Occurrence of coliphage in raw wastewater and in ambient water: A meta-analysis

Abstract

Coliphage have been proposed as indicators of fecal contamination in recreational waters because they better reflect the persistence of pathogenic viruses in the environment and through wastewater treatment than traditional fecal indicator bacteria. Herein, we conducted a systematic literature search of peer-reviewed publications to identify coliphage density data (somatic and male-specific, or MSC) in raw wastewater and ambient waters. The literature review inclusion criteria included scope, study quality, and data availability. A non-parametric two-stage bootstrap analysis was used to estimate the coliphage distributions in raw wastewater and account for geographic region and season. Additionally, two statistical methodologies were explored for developing coliphage density distributions in ambient waters, to account for the nondetects in the datasets. In raw wastewater, the analysis resulted in seasonal density distributions of somatic coliphage (SC) (mean 6.5 log 10 plaque forming units (PFU)/L; 95% confidence interval (CI): 6.2-6.8) and MSC (mean 5.9 log 10 PFU/L; 95% CI: 5.5-6.1). In ambient waters, 49% of MSC samples were nondetects, compared with less than 5% for SC. Overall distributional estimates of ambient densities of coliphage were statistically higher for SC than for MSC (mean 3.4 and 1.0 log 10 PFU/L, respectively). Distributions of coliphage in raw wastewater and ambient water will be useful for future microbial risk assessments.

Microbial Indicators of Fecal Pollution: Recent Progress and Challenges in Assessing Water Quality

“…Associations between indicators and pathogens in surface water have been largely inconsistent, although empirical determination of these relationships is challenged by the limitations of direct pathogen detection; associations are more commonly observed among more frequently detected organisms [ 27 , 36 ]. Microbial occurrence is more consistent in feces and particularly in sewage, which smooths the high individual variability in fecal microbe shedding by representing the combined fecal inputs of populations [ 177 , 178 , 180 – 182 ]. Despite less frequent detection of alternative indicators in recreational waters [ 27 ], high concentrations of multiple human-associated markers have been reported worldwide in both raw and biologically treated wastewater [ 83 •].…”

“…Despite less frequent detection of alternative indicators in recreational waters [ 27 ], high concentrations of multiple human-associated markers have been reported worldwide in both raw and biologically treated wastewater [ 83 •]. Meta-analyses have also found high coliphage and norovirus densities in raw sewage around the world [ 178 , 180 ]. A wide range of pathogens have frequently been detected in stormwater, though with greater variability and typically at lower concentrations than in sewage [ 179 ].…”

Viral and Bacterial Fecal Indicators in Untreated Wastewater across the Contiguous United States Exhibit Geospatial Trends

“…In response to these limitations, rapid molecular biology-based technologies that can measure enterococci and E. coli in a matter of hours, offering the option for same-day water quality notification, have been developed (10)(11)(12). Other researchers are investigating the use of viral cultures for surface water quality monitoring that target somatic and F ϩ coliphages (13)(14)(15)(16). Coliphage monitoring may offer a more public health-protective approach due to the increased similarities of coliphages to enteric viral pathogens in morphology, inactivation in the environment, and persistence during treatment (17)(18)(19).…”

A Somatic Coliphage Threshold Approach To Improve the Management of Activated Sludge Wastewater Treatment Plant Effluents in Resource-Limited Regions

“…Currently, human enteric viruses cause a significant fraction of the disease burden related to wastewater pollution worldwide. Direct and indirect wastewater reuse (e.g., agricultural irrigation, recreational activities in contaminated surface waters) represents a public health risk; thus, the microbial quality of WWTP effluent should be monitored to manage those risks (11,12).…”