Beach Pollution Sampling Methods May Be Flawed
Beach closures could be blamed on flawed sampling methods, not just pollution
Irvine, Calif., August 15, 2002 -The surf may be up at California's Huntington Beach, but pollution levels are down. A study led by scientists at The Henry Samueli School of Engineering at UC Irvine suggests the recent rash of beach closures could be partially due to flawed sampling techniques.
The findings are reported in Research ASAP in the 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 studies, the researchers characterized the surf water quality at Huntington Beach, California. 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 a complex mixture of physical and biological factors, such as tidal cycles, seasonal rainfall and El Nino events. They also discovered that, contrary to popular belief, water quality at Huntington Beach has improved over the years in response to infrastructure upgrades.
"I think there's actually a positive environmental message here," said Stanley Grant, chair of the UCI Department of Chemical Engineering and Materials Science and lead author of the paper. "There's been a lot of money spent over the years on mitigation and we can clearly see the impacts of that. There's evidence in the record that when you spend 10 million bucks cleaning up a sewage outfall it actually pays off."
The findings do, however, raise questions about existing beach water 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 Grant. Because water quality varies 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.
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, however, 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. The 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. Paper co-authors are Alexandria B. Boehm of Stanford University, Joon H. Kim of UC Irvine, Samuel L. Mowbray and Charles D. McGee of Orange County Sanitation District, and Catherine D. Clark, Denise M. Foley and Daniel E. Wellman of Chapman University.
The Henry Samueli School of Engineering encompasses five departments: biomedical engineering, civil and environmental engineering, chemical engineering and materials science, electrical and computer engineering and mechanical and aerospace engineering. The school also is home to numerous research centers, including the National Fuel Cell Research Center, Integrated Nanosystems Research Facility and Center for Biomedical Engineering. Additional information is available at www.eng.uci.edu.