Playing in dirty sand or swimming in contaminated water can make people sick
A study found that sand can also contain high levels of faecal bacteria, and that people who dig in it can get sick.
Swimming in water that contains too much bacteria from sewage and other sources is a well-known risk for getting sick.
But playing in sand next to that water may be even riskier, a new study finds.
Writing in The American Journal of Epidemiology, researchers said the sand could also contain high levels of faecal bacteria, and that people who dig in it could develop gastrointestinal illnesses.
For the study, researchers got contact information from more than 25,000 people visiting seven beaches within seven miles of sewage treatment plants.
About 10 days later, the researchers asked how they had spent their day at the beach and whether they had experienced problems like vomiting or diarrhoea since then.
Those who dug in the sand, the study found, were significantly more likely to report having been sick — with those who had allowed themselves to be buried in the sand most affected. Children seemed to be at extra risk.
It is not uncommon for swimming to be temporarily banned when there are high levels of faecal bacteria, often from treatment plants, runoff from cities or animal life, until the water clears.
It may be more complex when sand is involved, said the lead author of the study, Christopher D. Heaney of the University of North Carolina in Chapel Hill.
It may be that the bacteria can continue to live in the sand even after the bacteria in the water has returned to normal levels.
Heaney said people should wash their hands before they eat on the beach.