Contra Costa health officials and the Central Valley Regional Water Quality Control Board advise people and pets in the Discovery Bay community to avoid contact with local bodies of water because of blue-green algae blooms.

Contra Costa Health Services Environmental Health Division (CCEH) received results this week for several water samples taken in late June from the southwestern section of Discovery Bay. Results found elevated levels of a natural toxin produced by blue-green algae blooms.

“We are advising residents to stay out of the water and keep their pets out of the water in the southwestern portion of Discovery Bay,” said CCEH Director, Dr. Marilyn C Underwood, “However, water circulates throughout the community, so the algae can also move and spread and therefore it is prudent to be cautious and to stay out of the water if you see scum or algae blooms.”

Exposure to the toxin can cause rashes, skin and eye irritation, allergic reactions, gastrointestinal upset and other symptoms.

“It’s important to know that dogs are especially vulnerable to getting sick from this toxin. There have been reports from past incidents of dogs dying after drinking the water or licking algae from their fur after swimming in water with blue-green algae blooms.  If your pet gets ill after swimming in water with an algae bloom, take them to the vet immediately,” said Christine Joab, Cyanobacteria Coordinator for the Central Valley Water Board.

For a fact sheet to help veterinarians diagnose illness related blue-green algae exposure, visit www.mywaterquality.ca.gov/habs/what/vet_habs_factsheet.pdf

Blooms of blue-green algae, also known as cyanobacteria, can look like green, blue-green, white or brown foam or scum floating on top of water, or suspended in the water. Warm water temperatures and nutrients contribute to blooms, but these will eventually subside under cooler conditions.

CCEH will regularly test bodies of water throughout Discovery Bay and update the community while these conditions persist.

“Anyone who had contact with blue-green algae and has now developed symptoms or believes they may have consumed contaminated water should contact their healthcare provider immediately or call California Poison Control at 1-800-222-1222,” said Underwood.

No illnesses linked to Discovery Bay algae blooms have been reported in 2017. A child became sick after swimming in Discovery Bay during a similar event in 2016. Only recreational water areas are affected. Tap water in Discovery Bay is unaffected by the algal bloom.

FAQs

Is it safe for me to go in the water in Discovery Bay?

It depends where you are and if there are advisories posted in the area.

A CAUTION sign means:

Do not swim or wade near algae or scum

Keep your children away from algae in the water or on the shore

Do not drink the water or use it for cooking

Do not let pets or livestock go into or drink the water or eat scum on the shoreline

Do not eat shellfish from the water

A WARNING sign means:

No swimming

Stay away from scum, and cloudy or discolored water

Do not use these waters for drinking or cooking

Do not let pets or livestock go into or drink the water, or go near the scum

Do not eat shellfish from these waters

For fish caught here, throw away guts and clean fillets with tap water or bottled water before cooking

A DANGER sign means:

Stay out of the water until further notice. Do not touch scum in the water or on shore.

Do not let pets or livestock drink or go into the water or go near the scum

Do not eat fish or shellfish from these waters

Do not use the water for drinking or cooking. Boiling or filtering will not make the water safe.

Exposure to blue-green algae can cause rashes, skin and eye irritation, allergic reactions, gastrointestinal upset, and other effects. At high levels, exposure can result in serious illness or death, according to the California Department of Public Health.

What about my pets?

Keep pets out of water with blue-green algae blooms. Dogs are especially vulnerable to getting sick and there have been reports through the years of dogs dying following exposure associated with drinking the water and licking algae from their fur after wading/swimming in water with blue-green algae blooms.

Is there an issue with drinking water?

No, contamination only affects recreational water areas, not drinking water from the tap in Discovery Bay.

Who should I contact if I swam in the water and now have symptoms?

If you think you or someone else is displaying symptoms of blue-green algae poisoning, contact your health care provider or the California Poison Center Help Hotline at 1-800-222-1222.

What can I do to get rid of blue-green algae in Discovery Bay?

We do not recommend attempting to treat or remove the algae. Blue-green algae blooms are natural to the environment’s food chain, and eventually dissipate on their own. Chemical treatment is often ineffective and can result in more toxins being released into the water as algae cells die, as well as unintended effects on other species in the area.

Algae blooms result from changes in water conditions that encourage sudden growth of the species. The best way to reduce and prevent blooms is to reduce water pollution, particularly from runoff containing fertilizers or pesticides. Pick up trash dumped in waterways, and make sure all household sewer systems are working properly.

Treating aquariums with a hydrogen peroxide solution is a common way to get rid of some kinds of algae. But the Delta is not a closed system like an aquarium, so the results would be unpredictable, both in terms of efficacy and impact on the environment.

For updates, detailed explanations of posted advisories, a map of sampling sites and other information, visit cchealth.org/eh/blue-green-algae.