CLEAR LAKE CYANOTOXIN ISSUES

EPA

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 - 2022 SAMPLING RESULTS/LOCATIONS 

Final Results 5-4-22 map.jpg

 UPDATE ON CLEAR LAKE CYANOTOXIN LEVELS:

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WINTER LAKE MONITORING OCCURRING.  REDUCED NUMBER OF SITES SAMPLED MONTHLY.

Sudden cyanobacteria blooms noted during the first week of May led to a Special Sampling event at a few sites with blooms.  Water samples were taken at 4 sites, three with noticeable blooms.  

 

We conducted microscopy on all samples and those with the noticeable blooms had the following cyanobacteria: Woronichina sp. and Aphanizomenon sp. For more information on which cyanobacteria can produce which toxins: https://bit.ly/CyanobacteriaToxinsChart
 

We used Abraxis field strips to measure presence/absence of anatoxin-a and none showed detect of anatoxin-a.  We submitted the 4 samples for microcystin analysis and results are below. 

 

Identified map signage recommending restricted activity is based on CalOEHHA toxin trigger levels. 

CAUTION  / WARNING / DANGER   SIGNAGE

 5/4/22 Special Sampling RESULTS for

Microcystin:

DANGER (Anything above 20):

AP01                             >30 µg/L

JB                                   >30

WARNING (Anything above 6):

RED01                           15.2µg/L

 

CAUTION (Anything above 0.8):

no sites

BELOW CAUTION:

BVCL6                          ND

SITES NOT SAMPLED DURING THIS SAMPLING EVENT ARE NOT SHOWN ON THE MAP.

 Next sampling event will be May 10, 2022

Summer cyanotoxin monitoring (twice a month) is resuming in May 2022.

SITE ID NAME SPREADSHEET.JPG

EPA STAFF:

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