Persistence of fecal indicator bacteria and associated genetic markers from wastewater treatment plant effluents in freshwater microcosms.

Limited information exists on the environmental persistence of genetic markers for fecal indicator bacteria (FIB) in treated wastewaters. Here, the decay rate constants of culturable cells and genetic markers for four diverse groups of FIBs, such as enterococci, Clostridium, Escherichia coli, and Bacteroides, were investigated in freshwater microcosms seeded with disinfected and non-disinfected secondary-treated wastewaters. Decay rate constants of genetic markers and culturable cells varied significantly among the different FIB groups.

Influence of wastewater disinfection on densities of culturable fecal indicator bacteria and genetic markers.

The US Environmental Protection Agency has proposed the use of quantitative polymerase chain reaction (qPCR) as a rapid alternative analytical method for monitoring recreational water quality at beaches. For qPCR to be considered for other Clean Water Act purposes, such as inclusion in discharge permits and use in Total Maximum Daily Load calculations, it is necessary to understand how qPCR detectable genetic markers are influenced by wastewater disinfection. This study investigated genetic markers for Escherichia coli, Enterococcus, Clostridium spp.

Water quality, weather and environmental factors associated with fecal indicator organism density in beach sand at two recreational marine beaches.

Recent studies showing an association between fecal indicator organisms (FIOs) in sand and gastrointestinal (GI) illness among beachgoers with sand contact have important public health implications because of the large numbers of people who recreate at beaches and engage in sand contact activities. Yet, factors that influence fecal pollution in beach sand remain unclear. During the 2007 National Epidemiological and Environmental Assessment of Recreational (NEEAR) Water Study, sand samples were collected at three locations (60 m apart) on weekend days (Sat, Sun) and holidays between June and September at two marine beaches - Fairhope Beach, AL and Goddard Beach, RI - with nearby publicly-owned treatment works (POTWs) outfalls.

Fecal indicators in sand, sand contact, and risk of enteric illness among beachgoers.

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.

Rapidly measured indicators of recreational water quality and swimming-associated illness at marine beaches: a prospective cohort study.

Introduction: In the United States and elsewhere, recreational water quality is monitored for fecal indicator bacteria to help prevent swimming-associated illnesses. Standard methods to measure these bacteria take at least 24 hours to obtain results. Molecular approaches such as quantitative polymerase chain reaction (qPCR) can estimate these bacteria faster, in under 3 hours.

Modeling Enterococcus densities measured by quantitative polymerase chain reaction and membrane filtration using environmental conditions at four Great Lakes beaches.

Data collected by the US Environmental Protection Agency (EPA) during the summer months of 2003 and 2004 at four US Great Lakes beaches were analyzed using linear regression analysis to identify relationships between meteorological, physical water characteristics, and beach characteristics data and the fecal indicator bacteria, Enterococcus. Water samples were analyzed for Enterococcus densities by quantitative polymerase chain reaction (qPCR) and membrane filtration (MF). This paper investigates the ability of regression models to accurately predict Enterococcus densities above or below a threshold value, using environmental data on a beach-by-beach basis for both methods.

Contact with beach sand among beachgoers and risk of illness.

Recent studies of beach sand fecal contamination have triggered interest among scientists and in the media. Although evidence shows that beach sand can harbor high concentrations of fecal indicator organisms, as well as fecal pathogens, illness risk associated with beach sand contact is not well understood. Beach visitors at 7 US beaches were enrolled in the National Epidemiological and Environmental Assessment of Recreational Water (NEEAR) Study during 2003-2005 and 2007 and asked about sand contact on the day of their visit to the beach (digging in the sand, body buried in the sand).

High sensitivity of children to swimming-associated gastrointestinal illness: results using a rapid assay of recreational water quality.

Background: Culture-based methods of monitoring fecal pollution in recreational waters require 24 to 48 hours to obtain results. This delay leads to potentially inaccurate management decisions regarding beach safety. We evaluated the quantitative polymerase chain reaction (QPCR) as a faster method to assess recreational water quality and predict swimming-associated illnesses.

A critical evaluation of a flow cytometer used for detecting enterococci in recreational waters.

The current U. S. Environmental Protection Agency-approved method for enterococci (Method 1600) in recreational water is a membrane filter (MF) method that takes 24 hours to obtain results.

Rapidly measured indicators of recreational water quality are predictive of swimming-associated gastrointestinal illness.

Standard methods to measure recreational water quality require at least 24 hr to obtain results, making it impossible to assess the quality of water within a single day. Methods to measure recreational water quality in View Article and Find Full Text PDF

Indicator bacteria at five swimming beaches-analysis using random forests.

"Random forests," an extension of tree regression, provide a relatively new technique for exploring relationships of a response variable like the density of indicator bacteria in water to numerous potential explanatory variables. We used this tool to study relationships of indicator density at five beaches to numerous other variables and found that day of the week, indicator density 24h earlier, water depth at the sampling point, cloud cover, and others were related to density at one or more of the beaches. Using data from the first 52 days of measurement allowed predicting indicator densities in the following 10 days to order of magnitude at some of the beaches.

Comparison of Enterococcus measurements in freshwater at two recreational beaches by quantitative polymerase chain reaction and membrane filter culture analysis.

Cell densities of the fecal pollution indicator genus, Enterococcus, were determined by a rapid (3 h or less) quantitative polymerase chain reaction (QPCR) analysis method in 100 ml water samples collected from recreational beaches on Lake Michigan and Lake Erie during the summer of 2003. Measurements by this method were compared with counts of Enterococcus colony-forming units (CFU) determined by Method 1600 membrane filter (MF) analysis using mEI agar. The QPCR method had an estimated 95% confidence, minimum detection limit of 27 Enterococcus cells per sample in analyses of undiluted DNA extracts and quantitative analyses of multiple lake water samples, spiked with known numbers of these organisms, gave geometric mean results that were highly consistent with the spike levels.