- Lake County Health Services
- Posted On
County issues update on water advisory, cyanotoxin testing
LAKE COUNTY, Calif. — A drinking water advisory remains in effect for households with individual water systems which use private intakes to draw from Clear Lake along the shoreline of the Lower and Oaks arms.
County officials said there is no simple remedy if you are getting your water in this way — boiling or putting chemicals in the lake or tap water does not eliminate the cyanotoxins.
Public water systems remain unaffected by this advisory and continue to provide customers with a safe supply of drinking water absent of cyanotoxins, which meets state and federal water quality standards.
Twenty five gallons per week of drinking water is available at filling stations for affected households, which is generously being provided by Golden State and Mt. Konocti Mutual Water Companies at the following locations:
• 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.
On July 26, Big Valley Environmental Protection Agency sampled 19 locations on Clear Lake’s shoreline. Visible harmful algal blooms, or HABs, were noted at 14 of the locations sampled.
Sixteen samples were submitted for microcystin toxin analysis and qPCR analysis which indicated the following:
• Five locations indicated the presence of danger levels (>20 µg/L) of cyanotoxins;
• Six locations indicated warning levels (>6 µg/L);
• Two location indicated caution levels (>0.8 µg/L);
• Three locations had toxin levels below caution levels.
The five locations with danger levels of cyanotoxins are the following (also see red danger indicators on the map provided):
• Austin Park (AP01, Lower Arm);
• Buckingham Park (BP, Lower Arm);
• Clearlake Oaks (CLOAKS01, Oaks Arm);
• Elem Indian Colony shoreline (ELEM01, Oaks Arm);
• Sulphur Bank Mercury Mine shoreline (SBMMEL01, Oaks Arm).
Recent cooler weather may have temporarily reduced cyanotoxin levels in Clear Lake. Many visible HABs have somewhat dissipated in recent days, but they will likely reappear soon as the summer heat continues.
Officials noted that, if future sample analysis indicates an improvement in the level of cyanotoxins in Clear Lake, this does not ensure it is safe to drink water from privately managed individual water systems.
Testing has shown other contaminants may also be present in these systems. People using individual water systems must make sure they are regularly maintained and tested; for cyanotoxins, nitrates, coliform bacteria and herbicides.
For households getting their drinking water from individual water systems which use private intakes to draw from Clear Lake (and who have not previously participated), testing for these contaminants is available through Big Valley EPA’s Cal-WATCH program detailed here: www.cal-watch.org.
If you live outside of the Clearlake Oaks and Lower Arms, and you have an individual water system with a private intake that draws from Clear Lake, it is important to maintain awareness of current water quality conditions and assess your risk.
The most recent cyanotoxin monitoring data is available here: www.bvrancheria.com/clearlakecyanotoxins.
Exposure to drinking water contaminated with elevated concentrations of microcystin and cylindrospermopsin could cause liver and kidney damage.
The main source of human health effects data for microcystins is from acute recreational exposure to cyanobacteria blooms.
Symptoms include headache, sore throat, vomiting and nausea, stomach pain, dry cough, diarrhea, blistering around the mouth and pneumonia.
If you are concerned you have symptoms resulting from exposure to cyanotoxins, immediately contact your primary health care provider and call County of Lake Health Services at 707-263-1090.
The table below summarizes the health effects caused by the most common toxin-producing cyanobacteria.
“Clear Lake is a beautiful natural resource, and our community has many visitors who come to the area to experience it. Together, with care and consideration, we need to adapt to these changing times, and ensure residents and guests, alike, understand risks posed by cyanotoxins,” the county reported.
For additional information about cyanobacteria and harmful algal blooms, please visit the following websites.
Centers for Disease Control and Prevention: www.cdc.gov/habs/index.html
Environmental Protection Agency: www.epa.gov/cyanohabs
County of Lake cyanobacteria webpage: www.lakecountyca.gov/Government/Directory/WaterResources/ClearLake/Cyanobacteria.htm
Environmental Protection Agency’s 2015 microcystins report: www.epa.gov/cyanohabs/health-effects-cyanotoxins