Fecal indicator bacteria are abundant in wet sand at freshwater beaches.
Potential fecal contamination of sand in the wave-washed zone of public bathing beaches is overlooked in beach monitoring programs. Activity in this zone can bring pathogens to the sand surface or into the water, presenting a health risk to sensitive populations. On a unit weight basis (colony forming units per 100g), the mean summer abundance of the fecal indicator bacteria enterococci and Escherichia coli was 3-38 times higher in the top 20 cm of wet-sand cores than in the water column at six freshwater bathing beaches. E. coli were 4 times more abundant than enterococci in water but counts were similar in the sand. A correlation (r=0.60) existed between E. coli counts in the water and in the top 5 cm of sand only, whereas no relationship existed between enterococci abundance in water and sand. In general, enterococci were most numerous in the 5-10 cm sand stratum and E. coli in the 0-5 cm stratum. These preliminary data show that wet freshwater beach sand is a reservoir of fecal indicator bacteria. Enteric pathogens may also be present in beach sand.
Wheeler Alm
Elizabeth
E
Department of Biology, Central Michigan University, 157 Brooks Hall, Mount Pleasant, MI 48859, USA. almlew@cmich.edu
Burke
Janice
J
Spain
Anne
A
D016983:Enterococcus / Q000302:isolation & purification*; D004784:Environmental Monitoring / Q000379:methods*; D004926:Escherichia coli / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology*; D005618:Fresh Water; D006801:Humans; D011157:Population Dynamics; D011634:Public Health; D011998:Recreation; D012822:Silicon Dioxide
D012822:Silicon Dioxide