LAKE COUNTY, Calif. — Health and tribal officials are reporting that, due to persistent drought and heat, they are finding unprecedented levels of cyanotoxins in some areas of Clear Lake.

For Lake County residents with individual water systems that draw water directly from the lake using a private intake, drinking water may become unsafe when high levels of toxins are present, Lake County Health Services reported.

Of particular concern are those with individual water systems who live around the Sulphur Bank Mine, and along the shore of Clear Lake’s Lower and Oaks Arms.

Similar to last year, potentially harmful concentrations of cyanotoxins have been identified in these areas of the lake.

Public health and water quality experts are concerned there may be impacts to the health of those using individual water systems, if they are not effectively filtering out these toxins.

There is no easy fix if you are getting your water in this way —boiling or putting chemicals in the lake or tap water does not eliminate the toxins.

Public water systems are able to effectively remove toxins, and will continue to provide tap water which has gone through a multifaceted treatment process. Even public water systems which draw water from Clear Lake as their raw water source continue to provide water that is safe for consumption, and continually monitored to maintain compliance with state water quality requirements.

Officials urge residents to contact their public water system if they would like more information.

Last year, in collaboration with local officials and the State Water Resources Control Board, Golden State Water Co. and Mt. Konocti Mutual Water Co. established filling stations to provide safe, drinkable water to affected community members.

 

This water continues to be available to meet very basic household needs such as drinking, cooking, brushing teeth, preparing food, mixing baby formula, making ice and giving water to pets. Those who choose to utilize these generously provided resources are asked to please limit consumption to 25 gallons per week per household.

Affected residents should bring their own clean containers that are meant for beverage storage to whichever location is most convenient:

• 10680 Lakeshore Drive, Clearlake: provided by Golden State Water Co., 1-800-999-4033;
• 4980 Hawaina Way, Kelseyville: provided by Mt. Konocti Mutual Water Co., 707-277-7466.

If you live outside of the areas specified, and you have an individual water system with a private intake that draws water directly from Clear Lake, it is important to maintain awareness of current water quality conditions and assess your risk. Recent monitoring data is available here: www.bvrancheria.com/clearlakecyanotoxins.

Big Valley EPA’s robust Cyanotoxin Monitoring Program collects samples from testing sites around Clear Lake at biweekly intervals during the summer months. They sampled 19 testing sites along Clear Lake’s shoreline on July 11 and received three samples from the lake’s interior testing sites, which were sampled by the Lake County Water Resources Department on July 6.

Microscopy conducted on these samples determined the dominant genus of cyanobacteria present was Microcystis sp. The chart below lists cyanotoxins and the cyanobacteria that produce them, along with potential health effects from exposure to the toxins.

At some levels of cyanotoxin concentration, it is safe to use water to wash hands and shower; at higher levels (>0.3 µg/L), these activities may be harmful to the health of vulnerable individuals.

Please be cautious when bathing infants and young children, as they may swallow water. Do not drink or use water from any appliance connected to your water supply lines. This includes the water and ice dispensers in your refrigerator, freezer and dishwasher.

For households getting their tap water from individual water systems with private intakes from Clear Lake (and who have not previously participated), testing for contaminants such as cyanotoxins, nitrates, coliform bacteria, and herbicides is available through Big Valley EPA’s Cal-WATCH program detailed here: www.cal-watch.org.

For additional information about cyanotoxins and harmful algal blooms, please visit the following websites:
Centers for Disease Control and Prevention (CDC): www.cdc.gov/habs/index.html
Environmental Protection Agency (EPA): www.epa.gov/cyanohabs
County of Lake Cyanobacteria Webpage: www.lakecountyca.gov/Government/Directory/WaterResources/ClearLake/Cyanobacteria.htm