Long Beach Closes Beaches

Long Beach has closed three connected waterfront areas to swimming because of high bacteria levels, probably from human waste, and city health officials said Tuesday that the contamination will keep ocean water off-limits at least through today.

Marine Stadium and Mother’s Beach -- both popular sites for boaters and picnicking families, the latter featuring a waterfront playground -- were closed Friday after routine testing revealed unsafe levels of E. coli at Mother’s, said Dr. Darryl Sexton, the city’s health officer.

Colorado Lagoon has been closed for the same reason since Sept. 14, said Sexton, adding that the health risk at all three sites is limited to contact with the water.

The lagoon is the farthest inland and connected by a culvert to Marine Stadium, which is adjacent to Mother’s Beach.

Having all three closed at once, said Sexton, “really is unusual.”

By midday Tuesday, he said, investigations showed no sign of a spill or break in the storm drain systems of the city or of Los Angeles County. The storm drains can overflow into channels feeding into the sea, contaminating nearby beaches, but that usually happens during heavy rains.

Sexton said the original bacteria test at the lagoon indicated animal waste as the likely source of contamination. But testing at all three locations Friday indicated human waste as the source -- most likely from the holding tank of a boat or recreational vehicle driven into a beach parking lot, he said.

Because it does not receive adequate tidal flushing to churn out accumulated bacteria, the lagoon has had chronically high bacteria counts, although not always forcing closure. The lagoon also has a waterfront playground and picnic sites.

Officials in Los Angeles and Long Beach say preliminary investigations show no sign of a sewage system breakdown. The affected waterways are sheltered from the open ocean, and Sexton ruled out any large-scale dumping by a passing ship.

Along Long Beach’s seven miles of beach Tuesday, the affected areas were marked with warning signs, alerting the public to the health risk. When a beach fails to meet state standards for bacteria levels, ocean water contact should be avoided for at least 50 feet on either side of a sign, according to the city’s website, www.longbeach.gov.

The beach itself is not unsafe when such signs are posted, and the sand can be used for sunbathing or playing, health officials said. It is swimming or other contact with the bacteria-bearing ocean water that poses potential risk.

Ocean water is tested weekly year-round at beaches where swimming and other recreation are common, and monthly in other locations such as marinas. Once bacteria is found, water testing continues daily until safe levels of bacteria are restored for two full days.

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nancy.wride@latimes.com