Sharks, flesh-eating bacteria, jellyfish stings...there's another reason beachgoers should be extra-careful when going to the beach this summer, as experts say contaminated sandy beaches could make people sick.
Researchers based at the University of Hawaii have confirmed what scientists have known for many years: there is more presence of fecal contamination on beach sand than beach water.
The experts conducted several laboratory tests of sand, seawater and sewage and found that bacteria is 100 times more abundant in the sand. The bacteria also decays at a longer rate in the soil compared to bacteria present in seawater.
"The different decay rates of wastewater bacteria in beach sand and seawater indicate that beach sand needs to be considered carefully in assessing its impact on water quality monitoring and public health," Qian Zhang, Xia He and Tao Yan wrote in their study, according to ABC News.
"There's a dynamic interface between water and sand," said William Schaffner from Vanderbilt University Medical School. "Fecal indicator bacteria die off more quickly than they do in the sand, at least some of them do. The sand likely keeps feeding and reintroducing indicator bacteria into the water."
"This is not trivial because there are many communities in the world where wastewater is introduced into bodies of water," he added.
When beachgoers find signs that say the beach is closed, most people assume the water is not safe for swimming. But it could also mean that there is pollution in the sand, and thus, it would be more prudent to avoid the beach altogether.
Contaminated sand and seawater can lead to health issues like diarrhea, stomach aches, rashes and skin diseases.
The contamination comes from a complex of sources. Warm blooded animals from humans to seagulls, leaking sewage systems, garbage and accidents from swimmers are just some of the sources of these bacteria, according to Minnesota Lake Superior Beach Monitoring Program.
Beachgoers are advised to be more careful and set towels or mats before laying down on the sand.
The study is published on the journal Environmental Science & Technology.
