Dangerous toxins found in Discovery Bay, health officials say stay out of water

DISCOVERY BAY, Calif. - It's hot. It's summer. And for people like Lisa Black and her daughter, there's nothing like a jump in a lake.

 "We have a water trampoline and just play in the water," she said. 

But Contra Costa Health Services’ environmental health departments this week alerted the public about toxic blue-green algae found in parts of Discovery Bay, warning that people and pets should stay out of the water.

On June 27, the County Environmental Health Department took water samples from 12 locations in Discovery Bay, and all tested positive for microcystin, a harmful toxin released by blue-green algae.

Results also showed that 75 percent of the samples were above the caution level. Officials posted a public notice on Thursday. 

Microcystin is a liver toxin that can cause an array of ailments, including rashes, eye irritation, diarrhea, stomach cramps, vomiting, fever and a sore throat, according to the California Department of Health.

Exposure to high levels can lead to serious illnesses and even death, public health officials say.  People should not eat fish from Discovery Bay but the tap water is safe.

"Humans are at risk for rashes, respiratory issues. Some GI issues," said Joe Doser with Contra Costa Environmental Health. 

But that's not stopping some residents like Jayce Bough. "Ive been out here the last couple of years and it hasn't gotten me yet," he said. 

In other areas, East Bay Regional Park District officials found similar toxic blue-green algae on July 13 at Oakley’s Big Break Regional Shoreline kayak launch and around the fishing dock where warning signs are now posted. Swimming is never permitted here, but boating, kayaking and fishing are OK despite the presence of the algae.

Blue-gree algae was found at Lake Anza in Berkeley and Quarry Lakes in Fremont. But toxins weren't detected and these areas are open for swimming. 

Lake Temescal in Oakland has been closed for the last several summers because of the same issue. But this year, the lake is open and there has been no toxic algae has been reported so far this summer.

Toxic algae blooms, or cynobacteria, is an issue that’s plaguing water bodies across the country. The biggest reasons? Toxic blooms are a worldwide problem and are exacerbated by sediment and nutrient build-up, pollution and aging reservoirs, along with warm temperatures because of drought and global warming.

FOR MORE INFOMATION: For updates, explanations of posted advisories, a map of sampling sites and other information in Contra Costa County, visit here. For algae updates in the East Bay Regional Park District, click here. For information on harmful algae bloom incidents in California, visit here.