August 13, 2007

Beach Sand Can Harbor Bacteria

The same microbes that result in U.S. beach closures and health advisories when detected at unsafe levels in the ocean are also detected in the sand.

Alexandria Boehm, assistant professor of civil and environmental engineering at Stanford University and graduate students Kevan Yamahara, Blythe Layton and Alyson Santoro collected samples of sand at 55 beaches between Mexico and Oregon and tested for fecal indicator bacteria in the lab and out in the field.

The study, published in the journal Environmental Science and Technology, found that sand at beaches all along the California coast contained some level of fecal indicator bacteria -- 91 percent of the beaches in the study had detectable levels of enterococci and that 62 percent of them had traces of E. coli.

Contaminated beach sands can act as bacteria sources and polluted sand is probably going to act as a source of fecal indicator bacteria to coastal waters-and will impact beach closures and advisories, explained Boehm.

Swimming in water with high levels of bacteria can cause a number of reactions, such as skin rashes or ear infections.