Picture the solitary surfer on the perfect wave.
Not really. A host of nasty creatures too small to be seen share that water.
The next time you plan a cooling splash in the ocean, a dip at a lake or a swim at an indoor pool with water slides and fountains, remember you could have company that leaves you with a medical memento of your visit.
On the other hand, the rate at which occasional beachgoers and other bathers get sick from water they inhale or swallow is probably fairly low, although no one has gotten a handle on the precise rate. The risk rises with exposure.
Surfers--those inveterate water lovers--are continuously exposed to the microscopic zoo that thrives in the sea. Despite warnings to stay out of the water for 72 hours after a storm, surfers usually take their chances when waves are churning brown and murky with urban runoff.
"If you're on the beach and you see perfect barrels firing offshore, it can be the color of cappuccino and you're going to put on your wetsuit and go," says Steve Hawk of San Clemente, a writer and former editor of Surfer magazine. Ask him about skin problems and other waterborne illnesses and he responds: "I've had them all."
Water supports not only native marine creatures, but other invaders that wend their way there, invisibly carried by people or pets who take a plunge.
If you could peer into a drop of water where people are at play, you might find tiny round or rod-shaped bacteria that make their usual home in the guts of humans and animals. Or tiny, roundish viruses from human waste. That drop could also contain weakened forms of polio excreted by people who have just been vaccinated. And perhaps tiny plants called phytoplankton in toxic red tides that may trigger reactions in swimmers, fishermen or passersby on piers who inhale sea spray. Health officials post signs and close beaches when tests show that levels of biologic pollutants are unsafe. They monitor total coliform--a group of bacteria that come from soil, plants, animals and humans--as well as fecal coliform, most of which is the common gut-dweller e. coli, along with the ball-shaped enterococci, another intestinal bug that often enters the ocean through storm drains. These three "indicator" bacteria don't often produce illness, but at sufficient concentrations they can indicate the presence of other microorganisms that can make you sick.
"Any time you see water flowing across the beach, you shouldn't swim in it or within 50 yards of that area upcoast or downcoast. If you see a storm drain that's flowing, you shouldn't swim next to it," says Charles McGee, microbiology laboratory supervisor for the Orange County Sanitation District. The agency monitors 17 miles of coastline in Orange County from Memorial Day through Labor Day. On July 1, health officials closed a mile of Huntington State Beach because of high bacteria; they have been searching for a suspected sewage source.
Lakes and dams are other potential trouble spots for illnesses spread by people who use recreational waters as toilets.
Even indoor pools, where you might expect chlorination to annihilate anything dangerous, can pose a threat to lifeguards who sit about 8 feet above the surface. Bacteria killed by the chemicals hover in sprays and can hitch a ride deep into the lungs with every breath, triggering inflammation and scarring. Indoor and outdoor pools pose a more general hazard to swimmers when chlorine isn't sufficient to kill microorganisms.
Pathogens Collect Near the Water's Surface
So choose your wet playgrounds carefully.
Some of the biggest concentrations of bacteria and viruses are 1 to 2 feet below the surface of the water, where some people "slyly and unbeknownst to their swimming partners" are relieving themselves or coughing up material that finds "little tidal recesses where it sort of collects, as flotsam and jetsam will do," says Dr. Mark Renneker of San Francisco, founder of the Surfer's Medical Association.
Renneker suspects these bacteria are responsible for more cases of illness than environmental scientists and doctors ever hear about. He hypothesizes that bacteria and viruses are causing "subclinical" infections, which may make someone feel slightly sick, but not bad enough to seek care.
Jed Alan Fuhrman, a marine biology professor at USC, looks at the viruses--called enteroviruses--that can cause intestinal and neurological symptoms. They include hepatitis, which causes liver infection; coxsackie, which can cause an inflammation of the membrane around the brain called meningitis; and rotavirus, which is responsible for severe diarrhea. He tests water at piers and where storm drains empty to see if viral concentrations are sufficient to be detected. Researchers know little about those viruses other than that they can "live longer in water than bacteria and can cause symptoms at lower densities than bacterial densities."
Heal the Bay, a not-for-profit coastal advocacy group in Santa Monica, this year began offering a weekly report card to help beachgoers judge which waters might be unhealthy. The report card, posted on the Internet (http://www.healthebay.org) grades water quality at 250 locations from the Orange-San Diego County line to the Santa Barbara County line near San Luis Obispo.
It Pays to Monitor Water Safety Reports
Some beach-lovers are aware that a day at the shore might be followed by a day in bed with an upset stomach, and they choose their spots accordingly.
Brian LaRuffa, manager of Harbor Surf Shop in Seal Beach, is one such person. He's suffered irritated, burning eyes and an intestinal infection called gastroenteritis after surfing polluted waters off jetties at the mouths of the Santa Ana River at Newport Beach and the San Gabriel River at Seal Beach. After a decade of surfing almost daily, he's become more cautious.
LaRuffa favors surfing Huntington Beach or other parts of Newport Beach instead of the waves behind his shop: "I won't go out here, just because of pollution. I can't afford to get sick. It isn't worth it to me."
Despite a decade of monitoring and efforts to clean up the water, Mark Gold, Heal the Bay's executive director, laments the fact that "a day at the beach probably poses as much of a health risk as it did 10 years ago."
However, he says, the risk of a major sewage spill occurring during dry weather is much lower because of improvements in sewage treatment plants and sewage systems.
The worst problems come when swimmers venture close to storm drains, according to a study Gold co-authored that appears in the July issue of the journal Epidemiology. The work, led by USC epidemiologist Robert Haile, is based on a 1995 survey of thousands of swimmers at three Santa Monica beaches who dunked their heads while swimming. Those who swam near storm drains were twice as likely to suffer gastrointestinal and respiratory problems, fever and sore throats as those who kept at least 400 yards away.
The study also found:
* Bacterial counts were higher at ankle depth than at chest depth, which means children who play in the shallows are at higher risk.
* High bacterial counts occurring as much as 100 yards from a flowing storm drain, and sometimes even farther.
* Intestinal viruses existing in almost every storm drain the researchers sampled, even though storm drains are separate from sewage systems.
Freshwater and Pools Can Also be Hazardous
Jack Petralia, director of environmental protection in the Los Angeles County Department of Health Services, also monitors three freshwater swim areas: Castaic Lake in Castaic, Santa Fe Dam in Irwindale and Puddingstone Lake in San Dimas.
"We've had more trouble with illness in freshwater bathing [areas] because we get so many people in them. You put 1,000 people in a small body of water with no chlorination, and if somebody is sick in there and has diarrhea, they can get everybody around them sick."
During the 1985 Labor Day weekend, 68 people became ill with shigellosis, a form of dysentery, contracted while bathing at Santa Fe Dam, but there hasn't been a similar outbreak since then.
For the last few years, L.A. County has pumped chlorine solution underneath the sand at the three freshwater swim areas on weekends. There have been no major reports of illness since the program began.
Petralia says public swimming pools generally are safe, except when someone loses bowel control in the water. In that case, county authorities request the pool close for 24 to 48 hours. As a rule, Petralia advises that if pool water is cloudy, "don't go in."
Indoor swimming pools with waterfalls, slides, sprays and spouts pose a health hazard that has become known as "lifeguard lung" since it was first identified in 1989.
Dr. Cecile Rose, an associate professor of medicine at National Jewish Medical and Research Center in Denver, coined the phrase after finding inflamed nodules in the lungs of career lifeguards at a municipal pool.
The first patient was a competitive bicyclist who "had gone from winning races to losing races." The granulomatous pneumonitis in his lungs was comparable to "farmer's lung," found in farmers exposed to moldy hay. Rose found the disorder in other young, otherwise fit lifeguards who had been diagnosed with asthma, flu, mononucleosis, even anxiety or malingering.
The pool where they all worked had fountains and other features that produced an aerosol rich with bacteria killed by the chlorine. The more the lifeguards breathed in this mixture, the more their likelihood of developing the immune reaction. An ozone-based disinfection system installed at the pool has prevented recurrences, although Rose has seen similar cases of pneumonitis in hot tub users.
So far, she says the "preponderance of evidence" indicates outdoor pools aren't a problem because the aerosols are diluted quickly by the air.
Despite the plethora of pathogens in untreated coastal waters, Renneker says there are relatively few outbreaks of disease at the ocean, which he attributes to generally high standards of water treatment and low rates of many diseases in this country.
As for that lone surfer, well, Renneker predicts that as coastal science blossoms, experts will identify a host of microbes that cause disease--and perhaps discover at the same time that surfers and others who are exposed regularly "actually develop a kind of immunity" that lets them feel as though they are alone riding those California waves.
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Hazards in a Drop of Water
High concentrations of bacteria such as enterococci and fecal coliform, viruses from human waste, and the phytoplankton that cause "red tide" may pose health risks for swimmers and surfers.
Areas of high risk:
* Near storm drains or river outlets
* In shallower water (ankle deep)
* In high-use freshwater bathing areas
* Where pool water is cloudy