Principal investigator Helena Solo-Gabriele, a professor at the University of Miami College of Engineering, and Tomoyuki Shibata of the Northern Illinois University, said they wanted to determine what levels of bacteria, or pathogens, found in beach sand could pose a health risk for beachgoers.
"The environments in the sand and water are very different," Solo-Gabriele said in a statement. "The sand provides more protection against the effects of solar radiation, which has a tendency to inactivate microbes in water. Sand may also protect microbes from predators -- other microbes -- that are found exclusively in water."
The scientists ran 1 million simulations of the number of microbes in each gram of sand, the transfer of sand from hand to mouth and the ingestion rate.
They created a reference guide for potentially harmful germs in sand, similar to the guidelines set by the U.S. Environmental Protection Agency for marine water -- the risk of having 19 cases of bacterial infection per 1,000 beachgoers.
However, studies showed children have a higher illness risk than adults from beach and sand exposures and the researchers will focus on studies of kids' play behavior in sand.
"Parents of young children don't need to overreact to our findings and they can reduce their child's infectious risk by basic hygiene practices such as hand washing before eating or drinking and taking a shower," Shibata said.