Spatial and hydrologic variation of Bacteroidales, adenovirus and enterovirus in a semi-arid, wastewater effluent-impacted watershed

Abstract

Bacteroidales and viruses were contemporaneously measured during dry and wet weather conditions at a watershed-scale in a semi-arid watershed impacted by a mixture of agricultural runoff, municipal wastewater effluent and municipal runoff. The results highlight the presence of municipal wastewater effluent as a confounding factor for microbial source tracking (MST) studies, and thus data were segregated into groups based on whether they were impacted by wastewater effluent. In semi-arid environments such as the Calleguas Creek watershed, located in southern California, the relative contribution of municipal wastewater effluent is dependent on hydrology as storm events lead to conditions where agricultural and municipal stormwater dominate receiving waters (rather than municipal wastewater, which is the case during dry weather). As such, the approach to data segregation was dependent on hydrology/storm conditions. Storm events led to significant increases in ruminant- and dog-associated Bacteroidales concentrations, indicating that overland transport connects strong non-human fecal sources with surface waters. Because the dataset had a large number of non-detect samples, data handling included the Kaplan–Meir estimator and data were presented graphically in a manner that reflects the potential effect of detection limits. In surface water samples with virus detections, Escherichia coli concentrations were often below (in compliance with) the recreational water quality criteria. In fact, sites downstream of direct inputs of municipal wastewater effluent exhibited the lowest concentrations of E. coli, but the highest concentrations of human-associated Bacteroidales and highest detection rates of human viruses. The toolkit, comprised of the four Bacteroidales assays and human virus assays used, can be successfully applied to inform watershed managers seeking to comply with recreational water quality criteria. However, care should be taken when analyzing data to account for the effect of non-detect samples, sources with differing microbial viability, and diverging hydrologic conditions.Fil: Bambic, Dustin G.. University of California at Davis; Estados UnidosFil: Kildare Hann, Beverly J.. University of California at Davis; Estados UnidosFil: Rajal, Verónica Beatriz. University of California at Davis; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sturm, Belinda S. M.. University of California at Davis; Estados UnidosFil: Minton, Chris B.. Larry Walker Associates; Estados UnidosFil: Schriewer, Alexander. University of California at Davis; Estados UnidosFil: Wuertz, Stefan. University of California at Davis; Estados Unidos. Nanyang Technological University; Singapu

A review on microbial contaminants in stormwater runoff and outfalls: Potential health risks and mitigation strategies

“…Two of five storm outfalls were also positive for gull feces. Bambic et al (2015) reported the moderate occurrence of cattle and dog markers in stormwater samples ranging from 4.67 and 4.75 log 10 GC/L. Storm events led to an increase (4.67 and 4.75 log 10 GC/L) in cattle and dog feces-associated Bacteroides marker genes compared to dry events (3.23 and 3.20 log 10 GC/L).…”

“…In general, concentrations of pathogens in stormwater are poorly reported and some data may not be useful to infer risk or for quantitative microbial risk assessment (QMRA). For example, several studies have failed to detect or provided the percentage of samples positive for pathogens without giving quantitative numbers (Surbeck et al, 2006;Rajal et al, 2007;Sidhu et al, 2012a;Bambic et al, 2015). Most of the stormwater studies determined the concentrations of genus Cryptosporidium and Giardia.…”

Evaluating Microbial and Chemical Hazards in Commercial Struvite Recovered from Wastewater

“…Human enteric viruses related to waterborne outbreaks could also be a concern in nutrient recovery from wastewater. , These viruses include noroviruses GI and GII (NoVs) and human adenoviruses (HAdVs), both associated with acute gastrointestinal infections in children and adults via environmental routes, , along with Enterovirus (EV) members, which can lead to various chronic diseases . While WWTPs may reduce viral loads to receiving environments, persistent virions − such as noroviruses have been associated with spinach crop outbreaks from reclaimed wastewater uses .…”

“…32,33 These viruses include noroviruses GI and GII (NoVs) and human adenoviruses (HAdVs), both associated with acute gastrointestinal infections in children and adults via environmental routes, 34,35 along with Enterovirus (EV) members, 36 which can lead to various chronic diseases. 37 While WWTPs may reduce viral loads to receiving environments, persistent virions 38−40 such as noroviruses have been associated with spinach crop outbreaks from reclaimed wastewater uses. 41 Furthermore, analysis of a human virus surrogate (somatic bacteriophage ϕX174) in struvite recovered from urine shows that inactivation and infectivity can be affected by moisture content.…”

Coliphage as an Indicator of the Quality of Beach Water to Protect the Health of Swimmers in Coastal Georgia

“…Recreational water illnesses occur by exposure to contaminated waters in lakes, streams, pools, and oceans through activities such as fishing, swimming, or boating (Colford et al, 2007). These water bodies are vulnerable to contamination with pathogens from a variety of sources that can include septic tank malfunctions, the introduction of wastewater, storm drain contamination, and fecal discharge from animals and humans directly into the water (Withers et al, 2014;Bambic et al, 2015). Upon contact with contaminated recreational waters, children are at greater risk of gastroenteritis (Oh et al, 2003;Jones et al, 2014;Kotwal and Cannon, 2014).…”