The findings are reported in the Aug. 14 Web edition of Environmental Science and Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society.
Using a 43-year history of data and several high-frequency sampling surveys, the researchers studied the surf water quality at Huntington Beach, Calif., immortalized as "Surf City" in the 1960s hit song by the group Jan and Dean. The beach made national headlines in the summer of 1999 when a large section was closed to the public, hurting the local economy and drawing attention to beach water quality around the country.
The researchers found that coastal water quality is controlled by an intricate relationship among a number of physical and biological factors, such as tidal cycles, seasonal rainfall and El Nino events. This complexity makes beach water monitoring difficult, and it raises questions about existing monitoring programs across the country.
A July report by the National Resources Defense Council found that there were 19 percent more beach closures and advisories in 2001 than in the previous year, which the group attributed to increased monitoring and better testing standards for bacteria and other pathogens.
Most of the closings were triggered by a single "grab" sample, according to Stanley Grant, Ph.D., professor of environmental engineering at the University of California, Irvine, and an author of the paper. Because water quality changes so rapidly, an effective single-sample program would require minute-by-minute updates. "You'd have to have a stop light up on the beach flashing green and red," he said. "It flashes red and everybody would have to run out of the surf; it flashes green and everybody could run back in." Grant favors the use of an averaging method, similar to that used to determine unsafe air quality in urban areas.
The high number of closings based on the single-sample method has prompted public concern about water quality at America's beaches. At Huntington Beach, however, the researchers found that the water quality has been improving over time in response to large-scale investment in waste treatment and disposal in the region.
"I think there's actually a positive environmental message here," Grant said. "There's been a lot of money spent over the years on mitigation and we can clearly see the impacts of that."
In October 2000, Congress passed the federal BEACH act, which is designed to ensure consistent national health standards for beach water by 2004. States will have to meet Environmental Protection Agency standards to receive federal funding for the monitoring programs.
The EPA has not issued final rules for implementing the BEACH act, and Grant is concerned that the bill could turn the single-sample standard into law. Current EPA guidelines do include an averaging method, but local authorities are far from consistent in their sampling strategies, according to the NRDC report.
Other research by Grant and his team also goes against conventional wisdom about coastal water pollution. In the June 15, 2001, issue of Environmental Science and Technology, they published a paper uncovering evidence that bird droppings in a nearby wetland contributed fecal matter to Huntington Beach, raising the levels of hazardous bacteria in the water. Those findings contradict a longstanding belief that wetlands filter out pollutants. The researchers recently received a grant to continue this investigation by studying other wetlands on the California coast.
The current project was supported by the National Water Research Institute and matching funds from cities in the region.
-- Jason Gorss