Our planet's beleaguered oceans have been making headlines all year, with gloomy reports on collapsing fisheries, invasive species, plastic pollution and more. But a less-publicized issue hits closer to home, especially as summer revelers flock to the beach in droves.
Put bluntly, the problem is poop. Fecal pollution--mainly from raw sewage--is contaminating large stretches of recreational water from the Gulf Coast to the Great Lakes.
Swimming in unsafe water can lead to sore throats and diarrhea, as well as more serious illnesses like meningitis and severe gastroenteritis. Recent research has shown that, after many years of decline, death rates from microbial gastrointestinal illness are on the rise. ¿Recreational exposures clearly play a role in causing these illnesses," says epidemiologist Rebecca Calderon of the U.S. Environmental Protection Agency.
Pollution caused more than 12,000 beach closings and advisories in 2002--the second highest number in 13 years--according to a study by the Natural Resources Defense Council. (The 2001 numbers were slightly higher, mostly because of drought conditions in 2002.) The continual rise in ¿no-swimming" days in part reflects better testing standards, the report notes, but scientists disagree over how to best monitor pollution and warn swimmers.
For years, the standard analysis has been based on coliforms--bacteria that give an estimate of the amount of feces in a sample. Most officials take one water sample a day and then post a warning sign on the beach when bacteria levels exceed a specified value.
¿It's a flawed system," observes Mark Sobsey, an environmental microbiologist at the University of North Carolina at Chapel Hill. Since bacteria must be grown, an analysis can take 24 hours or more. ¿We are still in this dilemma of making decisions about water that has already come and gone," he remarks.
To assist state and local officials with monitoring programs, the EPA introduced the Beaches Environmental Assessment and Coastal Health (BEACH) Act in October 2000. One goal of the BEACH Act was to spur development of ¿rapid indicators" to measure water quality on an almost continuous basis. ¿Obviously, people would like it to be done 10 seconds or less, but we thought that was pretty unrealistic," says Al Dufour of EPA's National Exposure Research Laboratory. ¿There was an arbitrary goal set up: We were going to attempt to measure water quality in two hours or less."
A number of new technologies that meet this standard are now being tested in various environments, and most experts agree they are a step in the right direction. But recent research suggests that rapid indicators might not be a panacea.
Stanley Grant of the University of California at Irvine has analyzed warning errors at Huntington Beach, Calif. His findings, published the May 1 issue of Environmental Science & Technology, suggest that even if sample turnaround were almost instantaneous, error rates in beach warnings would still be quite high. Grant's work points to a more fundamental problem: the current ¿binary" advisory scheme--wherein a warning sign is either posted or not, giving the public no further information--is intrinsically error prone, he asserts. He recommends switching to an ¿analog" system, similar to the one used to issue ozone warnings in urban areas, assigning a letter grade to beaches from "A" to "F."
Other researchers maintain faith in rapid indicators. Stephen Weisberg, executive director of the Southern California Coastal Water Research Project, agrees with Grant that if officials are taking only one sample each day, then decreasing sampling time will do little good. ¿But if you sample once in the morning, then get the results right away and find out you have a high level, you can sample again five times in different places before noon," he counters. Weisberg and Sobsey were among the experts on the committee for a recent National Research Council (NRC) report that addressed indicators of waterborne disease. The report stressed the importance of rapid indicators but placed them in the context of a three-phase approach to monitoring beaches.