The county posted signs this week warning swimmers to avoid beach areas near five county storm drains--including four in Santa Monica and one in Redondo Beach--where coliform bacteria is being discharged onto the sand and into the beach-line surf.
Coliform, a common bacteria found in soil and in animal and human feces, has been detected at high levels in the surf or on the beach where storm drains spill onto Santa Monica beach at Chautauqua Avenue, Santa Monica Pier, Pico Avenue-Kenter Avenue and Ashland Avenue. A storm drain at the end of Avenue I in Redondo Beach is also contaminated.
Jack Petralia, chief of sanitation for the county's recreational swimming division, said most of the coliform bacteria found by the county is not harmful and comes from natural sources such as soil runoff.
Possible Disease Indicator
However, he said about 10% of the coliform was fecal coliform, coming from animal droppings or humans. Fecal coliform does not cause disease in humans but is used by the county as an indicator that other disease-causing viruses or bacteria from feces could be present, he said.
"If we'd found fecal coliform making up more than one-third of the bacteria, we'd be concerned, but at this ratio it is not a health worry," he said. "The signs are just a precaution."
State standards say that more than 1,000 coliform organisms per 100 milliliters of water can, under some circumstances, pose a threat to human health.
Petralia said that at four drains, the coliform readings were so high that they went beyond the county's measuring instruments, which detect up to 24,000 coliform organisms per 100 milliliters of water. The Chautauqua Avenue drain had fewer than the rest, with 9,200 per 100 milliliters.
May Be Swimming Hazard
Although the county has stressed that the high coliform counts were made up mostly of non-fecal coliform and are not a health hazard, some environmentalists say hazards may be present.
Ellen Stern Harris, president of the Fund for the Environment, which is involved in Santa Monica Bay pollution issues, said no studies have been conducted in California to determine whether swimmers get sick from storm-drain runoff.
She cited an often-quoted 1982 study by Johns Hopkins University, which found that swimmers were getting sick "from even marginally polluted water."
Her concerns were echoed by Dr. John Skinner, an Orange County internist who has fought for increased treatment of sewage dumped off the coast.
"People who get sick from swimming in water polluted by human waste don't know that's what made them sick," Skinner said. "You go back and you wonder, 'Is it the hamburger I ate?' You don't think of swimming."