Pre-holiday assessment for harmful algal blooms: mostly good news, but conditions will change

With Memorial Day weekend nearly here, the State Water Resources Control Board wants Californians to be aware of the potential for harmful algal blooms in lakes and streams and understand how to keep children and pets from getting sick.

Because of the greater frequency of HABs during the summer months, the State Water Board recently performed pre-holiday assessments at some of the most popular water bodies across the state.

The board’s HAB webmap has been updated with the latest information so those engaging in water recreation can make informed choices to keep loved ones safe.

The board collected samples from 65 waterbodies, with lab results triggering a danger advisory at Lake Hemet and caution advisories at a few other Southern California waterbodies. With temperatures rising throughout the summer, there is the potential for more HABs containing greater toxicity.

Freshwater HABs can cause illness and be especially harmful to children and pets.

To learn how to stay safe, report a bloom, and track multiple blooms statewide, the public can access the board’s web portal. HABs can be a variety of colors – green, white, red or brown – and often have the appearance of thick paint or small flakes floating on the water. Cyanobacteria can also grow as mats attached to rocks, sand or other plants at the bottom of a water body. These mats sometimes float to the surface and wind up along shorelines.

The public can safely enjoy the outdoors this summer by practicing these healthy water habits  

  • Heed instructions on posted advisories if present.
  • Avoid algae and scum in the water and on the shore.
  • If it appears that a harmful algal bloom is present, do not let pets and other animals drink the water or eat scum/algal accumulations on the shore.
  • Don’t drink or use untreated water for cooking.
  • Wash yourself 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.

Because cyanobacteria can produce toxins, they have the potential to harm the environment, people, pets, wildlife or livestock. Dogs and children are most likely to be affected because of their smaller body size, increased potential to swallow water while swimming, and tendency to stay in the water longer. Recreational exposure to cyanobacteria and associated toxins can cause eye irritation, skin rash, vomiting, diarrhea and cold and flu-like symptoms.

Dogs are especially susceptible because they tend to drink while in the water and lick their fur afterward, increasing their risk of exposure and illness. Symptoms with animals include vomiting or diarrhea, lethargy, abnormal liver function test results, difficulty breathing, foaming at the mouth, muscle twitching, and sometimes death. The Office of Environmental Health and Hazard Assessment has a fact sheet to help inform dog owners.

The public should get medical treatment immediately if they believe that they, their pets or livestock have gotten sick after going in the water and alert the medical professional to the possible contact with cyanobacteria. Also, they should make sure to contact the local county public health department.

To report a bloom or a potentially related human or animal illness

For more information about HABs, visit the California Harmful Algal Blooms Portal.