“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.