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 6-14-22 map.jpg

 UPDATE ON CLEAR LAKE CYANOTOXIN LEVELS:

================

SUMMER MONITORING OCCURRING, NEXT SAMPLING EVENT JUNE 28, 2022

On June 14, Big Valley EPA staff sampled at 19 locations on the Clear Lake shoreline and received samples from 9 locations in the interior of the Lake from UC Davis (sampled 6/13/22) and Lake County Water Resources Department (sampled 6/9/22).  Visible blooms were noted at 6 sites. 

 

We conducted microscopy on all samples and noted the following:

  • DOMINANT GENUS:  

Microcystis sp. 

  • SECONDARY GENUS:

Gloeotrichia sp.

  • ADDITIONAL GENERA NOTED:

Woronichinia sp.

Aphanizomenon sp. 

 

For more information on which cyanobacteria can produce which toxins: https://bit.ly/CyanobacteriaToxinsChart
 

We submitted 20 samples for Microcystin toxin and qPCR analysis, and analysis.   Results are below and 1 site has toxin results pending (SHADY01).

 

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

CAUTION  / WARNING / DANGER   SIGNAGE

 6/14/22 RESULTS are for Microcystin unless otherwise noted:

DANGER (Anything above 20):

 SBMMEL01               790.00 µg/L

ELEM01                         84.21

RED01                            39.40

 

WARNING (Anything above 6):

JB                                 17.62 µg/L

CLOAKS01                16.87

AP01                             6.14

 

CAUTION (Anything above 0.8):

LA-03                             4.38 µg/L

CL-3                               3.45 

OA-04                            2.69

CL-4                               2.11

BELOW CAUTION:

LUC01                           0.53 µg/L

CL-1                               0.29

CLOAKS01                   0.15 

 

 

NO DETECT/NOT LIKELY:

BP

LC01

CLV7

CP

BVCL6

GH

KP01

HB

KEYS03

LPTNT

NR-02

RODS

UA-01

UA-06

UA-08

     

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

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

Alicia Castellanos, Environmental Assistant

Richard White, Pollution Prevention Coordinator