Prevalence and Survival of Microorganisms in Shoreline Interstitial Waters: A Search for Indicators of Health RisksEPA Grant Number: R828830
Title: Prevalence and Survival of Microorganisms in Shoreline Interstitial Waters: A Search for Indicators of Health Risks
Investigators: Rogerson, Andrew , Estiobu, Nwadiuto , McCorquodale, Don
Institution: Nova Southeastern University Oceanographic Center , Florida Atlantic University - Boca Raton
EPA Project Officer: Nolt-Helms, Cynthia
Project Period: August 1, 2001 through July 31, 2003
Project Amount: $312,570
RFA: Recreational Water Quality: Indicators and Interstitial Zones (2000) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water , Ecological Indicators/Assessment/Restoration
There are clues in the literature which, taken together, suggest that the microbiological quality of beach sand may constitute a health risk to bathers, particularly children who spend time in the 'swash zone'. Sand can act as a filter to trap and concentrate bacteria, spores, and cysts. It has a large surface area for microbial attachment, ample oxygen levels, higher temperatures and a constant re-supply of nutrients through wave action and tides. We postulate that potentially pathogenic organisms accumulate in interstitial space where they exploit localized favorable conditions. These organisms are periodically swept from surfaces and are transported to the surf zone where they pose a health risk aggravated by the abrasive nature of sand, the ingestion of contaminated waters, and the inhalation of aerosols rich in microbes. Thus, individuals exposed to the surf zone of populated beaches may show a higher incidence of illnesses from either enteric or non-enteric pathogens.
The study will be completed in four parts. (1) Documentation of the number of ?classic' fecal indicators in sand (E. coli, enterococci, and fecal coliforms), paying attention to whether they are free in interstitial space or attached (and possibly metabolically active) to sand particles. We shall also consider the possibility that some of these organisms are lofted into the air. (2) Enumeration of other non-indigenous microorganisms in sand including non-enterics, coliphage and several eukaryotic microbes. (3) Monitoring of a laboratory-based microcosm to study the survival (and growth) of indicator organisms in sand relative to overlying open water. (4) Correlation of microbial abundance data to incidences of beach-related indicators via a detailed questionnaire.
The results will show whether there is an identifiable health risk to bathers who come in contact with wet beach sand. Our results will indicate whether beach management action is appropriate or whether the health risk of wet sand is negligible.