Fecal contamination at beaches has already been well-acknowledged by environmental groups and scientists, hence the "no swimming" signs posted at some beaches.

Persistent beach lovers tend to ignore the warnings, however. In this new study, researchers found that playing beach volleyball or building sand castles may potentially be more dangerous than swimming in terms of fecal contamination hazards.

Previous studies suggest that more fecal bacteria is found in beach sands than in the nearby waters of the ocean, from 10 to 100 times higher. Researchers decided to investigate the modification patterns of bacterial populations in sands over time.

Researchers from the University of Hawaii at Manoa developed laboratory microcosms of sands found at the beach as well as sea water contaminated with sewage. This is to identify the manner in which the general population of the bacteria, including other fecal inhabitants that may cause illnesses, would change over a period of time, studying what they call the decay kinetics of wastewater bacteria and the change of microbial communities in beach sand and seawater.

The findings of the study, published in the journal Environmental Science & Technology, show that the microbial groups decompose at a slower pace in a beach sand environment model compared with when they are placed in the water. This finding may help point out why more bacteria from fecal matter is found on the sands of the beaches, compared with what's found in the waves.  

The manner in which bacteria from feces gets to the beaches and onto its sands is now the main point of question. According to the Minnesota Lake Superior Costal Program, the exact mechanisms of fecal bacteria settling may be challenging to detect as the different elements of the environment such as the wind, water and weather patterns are complex. The bacteria usually come from warm-blooded waterfowl, domesticated and wildlife animals. Water systems can be polluted with the bacteria through direct deposition, flood water contact, damage of sewage systems and incorrect disposal of wastes, among many others.

When fecal matter comes in contact with food, people may experience signs and symptoms such as abdominal pain, nausea, vomiting, diarrhea, weakness, low-grade fever and headache. More serious health risks are involved if the person exposed to the contamination has a highly compromised immune system or is an infant, a young child or elderly.

Photo: Avolore | Flickr