"No swimming" signs have already popped up this summer along coastlines where fecal bacteria have invaded otherwise inviting waters. Some vacationers ignore the signs while others resign themselves to tanning and playing on the beach. But should those avoiding the water be wary of the sand, too? New research in the ACS journal Environmental Science & Technology investigates reasons why the answer could be "yes." 
 
 Sewage-contaminated coastal waters can lead to stomach aches, diarrhea and rashes for those who accidentally swallow harmful microbes or come into contact with them. But over the past decade, scientists have been finding fecal bacteria in beach sand at levels 10 to 100 times higher than in nearby seawater. Tao Yan and colleagues wanted to find out why. 
 
 In the lab, the researchers created microcosms of beach sand and seawater contaminated with sewage to see how the overall bacterial populations, including fecal dwellers responsible for causing illness, would change over time. They found that microbial communities tended to decay much slower in the simulated beach sand environment than in the water, which could help explain why more fecal bacteria are found on sandy beaches affected by wastewater pollution than in the waves. 
 
 The authors acknowledge funding from the Hawaii Department of Health. 
 
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 Follow us: Twitter Facebook ||||| What are potential sources of water-borne fecal contamination and fecal bacteria? 
 
 The source or sources of fecal contamination at a beach are often not known for certain because of the complex workings of wind, weather and water patterns, in concert with the origin of fecal contamination, warm-blooded animals. These animals include waterfowl (geese, sea gulls, terns, etc.), wildlife (deer, beaver, rabbits, bear, etc.), domesticated animals (horses, cows, pigs, etc.), pets (dogs, cats, etc.), and humans. 
 
 
 
 Fecal contamination can reach waterways through multiple methods, including direct deposition, stormwater runoff that carries fecal matter from inland, failing or leaking individual septic systems, sanitary sewer systems breakages and overflows, improper diaper disposal, swimmer fecal accidents, improper boat waste disposal, and much more.
– If your response to learning the local beach is closed due to fecal contamination is to wrinkle your nose and lay out your blanket for sunbathing on the sand, you may want to reconsider. A press release on a new study, published in the journal Environmental Science & Technology, notes that scientists have for a decade known what many beachgoers don't: that the fecal bacteria that lurks in sand can be as much as 100 times higher than what's in the adjacent seawater. Researchers at the University of Hawaii at Manoa set out to investigate why. To do so, they conducted "laboratory microcosm experiments" involving beach sand, seawater, and sewage. They found that "common fecal indicator bacteria ... showed significantly smaller decay rates in beach sand than in seawater," essentially confirming the prior research. How does the fecal bacteria get there? A Lake Superior beach monitoring group explains it can be tough to pinpoint exact sources "because of the complex workings of wind, weather, and water patterns." The bacteria originates with "warm-blooded animals" (think everything from humans to sea gulls to deer) and can get to waterways via storm runoff, leaking sewers, improperly discarded diapers, or even from swimmers who have accidents. The press release notes the bacteria can cause stomach aches and diarrhea. (Pools have their own problems: urine.)