Cross-Comparison of Human Wastewater-Associated Molecular Markers in Relation to Fecal Indicator Bacteria and Enteric Viruses in Recreational Beach Waters

Abstract

Detection of human wastewater contamination in recreational waters is of critical importance to regulators due to the risks posed to public health. To identify such risks, human wastewater-associated microbial source tracking (MST) markers have been developed. At present, however, a greater understanding of the suitability of these markers for the detection of diluted human wastewater in environmental waters is necessary to predict risk. Here, we compared the process limit of detection (PLOD) and process limit of quantification (PLOQ) of six human wastewater-associated MST markers Among the six MST markers tested, HF183 was the most sensitive measure of human fecal pollution and was quantifiable up to dilutions of 10 Ϫ6 and 10 Ϫ4 for beach water samples seeded with raw and secondary-treated wastewater, respectively. Other markers and enteric viruses were detected at various dilutions (10 Ϫ1 to 10 Ϫ5 ). These MST markers, FIB, and enteric viruses were then quantified in beach water (n ϭ 12) and sand samples (n ϭ 12) from South East Queensland (SEQ), Australia, to estimate the levels of human fecal pollution. Of the 12 sites examined, beach water and sand samples from several sites had quantifiable concentrations of HF183 and PMMoV markers. Overall, our results indicate that while HF183 is the most sensitive measure of human fecal pollution, it should be used in conjunction with a conferring viral marker to avoid overestimating the risk of gastrointestinal illness.IMPORTANCE MST is an effective tool to help utilities and regulators improve recreational water quality around the globe. Human fecal pollution poses significant public health risks compared to animal fecal pollution. Several human wastewaterassociated markers have been developed and used for MST field studies. However, a head-to-head comparison in terms of their performance to detect diluted human fecal pollution in recreational water is lacking. In this study, we cross-compared the performance of six human wastewater-associated markers in relation to FIB and enteric viruses in beach water samples seeded with raw and secondary-treated wastewater. The results of this study will provide guidance to regulators and utilities on the appropriate application of MST markers for tracking the sources of human fecal pollution in environmental waters and confer human health risks.KEYWORDS microbial source tracking, human wastewater, fecal indicator bacteria, beach water, enteric viruses

Pepper mild mottle virus as a water quality indicator

“…34 Beach water samples taken from southeast Queensland, Australia, were tested for PMMoV as an MST organism for fecal pollution of coastal environments. 35 Results from this study yielded only 33.3% (4/12) water samples positive for PMMoV. Concentrations recovered for these samples ranged from 3.6 × 10 4 to 8.6 × 10 4 GC/L ( Table 2).…”

“…1). 28,[31][32][33][34][35] These studies reported that PMMoV was detected in almost all untreated wastewater samples with concentrations greater than 10 5 genome copies (GC)/L ( Table 2). One recent study carried out in Costa Rica documented that the specificity of PMMoV qPCR signal was 100% for domestic wastewater, as compared to 94% specificity of a human-specific (HF183) Bacteroides marker.…”

“…37 PMMoV was also detected in most treated wastewater samples with concentrations greater than 10 4 copies/L ( Table 2). 24,28,[31][32][33][34][35]38 The prevalence of PMMoV in wastewater showed little seasonal variations. 11,31,33 PMMoV showed a higher concentration in wastewater than human enteric viruses.…”

“…11,31,33 PMMoV showed a higher concentration in wastewater than human enteric viruses. 28,[31][32][33][34][35]39 For example, Symonds et al reported that the median and maximum PMMoV concentrations in untreated wastewater were at least an order of magnitude greater than those of human adenovirus (HAdV), human polyomavirus (HPyV), and NoV. 34 This is most likely because PMMoV in human feces is of dietary origin (from peppers and their processed products such as hot sauce and curry), and its presence in feces is not dependent on active infection in humans; therefore it is excreted from large healthy human populations.…”

Occurrence of microbial indicators, pathogenic bacteria and viruses in tropical surface waters subject to contrasting land use

“…somatic and Fþ coliphages), genotypes of FRNA phages and plant virus (i.e. PMMoV) have recently been proposed to allow for better prediction of human pathogens (Hughes et al, 2017;McQuaig et al 2009McQuaig et al , 2012Vergara et al, 2015;Yampara-Iquise et al, 2008). As a result, a number of recent studies have focused on correlations between the alternative indicators and pathogens (Harwood et al, 2014;Jofre et al, 2016).…”