For months, sanitation experts have puzzled over the discovery of sporadically heightened bacteria levels in ocean waters off Bolsa Chica State Beach.
They launched test after test, even flushing red dye down the toilets in the beach’s 14 restrooms to see if a leaking sewer system might be to blame.
Now the environmental mystery might be solved.
The suspected culprit is a 2.5-mile-long sewer line riddled with dozens of cracks, apparently allowing small amounts of liquid raw sewage to seep underground through the sand toward the ocean at one of Orange County’s most popular beaches.
The discovery has parks officials wondering if other area beaches might be vulnerable to leaks from their own sewer lines, and a review of state sewer systems may be in the offing.
Still, Bolsa Chica beach-goers are in no danger, report sanitation and health experts, who say they are concerned that people might stay away from the long stretch of sand and surf near Huntington Beach.
“Bolsa Chica is one of the cleanest and safest beaches in the county,” said Nancy J. Wheatley, director of technical services for the Orange County Sanitation Districts, who promised that “Bolsa Chica will be well monitored, and it will be safe this summer.”
The ultimate solution will be a new sewer line, with construction starting in the fall.
In the meantime, park overseers began a disinfection program over the Memorial Day weekend that in essence treats the leaking sewage with the same chemical used to clean swimming pools.
And to further protect swimmers and surfers, the park has begun a stepped-up water-monitoring program, collecting water samples five days a week at 13 spots along the 2-mile stretch of beach.
“Based on the scenario we have set up right now, there should be no undue alarm for that section of the coastline,” said Larry Honeybourne, water-quality chief at the Orange County Health Care Agency environmental health division.
The problem first surfaced in spring 1995 when routine testing by the sanitation agency--which tests coastal waters off much of Orange County--turned up slightly elevated levels of coliform bacteria in the waters off Bolsa Chica.
Most coliform bacteria is not harmful. But it is a red flag of sorts for health investigators, a “signal bacteria” that can indicate that disease-causing bacteria might be present.
The levels of bacteria found near Bolsa Chica were generally only a small fraction of the level--1,000 per 100 milliliters of water--that triggers a review to see whether a beach should be closed.
Still, the discovery prompted an exhaustive search for a source, culminating when a video camera inspection inside the sewer line pinpointed cracks and offset joints--at least 44 breaks found intermittently along the 2.5-mile stretch.
“It turns out the sewer system is in sort of a sad condition,” Wheatley said. Since the 20-year-old pipe is considered only middle-aged, some suspect the 1994 Northridge earthquake might have led to the cracking.
Now sanitation and parks officials are working together to make sure beach-goers are not affected.
Under the new disinfection program, calcium hypochlorite is dumped monthly into so-called “wet wells” where sewage is stored before being pumped along the sewer line. And large white tablets of bleach are regularly placed in baskets that are lowered into the wells.
Health officials are paying close attention to the water monitoring and will close a portion of the beach if necessary, Honeybourne said.
Dr. Gordon Labetz of the Huntington/Long Beach chapter of the Surfrider Foundation, an environmental group, said that while he is concerned about the problem, he is pleased with the Sanitation Districts’ response. However, he sounded a cautionary note.
“As far as we know, most of the time the water’s not polluted,” said Labetz, adding that while he would surf at Bolsa Chica this summer, he would keep his face out of the water.
But at the Sanitation Districts, Wheatley reports: “This is going to be one of the safest beaches this summer, because of all the attention it’s getting.”
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A cracked sewer line at Bolsa Chica State Beach is suspected of slowly releasing untreated sewage into the ocean. County sanitation officials say state beach bacteria levels are safe. But to insure health standards, ocean water is tested daily and bleach tablets are dropped into pump station “wet wells” to disinfect leakage until a new sewage line can be installed.
1. Fresh water, containing liquid sewage, leaks from cracked pipe.
2. Brackish ground water, seeping to ocean from Bolsa Chica wetlands, caries sewage top shore.
3. At shoreline, ground water percolates to surface, sporadically releasing small amounts of sewage into sea.
Source: Orange Coast Sanitation Districts; Researched by APRIL JACKSON / Los Angeles Times