Officials offer advice on staying healthy while recreating in lakes, rivers, streams, creeks, and reservoirs
LAKEPORT, CA – With warm weather in the forecast and recreational water sports gearing up for the summer, health and water resource officials across the state are reminding the public to be mindful of harmful algal blooms (HAB) in lakes, rivers, streams, creeks, and reservoirs, and to keep children and pets away from these HABs if they see one.
HABs are the result of a type of bacterium, known as cyanobacteria. These microscopic organisms are an essential part of the environment and have existed for millions of years. Typically, they live in balance with other living creatures. When environmental conditions favor their growth, they can proliferate and accumulate in numbers that are sometimes visible to the naked eye, creating what is referred to as a HAB. Some cyanobacteria are capable of producing toxins that can harm pets or people that come into contact with them. Exposure can occur through direct skin contact, ingestion (eating or drinking), or breathing aerosols of affected water.
HABs occur in water bodies throughout the world. They can be recognized by several features, such as an oily or paint-like sheen on the water’s surface, floating mats, or a “pea soup” appearance of the water. There may be cyanotoxins in the water even if you do not see the description listed above. HABs have been reported in Lake County in prior years, such as this one photographed last year from Monitor Point in the City of Clearlake. Although HABs can occur anywhere in a body of water, in lakes they tend to be more concentrated in areas where water movement is limited and is downstream of wind and water currents. In rivers or creeks, they can be found attached to the sediment on the bottom, floating along the shoreline, or in backwater eddies.
It is important to distinguish cyanobacteria (also known as “Blue-Green Algae”) from green algae and water plants that are not thought to pose potential hazards to health. The State has created a visual guide with photos to help users recognize HABs and differentiate them from green algae or water plant growth. The guide is available online at:
Direct exposure to a HAB, if it is toxin-producing, can result in eye irritation, skin rash, mouth ulcers, vomiting, diarrhea, or cold and flu-like symptoms. Pets can be especially susceptible because they tend to eat the cyanobacteria mats, drink while in the water and lick their fur after, increasing their risk of exposure and illness.
This year, monitoring of water from shoreline sites and around Clear Lake is again being conducted by the Big Valley Rancheria and Elem Indian Colony. Toxin reports are available online at: www.bvrancheria.com/clearlakecyanotoxins.
The California Water Boards have collaborated with the Bloom Watch App, which allows anyone observing a potential HAB to document it and send information to water managers. In using the app, each user will be asked to answer a few basic questions and provide pictures of the potential HAB. The public can also report the bloom directly to the California Water Boards by calling their free HAB Hotline 1-(844) 729-6466 or report the bloom through their online HAB Portal.
The Statewide Guidance on Cyanobacteria and Harmful Algal Blooms recommends the following for waters impacted by harmful cyanobacteria:
• Keep pets and other animals out of the HAB-affected water. Do not allow them to drink the water or eat algal material (scum) on shore. If they do get in the water, do not let them drink the water, swim through algal material, scums or mats, or lick their fur after going in. Rinse pets in clean water to remove algal material and potential toxins from fur.
• Do not drink, cook, or wash dishes with untreated water directly from the lake. Common water purification techniques such as camping filters, tablets, and boiling do not remove toxins.
• People should not eat mussels or other bivalves collected from HAB-affected areas. If fish are consumed, remove the guts and liver, and rinse filets in clean drinking water.
• Get medical treatment immediately if you think that you, your family, your pet, or livestock has gotten sick after going in the water. Be sure to alert the medical professional to the possible contact with HABs. Also, make sure to contact Lake County Health Services Department, Public Health Division at (707) 263-1090.
Remember to always practice healthy water habits:
• Pay careful attention to all instructions on posted advisory signs.
• Avoid body contact with HABs.
• Keep an eye on children and pets, ensuring that they do not approach areas with HABs growth.
• Do not drink untreated lake, river, and creek water. Common water purification techniques such as camping filters, tablets, and boiling do not remove toxins.
• Do not cook or wash dishes with untreated water directly from the lake, river, and creek.
• Wash yourself, your family, and your pets with clean water after lake, river, and creek play.
• Consume fish only after the guts and liver have been removed. Rinse filets.
For more information, please visit:
California Harmful Algal Blooms Portal
Current Toxin Levels Clearlake, Big Valley Rancheria and Elem Indian Colony
California Cyanobacteria and Harmful Algal Bloom (CCHAB) Network
California Surface Water Ambient Monitoring Program Freshwater HAB webpage
California Department of Public Health
U.S. Environmental Protection Agency–CyanoHAB website