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 - 2021 SAMPLING RESULTS/LOCATIONS 

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 UPDATE ON CLEAR LAKE CYANOTOXIN LEVELS:

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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.  

CAUTION  / WARNING / DANGER   SIGNAGE

 09/7/21 RESULTS for

Microcystin:

DANGER (Anything above 20):

RED01                    160,377.50 µg/L

CLV7                           5,910.30

CL-3                             4,940.00

AP01                            4,857.00

LC01                               204.00

SBMMEL01                    54.80

JB                                      34.35

CLOAKS01                    29.39

SHADY01                       22.40

    SHADY01 ANATOXIN 25.95 µg/L WARNING LEVEL

WARNING (Anything above 6):

LA-03                              15.09 µg/L

LPTNT                            13.56

  LPTNT ANATOXIN 0.27 µg/L CAUTION LEVEL

OA-04                               8.76

KP01                                  7.53

                 

CAUTION (Anything above 0.8):

ELEM01                            5.67 µg/L

LUC01                               2.79

BVCL6                              1.84

BP                                      1.26

 

 

BELOW CAUTION 

KEYS03                             0.44 µg/L

   KEYS03 ANATOXIN 0.30 µg/L  CAUTION LEVEL

CL-1                                    0.18

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. 

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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