Sand Play Gets Dirty

Yes, I am responsible for sullying this dune on Fraser Island.

I’m only human.

I’ve always been under the impression that spending time in the sand, amidst the mineral rich deposits of broken down sea things was equivalent to an expensive spa treatment. However, researchers are now finding a link between sand play, digging, or burying, and gastrointestinal illness.

That is, they are discovering that fecal matter is becoming more prevalent in the composition of the sand that lines our coasts and have documented the increased risk of “gastrointestinal illnesses, upper respiratory illnesses, rash, eye ailments, earache and infected cuts.”

An earlier, related story close to home…..

Fecal Microorganisms Inhabit Sandy Beaches Of Florida

ScienceDaily (May 14, 2008) — Traditionally, the cleanliness of a beach is monitored by sampling the bathing water a few meters from shore. But since sand is an effective filter, it follows that fecal bacteria (those from sewage) may be concentrated in the sand as the tide flows and ebbs. Moreover, trapped bacteria are offered a large surface area for attachment, nourishment from nutrients in sand crevices, and protection from sunlight. These bacteria might be afforded greater survival opportunities and may even be nourished enough to replicate in the beach environment.

Dr. Andrew Rogerson, formally of the Oceanographic Center of Nova Southeastern University, Florida, headed an Environmental Protection Agency study to determine the levels of fecal-derived bacteria in Florida beach sand and look for health implications. Early results showed that wet sand (in the intertidal zone) and dry sand above the intertidal zone had significantly more fecal bacteria than near-shore seawater. This lead to the question – do indicator bacteria survive longer in sand relative to open water? A series of laboratory experiments were conducted to answer this question and the results are presented in the May-June issue of Journal of Environmental Quality.

All the feces-derived bacteria (i.e. traditional indicators of sewage contamination) were capable of enhanced survival in sand and, more importantly, were capable of growth in the sand leading to much higher numbers. Conversely, in seawater the bacteria steadily decreased in number over time. Results also showed a rapid drop off in bacterial numbers in bathing water sampled close to the sand compared with 5, 10 or 20 m from shore. This indicates that the shoreline water is affected by bacterial run-off from the sand.

This has implications for beach managers since the number of bacteria from feces (fecal bacteria) in the water is used to assess the presence of sewages. A high count of these ‘indicator bacteria’ would require the beach to be closed, an a
ction with financial consequences in tourist rich regions such as Florida. Any bacteria washed from the sand complicates the interpretation of counts in the water and could lead to unnecessary beach closures. On the other hand, high numbers of fecal-derived bacteria growing in the sand could constitute an increased health risk.



  1. Do you have a link to the study that showed the increase? I'm wondering if the increase in illness is proportional to the increasing number of people going to the beach, or if the amount of bacteria has actually increased.

  2. Hi Rob,I suspect that the increase is proportional to the growing number of folks/pets at the beach, but also the beaches proximity to waste treatment plants. I don't have a direct link to the study, but you can check it out in a recent edition of the American Journal of Epidemiology. Thanks for the comment!

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