CYANOTOXIN LEVELS:
HIGHEST MICROCYSTIN TOXIN LEVEL ON CLEAR LAKE FOR THE SECOND SAMPLING EVENT IN A ROW: 160,377.50 µg/L
HIGHEST ANATOXIN-A TOXIN LEVEL ON CLEAR LAKE FOR THE SECOND SAMPLING EVENT IN A ROW: 25.95 µg/L
At our last sampling event on 9/7/21, we collected water samples from 15 sites on the lake. We also received water samples from UC Davis (collected 9/3) and Lake County Water Resources Department (collected 9/8). 7 of the 15 sites had evidence of bloom.
We submitted most of the samples for microcystin analysis, and 3 sites for Anatoxin-a analysis. A few locations from UC Davis and LCWRD were in areas with other submitted lab samples, so we did not submit 4 samples for toxin analysis.
We conducted microscopy on all samples. Most of the sites had Microcystis as the dominant genus present but we were also seeing some Planktothrix sp. , Aphanizomenon sp., and Dolichospermum sp. For more information on which cyanobacteria can produce which toxins: https://bit.ly/CyanobacteriaToxinsChart
Identified map signage recommending restricted activity is based on CalOEHHA toxin trigger levels. All Anatoxin-a Detects require at least Caution Signage.
09/7/21 RESULTS for
DANGER (Anything above 20):
RED01 160,377.50 µg/L
SHADY01 ANATOXIN 25.95 µg/L WARNING LEVEL
WARNING (Anything above 6):
LA-03 15.09 µg/L
LPTNT ANATOXIN 0.27 µg/L CAUTION LEVEL
CAUTION (Anything above 0.8):
ELEM01 5.67 µg/L
KEYS03 0.44 µg/L
KEYS03 ANATOXIN 0.30 µg/L CAUTION LEVEL
SITES NOT SAMPLED DURING THIS SAMPLING EVENT ARE NOT SHOWN ON THE MAP.
Summer sampling of 2x month is occurring. Next sampling event will be September 21, 2021.
Sarah Ryan, Environmental Director (707)263-3924 x132 and (707)349-4040 cell
Alix Tyler, Water Quality Program Manager
Katherine Schrade, Environmental Specialist
Richard White, Solid Waste Technician