On July 26th, Big Valley EPA staff sampled at 19 locations on the Clear Lake shoreline. Visible blooms were noted at 14 sites.We submitted 16 samples for Microcystin toxin and qPCR analysis, and analysis. Results are below. We are awaiting additional analysis on 2 sites: BP and CP.
We conducted microscopy on all samples and noted the following:
DOMINANT GENUS: Lyngbya sp.
SECONDARY GENUS: Gloeotrichia sp.
For more information on which cyanobacteria can produce which toxins: https://bit.ly/CyanobacteriaToxinsChart
Lab results are as follows: 4 sites with Danger levels of microcystin (above 20 µg/L): ELEM01, CLOAKS01, AP01, SBMMEL01. 6 sites with Warning levels of microcystin (above 6 µg/L): SHADY02, RED01, CLV7, LC01, JB, KP01. 1 sites with Caution levels of microcystin (above 0.8 µg/L): LPTNT. The remaining 3 sites had toxin levels below caution, were non detect or not likely due to other measured criteria.
For more details on the sampling event, go to https://www.bvrancheria.com/clearlakecyanotoxins
Please note that on July 27, 2022 Lake County issued guidance for those homes on the Oaks and Lower arms who supply their own drinking water from Clear Lake through their own pipes/intakes into the lake regarding the potential for cyanotoxins to be present in the tap water of those approximately 500 homes. (This does not apply to customers that get drinking water from water plants because several years of testing have shown that the drinking water supplied by the Public Water Systems have been able to remove cyanotoxins completely or to below a level of concern.) CalWATCH testing of self supplied systems last year showed that about 70% of homes had detectable microcystin in their tap water. http://www.lakecountyca.gov/Government/PressReleases/072722.htm
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