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 9-20-22 map.jpg

 UPDATE ON CLEAR LAKE CYANOTOXIN LEVELS:

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

SUMMER MONITORING OCCURRING, NEXT SAMPLING EVENT OCTOBER 4, 2022

On September 20, Big Valley EPA staff sampled at 17 locations on the Clear Lake shoreline and received 6 samples from UC Davis from their interior of the lake sites sampled 9/12/22. Visible blooms were noted at 9 sites. 

 


Microscopy was conducted in house, with Microcystis sp. as the dominant cyanobacteria genus.

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

We submitted 16 sites for toxin analysis of Microcystin, Anatoxin, and Saxitoxin cyanotoxins.  Results are below.  

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

CAUTION  / WARNING / DANGER   SIGNAGE

9/20/22 RESULTS are for Microcystin unless otherwise noted:

DANGER (Anything above 20):

RED01                         84.01 µg/L

CLOAKS                     68.05

GH                               64.17

 

WARNING (Anything above 6):

LPTNT                     19.10 µg/L

Saxitoxin               0.02

OA-04                        9.08

AP01                          8.07

ELEM01                    6.69

 

CAUTION (Anything above 0.8):

BP                              5.99 µg/L

KP01                          2.27

LC01                          2.18

SBMMEL01               1.98

CLV7                          1.87

BVCL6                       1.48

SHADY01                  1.01

PRESENCE OF POTENTIALLY TOXIN PRODUCING CYANOBACTERIA, CAUTION SIGNAGE:

LA-03

NR-02

UA-01

UA-06

BELOW CAUTION:

JB                             0.45 µg/L

CP                           0.21

HB

LUC01

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 Data Coordinator

Richard White, Pollution Prevention Coordinator

Alicia Castellanos, Environmental Assistant

Nijoel McCloud, Environmental Technician