| Marine recreational waters are intensely monitored to protect swimmers from waterborne pathogens. However, because direct measurement of waterborne pathogens is too slow and costly, microbiological water quality is routinely assessed by enumeration of fecal indicator bacteria (FIB) (total coliform, fecal coliform/E. coli, and enterococci), acceptable levels of which have been established through epidemiological studies. Despite their wide use, many questions regarding the efficacy of using indicator organisms remain.;This dissertation (1) examined the comparability of U.S. Environmental Protection Agency (USEPA)-approved methods for measurement of FIB; (2) assessed the use of FIB and viruses to identify and quantify sources of fecal contamination in water; (3) evaluated the equivalency of new, more rapid methods to measure FIB to USEPA-approved methods; and (4) investigated bacteriological water quality at beaches with minimal human impacts during wet weather.;USEPA-approved methods for FIB were comparable for E. coli and enterococci but not for total coliforms. Genetic methods and viruses were most accurate for identification of human sources of fecal contamination, but no method evaluated identified or quantified all sources of fecal contamination. Three new, rapid molecular methods for measuring FIB were equivalent to USEPA-approved methods on about 80% of samples in regard to water-quality criteria for enterococci and would have triggered the same beach management decision about 75% of the time. FIB from non-human sources were great enough to trigger beach water quality warnings during wet weather.;Current methods to enumerate FIB are too slow to protect swimmers from waterborne pathogens. Development and implementation of methods that measure FIB in a few hours are likely within the foreseeable future. However, the inability to track sources of FIB and their prevalence at non-human-impacted beaches brings the efficacy of FIB as a predictor of waterborne pathogens-absent the presence of human sewage-into question.;Continued development and validation in epidemiological studies of new, rapid indicators of fecal contamination and of methods that directly detect waterborne pathogens are imperative to prevent unnecessary beach water quality warnings and protect swimmers from waterborne diseases when pathogens are actually present. |
