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The original item was published from 9/19/2019 4:58:00 PM to 9/20/2019 9:19:56 AM.

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Recreation & Parks

Posted on: September 6, 2019

[ARCHIVED] Blue Green Algae

HP Blue Green Algae_news flash

Sonoma County Department of Health Services’ Environmental Health unit investigated the death of a dog suspected of being exposed to blue-green algae (BGA) after swimming at a pond in Rincon Valley Community Park on September 9, 2019.

Test results detected low levels of BGA toxins (Cylindrospermopsin and microcystin) in the pond water at Rincon Valley Community Park.

Based on this information and with communications with the treating veterinarian, BGA exposure was the most likely cause of death for the dog involved in the incident.

Additionally, test results showed low levels of the BGA toxins, (Cylindrospermopsin and microcystin) have been detected in Spring Lake Regional Park in Santa Rosa, which is operated by the County of Sonoma; and blooms of Blue Green Algae that are potentially toxic (though unconfirmed by testing) have been intermittently spotted near the dock and boat launch at the City of Santa Rosa's Lake Ralphine at Howarth Park. As a precaution, boating activities at Lake Ralphine have been canceled whenever these naturally occurring algae blooms are located in the area. 

Signage has been posted warning the public of the potential presence of BGA in bodies of water at Santa Rosa City parks, including at Rincon Valley Community Park, Lake Ralphine at Howarth Park, Fountain Grove Lake at Nagasawa Park, the holding pond at A Place to Play Park, Francis Nielsen Park. Signage has also been posted at Spring Lake Regional Park.

Swimming or dogs in the water not are allowed at any Santa Rosa City park and have not been allowed in the past.  

Blue Green Algae can be dangerous to people and pets, always follow these important safety guidelines:

  • No Swimming
  • Do not let children or pets go into or drink the water, or go near scum
  • Stay away from algae on shore, isolated side pools, and scum
  • Do not drink water or use for cooking. Boiling or filtering water will not make it safe
  • For fish caught in this water, throw away guts and clean with bottled water before cooking
  • Call your doctor or veterinarian if you or your pet get sick after going in the water

For more information about Blue Green Algae, please visit:

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