Variability of E. coli density and sources in an urban watershed

Wu, Jianyong; Rees, Paula L.; Dorner, Sarah

doi:10.2166/wh.2010.063

Cited by 31 publications

(13 citation statements)

References 34 publications

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“…A similar phenomenon has been observed in an urban watershed, where heavy storms led to an increase in E. coli concentration. 34 The results showed air temperature has a complicated relationship with E. coli presence and concentration, which might be explained as follows. First, air temperature does not have a linear relationship with groundwater temperature.…”

Section: Discussionmentioning

confidence: 99%

Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh

Yunus

Islam

et al. 2016

Environ. Sci. Technol.

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Climate extremes in conjunction with some land use practices are expected to have large impacts on water quality. However the impacts of land use and climate change on fecal contamination of groundwater has not been well characterized. This work quantifies the influences of extreme weather events and land use practices on E. coli presence and concentration in groundwater from 125 shallow wells, a dominant drinking water resource in rural Bangladesh, monitored over a 17-month period. The results showed that E. coli presence was significantly associated with the number of heavy rain days, developed land and areas with more surface water. These variables also had significant impacts on E. coli concentration, with risk ratios of 1.38 (95% CI = 1.16, 1.65), 1.07 (95% CI: 1.05, 1.09), and 1.02 (95% CI = 1.01, 1.03), respectively. Significant synergistic effects on E.coli presence and concentration were observed when land use and weather variables were combined. The findings suggest that climate extremes and land use practices, particularly urbanization, might promote fecal contamination of shallow well water, thus increasing the risk of diarrheal diseases.

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Section: Discussionmentioning

confidence: 99%

Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh

Yunus

Islam

et al. 2016

Environ. Sci. Technol.

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“…High variability in measurements of indicator concentrations have been observed in this study region 32 and in temperate coastal waters 33 from short to long timescales. Wu and others 34 found that the density of E. coli in an urban watershed in Massachusetts displayed a high degree of spatial and temporal variability, and was highly influenced by both weather and surrounding land use. Wide variability has been observed between the ten U.S. EPA-approved tests to detect and quantify total coliforms and E. coli.…”

Section: Discussionmentioning

confidence: 99%

Rethinking Indicators of Microbial Drinking Water Quality for Health Studies in Tropical Developing Countries: Case Study in Northern Coastal Ecuador

Lévy

Nelson

Hubbard

et al. 2012

The American Society of Tropical Medicine and Hygiene

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Abstract. To address the problem of the health impacts of unsafe drinking water, methods are needed to assess microbiologic contamination in water. However, indicators of water quality have provided mixed results. We evaluate five assays (three for Escherichia coli and one each for enterococci and somatic coliphage) of microbial contamination in villages in rural Ecuador that rely mostly on untreated drinking water. Only membrane filtration for E. coli using mI agar detected a significant association with household diarrheal disease outcome (odds ratio = 1.29, 95% confidence interval = 1.02-1.65 in household containers and odds ratio = 1.18, 95% confidence interval = 1.02-1.37) in source samples. Our analysis and other published research points to the need for further consideration of study design factors, such as sample size and variability in measurements, when using indicator organisms, especially when relating water quality exposure to health outcomes. Although indicator organisms are used extensively in health studies, we argue that their use requires a full understanding of their purposes and limitations.

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“…The importance of precipitation and streamflow in the transport of protozoan and bacterial pathogens and fecal indicator bacteria in lotic systems has been frequently reported (Ferguson et al, 2003;Dorner et al, 2006;Wu et al, 2011;Duris et al, 2013), but only a handful of studies have related these environmental factors to virus transport and the findings have not been consistent. Rainfall or elevated river flow was associated with increased detection frequencies or increased virus concentrations at various sites in the area near Galveston, TX (Gerba et al, 1979), the Chicago area waterway system (Rijal et al, 2009), and the Atlamaha River, Georgia .…”

Section: Discussionmentioning

confidence: 99%

Human and bovine viruses in the Milwaukee River watershed: Hydrologically relevant representation and relations with environmental variables

Corsi

Borchardt

Spencer

et al. 2014

Science of The Total Environment

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To examine the occurrence, hydrologic variability, and seasonal variability of human and bovine viruses in surface water, three stream locations were monitored in the Milwaukee River watershed in Wisconsin, USA, from February 2007 through June 2008. Monitoring sites included an urban subwatershed, a rural subwatershed, and the Milwaukee River at the mouth. To collect samples that characterize variability throughout changing hydrologic periods, a process control system was developed for unattended, large-volume (56-2800 L) filtration over extended durations. This system provided flow-weighted mean concentrations during runoff and extended (24-h) low-flow periods. Human viruses and bovine viruses were detected by real-time qPCR in 49% and 41% of samples (n=63), respectively. All human viruses analyzed were detected at least once including adenovirus (40% of samples), GI norovirus (10%), enterovirus (8%), rotavirus (6%), GII norovirus (1.6%) and hepatitis A virus (1.6%). Three of seven bovine viruses analyzed were detected including bovine polyomavirus (32%), bovine rotavirus (19%), and bovine viral diarrhea virus type 1 (5%). Human viruses were present in 63% of runoff samples resulting from precipitation and snowmelt, and 20% of low-flow samples. Maximum human virus concentrations exceeded 300 genomic copies/L. Bovine viruses were present in 46% of runoff samples resulting from precipitation and snowmelt and 14% of low-flow samples. The maximum bovine virus concentration was 11 genomic copies/L. Statistical modeling indicated that stream flow, precipitation, and season explained the variability of human viruses in the watershed, and hydrologic condition (runoff event or low-flow) and season explained the variability of the sum of human and bovine viruses; however, no model was identified that could explain the variability of bovine viruses alone. Understanding the factors that affect virus fate and transport in rivers will aid watershed management for minimizing human exposure and disease transmission.

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Variability of E. coli density and sources in an urban watershed

Cited by 31 publications

References 34 publications

Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh

Influence of Climate Extremes and Land Use on Fecal Contamination of Shallow Tubewells in Bangladesh

Rethinking Indicators of Microbial Drinking Water Quality for Health Studies in Tropical Developing Countries: Case Study in Northern Coastal Ecuador

Human and bovine viruses in the Milwaukee River watershed: Hydrologically relevant representation and relations with environmental variables

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