That is the question researchers with NOAA's University of Southern California Sea Grant program have been studying. They will discuss their findings July 27 and July 28 at the Coastal Zone'99 meeting in San Diego, an international gathering of managers, researcher scientists and policy-makers from 30 nations and 35 U.S. coastal states and territories concerning coastal zone management issues. In America and most other countries of the world, the microbiological safety of beaches is determined by testing for the presence of fecal bacteria. Water found to be clear of bacteria is assumed to be safe. However, a USC Sea Grant study indicates that standard might be misleading because human pathogenic viruses sometimes lurk in bacteria-free water.
Viruses are very different from bacteria.
While they may come from the same sewage contamination source as bacteria, their subsequent fate in water can be dramatically different. Fuhrman and postdoctoral fellow Rachel Noble, who is supported jointly by the USC Wrigley Institute for Environmental Studies and the Southern California Coastal Water Research Project, noted that viruses differ chemically and biologically and are much smaller in size. Under certain conditions, viruses persist longer than bacteria and can be dispersed differently in seawater. The viruses detected were usually in the human enteric virus family, which includes poliovirus, echo-virus and Coxsackie virus. Hepatitis A virus has also been detected.