Background: Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear.
Methods: In 2007, visitors at 2 recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days later, participants answered questions about health symptoms since the visit. F+ coliphage, Enterococcus, Bacteroidales, fecal Bacteroides, and Clostridium spp. in wet sand were measured using culture and molecular methods.
Results: We analyzed 144 wet sand samples and completed 4999 interviews. Adjusted odds ratios (aORs) were computed, comparing those in the highest tertile of fecal indicator exposure with those who reported no sand contact. Among those digging in sand compared with those not digging in sand, a molecular measure of Enterococcus spp. (calibrator cell equivalents/g) in sand was positively associated with gastrointestinal (GI) illness (aOR = 2.0 [95% confidence interval (CI) = 1.2–3.2]) and diarrhea (2.4 [1.4–4.2]). Among those buried in sand, point estimates were greater for GI illness (3.3 [1.3–7.9]) and diarrhea (4.9 [1.8–13]). Positive associations were also observed for culture-based Enterococcus (colony-forming units/g) with GI illness (aOR digging = 1.7 [1.1–2.7]) and diarrhea (2.1 [1.3–3.4]). Associations were not found among nonswimmers with sand exposure.
Conclusions: We observed a positive relationship between sand-contact activities and enteric illness as a function of concentrations of fecal microbial pollution in beach sand.
From the aDepartment of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC; bEpidemiology Branch, Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Research Triangle Park, NC; cNational Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH; dDepartment of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland; and eDepartment of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC.
Correspondence: Christopher D. Heaney, Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD 21205. E-mail: firstname.lastname@example.orgD.
Supported by US Environmental Protection Agency Cooperative Training in Environmental Sciences Research EPA CR83323601; National Institute of Environmental Health Sciences Environmental Epidemiology Training Grant (T32 ES007018), UNC Department of Biostatistics; Kellogg Health Scholars Program–Community Track, UNC Center for Health Promotion and Disease Prevention. The authors reported no other financial interests related to this research.
This document has been subjected to review by the National Health and Environmental Effects Research Laboratory and approved for publication. Approval does not signify that the contents reflect the views of the Environmental Protection Agency.
Submitted 4 April 2011; accepted 18 August 2011.