A blue-green algae bloom. (Photo courtesy of California State Water Resources Control Board)

A buildup of blue-green algae (cyanobacteria), commonly called an algae bloom, along the Sacramento-San Joaquin River Delta has prompted a safety warning from Contra Costa Environmental Health Services.

The department is advising people who visit the Delta that contact with blooms can make people and pets very sick.

Cyanobacteria creates a green, blue-green, white or brown coloring on the surface of slow-moving waterways.

Advisory notices have been posted at the kayak launch and around the fishing dock at Big Break Regional Shoreline in Oakley after cyanobacteria was detected in the water.

It warns users to stay out of the water, and to not touch algae scum in the water or on the shore; not use the water for drinking, cleaning or cooking; not let pets or livestock enter or drink the water; and not to eat fish or shellfish from the water.

A caution advisory has also been posted near the boat ramp around the mouth of Mormon Slough by the California State Water Resources Control Board.

The water resources control board also found small amounts of cyanobacteria in water sampled at Fourteen-mile Slough/White Slough, Buckley Cove and the San Joaquin River at Windmill Beach. There may be other waterways that have unreported cyanobacteria, as well.

More information about harmful algae blooms is online at cchealth.org/eh/hab.