A mouthful of H2 ... uh-oh

SOUTHERN California beaches offer a little slice of heaven for true water hounds -- regular sets of big, muscular waves for surfers, cool ocean breezes for kite boarders and windsurfers and long stretches of shallow water for flopping around on rafts and belly boards.

But nearly everyone who’s ever swallowed a big mouthful of ocean water has wondered the same thing: What exactly is lurking in there -- and what are the chances of getting sick from it?

The answer depends on the water quality at any given beach at any given time. This year, despite last winter’s low rainfall, water quality at L.A. County beaches ranked among the worst in the state, brought down by particularly poor water quality in Long Beach, according to Mark Gold, executive director of the nonprofit environmental group Heal the Bay.

Heal the Bay issues a weekly “report card” for each beach, based on data assembled from more than 20 coastal health agencies.

The group’s 17th Annual Beach Report Card, released last week, found that although most California beaches (82%) had good to excellent water quality during dry weather, Los Angeles County beaches were below average on the whole, with Long Beach posting the worst dry-weather water quality in the state.

Poor quality water generally signals the presence of pathogens -- bacteria, viruses and parasites that wash down storm drains and creeks and descend on the ocean like rude, uninvited guests. The microscopic critters include the bacterias E. coli, salmonella and shigella; noroviruses, rotaviruses, coxsackievirus and hepatitis virus; as well as the parasites giardia and cryptosporidium.

Viruses can cause gastrointestinal distress, such as vomiting, diarrhea and cramping, as well as ear, nose and throat infections. Bacteria and parasites can also cause gastrointestinal illness.

Any disease that can be transmitted by the fecal-oral route could potentially be in the water, including 110 intestinal viruses, says Charles McGee, a microbiologist and lab supervisor for the Orange County Sanitation District.

In fact, when a beachgoer comes down with a waterborne bug, the most likely culprit is a virus, says Anne Anglim, an infectious disease specialist and assistant professor of medicine at USC.

Swimmers can pick up rashes and even staph infections from the ocean water, but Anglim believes that most water-related rashes are caused by the irritating effects of the salt.

The good news is that the chances of actually catching a bug from swimming at a Southern California beach is relatively small under normal circumstances, and most illnesses caused by ocean pathogens are generally mild, Anglim says.

In fact, the likelihood of contracting an illness is actually much higher in tropical waters, she says, where the warmer water provides a haven for pathogens.

Even swimming pools and water parks, with their warm, recycled water, pose greater risks of catching bugs like cryptosporidium, says Donna Ferguson, a microbiologist for the Southern California Coastal Water Research Project. “More outbreaks have been reported for swimming pools and other forms of treated-water recreation than natural water bodies,” she says.

Public health officials say that the odds of catching something is largely related to the “dose” of pathogens a swimmer receives. The more pathogens that are in the water and the more water that is swallowed or inhaled, the greater the chance of catching a bug.

Symptoms from water-related illnesses may not appear for several days after exposure. Consequently, it’s very difficult to determine how many people get sick each year from polluted water.

To protect the public from unwanted bugs, water samples at Los Angeles County beaches are tested weekly and sometimes daily for so-called “indicator bacteria” by the Los Angeles County Department of Public Health, the city Environmental Monitoring Division and the county Sanitation Districts. Long Beach’s coastal waters are tested weekly by that city’s Bureau of Environmental Health.

Indicator bacteria -- total coliform, fecal coliform and enterococcus signal the possible existence of pathogens. “If the number of bacteria exceed preset state standards for any one of those bacteria, we notify the lifeguards and they post a warning sign,” says Eric Edwards, chief of the water quality program for L.A. County’s Department of Public Health, Environmental Health. Long Beach has a similar system, says Nelson Kerr, a manager for the city’s Department of Health and Human Services Environmental Health Bureau.

Ironically, it’s the family-friendly enclosed beaches, which don’t have the constant flushing action of open beaches, that are generally the dirtiest.

Still, the biggest danger from a day at the beach probably isn’t in the water, says Ferguson. Everything from toddlers in diapers to poorly refrigerated picnic food can distribute pathogens.

Then there’s the biggest threat of all. “I’d be more concerned with going into the public restroom,” Ferguson says. “That scares me more.”

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janet.cromley@latimes.com

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Get beach-smart

* Before going to the beach, check water-quality websites, such as healthebay.org and L.A. County’s lapublichealth.org/phcommon/public/eh/rechlth/ehrecocdata.cfm.

* Upon arriving at the beach, take a good look around. Are there storm drains or creeks nearby? Steer clear of these pathogen superhighways.

* Does the water look clean? Sometimes pollution is visible.

* Rinse off after swimming.

* Wear goggles.

* Wear earplugs or dry ears thoroughly after swimming. Wet ears can create a warm home for a stew of pathogens.

* People with compromised immune systems may want to stick to the cleanest beaches.

* Stay out of the water for at least three days after a storm, and pay attention to closure signs.

-- Janet Cromley