High tide for beach closings
New research helps better pinpoint causes of water pollution at US beaches.
(Page 2 of 2)
Five years ago, a combination of such factors hit Huntington Beach, one of America's most popular and surfable beaches. Clean for years, the Orange County, Calif., beach was closed much of that summer by bad water. Area businesses lost millions of dollars and beachgoers complained bitterly, sparking a search for answers.Skip to next paragraph
Subscribe Today to the Monitor
That meant putting Ken Theisen, one of a growing number of beach-water sleuths, on the case. An environmental scientist for the Santa Ana region of the California Regional Water Quality Control Board, he tracked down sewage and other pollution, sending TV cameras into sewers to spot leaky pipes that municipalities could then patch. In all, he identified 2.5 million gallons of daily runoff full of fertilizer and pet waste, along the eight-mile beach, that has since been diverted to sewage treatment.
Last year, for the first time in several years, Huntington was not ranked among the state's Top 10 "beach bummers," as rated by Heal the Bay. Yet Dr. Theisen is flummoxed by a four-mile stretch rated only a "C" by Heal the Bay.
"We've reduced pollutants on this beach by 90 percent since 1999 ... and still we've got a problem," he says. "There are times where, yes, I've pulled my hair out wondering what the heck can this be?" During low tides each month, the beach is often inexplicably inundated with bacteria and must be closed - although there is no apparent source for the sewage pollution.
It's part of a nationwide mystery. The NRDC survey found that "unknown sources" were responsible for 62 percent of the beach closings and advisories in 2002. By contrast, polluted runoff caused 29 percent.
Enter another scientific sleuth, Alexandria Boehm, an avid surfer and relentless research scientist. At one point in her zeal to solve the Huntington mystery, she even tasted suspect groundwater to search for clues.
"Yeah, it was risky, but sometimes we've got to have fun," says the Stanford University environmental engineer. "It was a dare by some of my students. Actually, it tasted really sweet."
After spending July evenings in the Huntington surf collecting 11 tons of water from different depths, she and colleagues began to unravel the mystery. In a paper published in May in an academic journal, the group pointed to the possibility that contaminated groundwater beneath the beach could be the culprit. High in nitrates, which could support bacteria growth, it was being sucked through the sand and into the surf zone by low tides that created a kind of hydrologic pump.
Theisen and others say they aren't convinced that low-tide groundwater flow is the culprit. Most testing of groundwater under the beach hasn't shown high bacteria counts, he says.
But others contend Dr. Boehm's findings may help explain otherwise inexplicably polluted water. "On the Outer Banks [of North Carolina], we have these multimillion dollar houses near beaches, many of them on septic systems," says Rachel Noble, marine biologist at the University of North Carolina at Chapel Hill. "You could have a situation where groundwater is leached out through the sand at a beach through the tidal cycle." She is working to develop biological tracers of contaminants.
Such research is encouraging to Stephen Leatherman, director of the laboratory for coastal research at Florida International University in Miami. He's established the National Healthy Beaches Campaign, a three-year-old project about to release the names of 80 beaches that his group can "certify" as "healthy beaches." "Dr. Beach," as students sometimes call him, has traveled to more than 1,000 US beaches and many abroad.
Despite his concerns about overdevelopment, he says US beaches still are among the cleanest he's seen in the world.
He recalls a resort on an island off the coast of Thailand. One of the hotel rules, he says, restricted guests from flushing toilet paper. Finding that odd, he traced the sewage lagoon out back to a river that wound its way to the ocean. The reason for the antiflush rule, he speculates, was that it would wash back onto the beach - a visible indicator of otherwise hidden pollution. "It looked like a beautiful tropical paradise. But that stuff was going straight out into the water. I didn't go swimming."