"It's all geared toward changing the way we do beach monitoring," said John Griffith, a lead researcher in the study by the Southern California Coastal Water Research Project, as he drove the low-speed vehicle back to the trailer with his samples. "We want to give an answer the same day – and measure something that's relevant to public health." The study at Doheny, visited by some 1.8 million people a year, will be combined with a similar effort in Avalon on Santa Catalina Island off the California coast. In Orange County, Calif., ocean pollution trends have been on a mostly positive curve for years. Sewage spills continue to drop, the ones we have are smaller, and while bacterial spikes persist at places like Doheny and Huntington State Beach, Doheny's contamination has diminished in recent years, according to the Orange County Health Care Agency.
But bacterial warning signs still go up, and surfers still complain of earaches, sore throats and other infections. For many water-quality scientists, uncertainties have increased in recent years about just what is being tested – and how reliably the ocean water tests can flag traces of human sewage. "We've got to try to find something better," said Steve Weisberg, the research group's executive director. While scientists have been questioning swimmers and sampling ocean water for decades, the two rarely have been done together. In this study, while one group takes ocean samples, another, led by UC Berkeley, recruits beach visitors, sometimes entire families, for the second half of the project: tracking their swimming habits and illnesses over a period of weeks.
There are weaknesses in both methods of assessing the likelihood that a dip in the ocean will lead to the sickroom. Questionnaires and surveys might capture people who think they got sick from the ocean, but in reality, contracted their illness from food or one of the many other places where people cross paths with disease-causing microorganisms. On the other hand, contamination tests of ocean water typically take 24 hours to yield a result. That means people swimming in contaminated water often don't know it. And by the time the signs go up, the ocean might no longer be contaminated. By matching the water samples with interviews of beachgoers in real time, the scientists hope to get a far more precise picture of how the complex stew of microbes that wax and wane in the near-shore ocean affects the human bodies immersed in it.
Doheny is one of Southern California's most chronically contaminated beaches, but even there scientists can't always count on polluted water. Last year, they abandoned their first attempt to begin the study when dry weather and other factors kept Doheny's bacterial tests unusually clean. The samples prepared in the trailer are destined for a variety of universities and other institutions across the country, where scientists will use them to try out new ocean-water testing methods. "It looks pretty much like chaos, but everybody knows what they're doing," said Monica Mazur, a retired county water quality specialist, who volunteered to help prepare the samples. At least two critical scientific questions are driving these efforts. The first centers on the time lag between sampling and results, which meas many bacterial warnings are out of date before they are even publicly posted. Scientists at the University South Florida, the University of North Carolina, the U.S. Environmental Protection Agency and other institutionsare trying out new, faster testing methods that could yield results in a matter of hours. And instead of using bacterial flags to indicate the presence of sewage, they are measuring antibodies, DNA fragments and other bits of cellular machinery.
The second problem could cast into doubt the ocean-sampling methods that public health agencies nationwide have relied on for decades.
The most common tests measure types of bacteria that are normally harmless, but are thought to be present in a water sample whenever human sewage is there, too. These "bacterial indicators" act as proxies for disease-causing organisms. The problem is that these indicators – among them the most often-used bacterial species, enterococcus – might be shed by animals, or might be growing on their own in the environment, in rafts of dead algae and other places. Recent studies suggest that the bacteria used as sewage indicators could be thriving where no sewage at all is present. And if they are flushed out to sea, they can cause water sampling tests to give false alarms – prompting the posting of warning signs where a true threat of disease might not exist. That doesn't just ruin a day at the beach. It means city governments might be spending millions cleaning up creek mouths or stretches of beach that were never contaminated in the first place.
The only other recent Southern California study that combined water-quality testing with beachgoer interviews, in San Diego County's Mission Bay five years ago, showed almost no illness at all during times when counts of indicator bacteria were high. That suggests that the bacteria might, in some circumstances, be unreliable indicators of disease-causing organisms. For the Doheny researchers, even beachgoers who never set foot in the ocean are important. "We need a control group – people who don't go in the water," Griffith said. One of them, Mary Petersen, 76, of Santa Monica, Calif., took the time to answer a series of questions as she headed for home with her husband, Ken. Her reward: a free tote bag. Credit: OCRegsiter & Ben Pearson.
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