Highly toxic harmful algal bloom at Lake Elsinore triggers “Danger” advisory to avoid water contact
Lake Elsinore – Testing in five distinct areas of Lake Elsinore indicates the presence of a harmful algal bloom with high levels of toxins that pose a significant health threat to humans and pets, prompting a “Danger” advisory urging visitors to avoid water contact of any kind and not to not eat any fish or shellfish from the lake.
The State Water Resources Control Board, in conjunction with the Santa Ana Regional Water Quality Control Board and City of Lake Elsinore, urges the public to stay out of the water, including refraining from boating and paddle boarding, at Lake Elsinore in Riverside County. Signs have been posted with a recreational advisory of “DANGER” to alert visitors of the elevated risk. All visitors to Lake Elsinore are urged to follow posted guidance until further notice.
The City of Lake Elsinore has been testing regularly for HABs at Lake Elsinore, which is particularly vulnerable to HABs outbreaks due to its shallow waters, increasing temperatures, and its history of blooms in the summer months, as chronicled in its “Lake Watch” program. The bloom currently occurring in the lake appears suspended on the water’s surface (picture attached). Most recent sampling results indicate that the lake contains extremely elevated levels of toxins associated with cyanobacteria, a group of organisms that form harmful algal blooms and can produce potent toxins.
While a “Danger” advisory is triggered at 20 micrograms per liter of microcystins, the latest results from testing in Lake Elsinore show the presence of up to 36,750 micrograms per liter.
A “DANGER” advisory means:
- Stay out of the water, including watercraft.
- Do not let pets and other animals drink or go into the water or go near the scum.
- Stay away from scum, and cloudy or discolored water.
- Do not eat fish or shellfish from this water.
- Do not use this water for drinking or cooking. Boiling or filtering will not make the water safe.
HABs are associated with health risks, as they produce dermatoxins that can cause itchy skin and rashes, as well as gastrointestinal distress, headaches, agitation and weakness, or even abnormal breathing if HAB material is swallowed while swimming. Dogs and children are most susceptible to exposure because of their smaller body size, increased potential to swallow water while swimming, and tendency to stay in the water longer. Anyone who suspects exposure to HABs should wash themselves, their children and/or dog immediately.
Due to the size and toxicity of this bloom along with the summer heat and absence of rainfall this time of year, the bloom may proliferate and alter its potential to produce toxins. Bloom conditions can change rapidly, as wind and waves move or concentrate the bloom into different regions of the lake. In some areas, the bloom may concentrate and form a film or scum on the water surface. The color of the water may also appear discolored as bright or dark green and brown.
The City of Lake Elsinore has posted advisory signs to notify visitors of the bloom. The city and the Water Boards will provide regular updates to inform the community when postings are removed on the California HAB Reports Web Map and the Lake Watch webpage.
The Water Boards recommend that people practice healthy water habits while enjoying the outdoors this summer at California’s lakes, rivers and streams:
- Check the California HAB Reports Web Map to see if HABs have been reported in your area.
- Heed all instructions on posted advisories if present.
- Avoid algae and scum in the water and on the shore.
- If you think a harmful algal bloom or toxic algal mats are present, do not let pets and other animals go into or drink the water or eat scum/algal mats on the shore.
- Don’t drink the water or use it for cooking.
- Wash yourself, your family and your pets with clean water after water play.
- If you catch fish, throw away guts and clean fillets with tap water or bottled water before cooking.
- Avoid eating shellfish if you think a harmful algal bloom is present.
Obtain medical treatment immediately if you think that you, your pet, or livestock has gotten sick after going in the water. Be sure to alert the medical professional to the possible contact with cyanobacteria. Also, make sure to contact the local county public health department.
To report a bloom, do one of the following:
Fill out the Bloom Report form on the HABs Portal:
Email: CyanoHAB.reports@waterboards.ca.gov
Call the HABs hotline: 1-844-729-6466 (toll free)
Contact your County Public Health Office
