Microbial source tracking and spatial analysis of E. coli contaminated private well waters in southeastern Ontario

Abstract

Private water supplies, which are the primary source of drinking water for rural communities in developed countries, are at risk of becoming fecally contaminated. It is important to identify the source of contamination in order to better understand and address this human health risk. Microbial source tracking methods using human, bovine and general Bacteroidales markers were performed on 716 well water samples from southeastern Ontario, which had previously tested positive for Escherichia coli. The results were then geospatially analyzed in order to elucidate contamination patterns. Markers for human feces were found in nearly half (49%) of all samples tested, and a statistically significant spatial cluster was observed. A quarter of the samples tested positive for only general Bacteroidales markers (25.7%) and relatively few bovine specific marker positives (12.6%) were found. These findings are fundamental to the understanding of pathogen dynamics and risk in the context of drinking well water and will inform future research regarding host-specific pathogens in private well water samples.

Repeat Sampling and Coliform Bacteria Detection Rates in New Jersey Domestic Wells

“…It is possible that many BK wells in which TC bacteria were detected were impacted by fecal wastes from human sources such as septic tank effluents or leaking sewage collection pipes (Sauer et al ; Kuroda et al ; Bradbury et al ; Hynds et al ; Tollestrup et al ). A study by Krolik et al () showed that 49% of 716 wells in a rural area of Ontario, Canada, were likely impacted by human‐derived fecal wastes. However, it is difficult to envision, as implied from the data in Table , all wells being impacted by such sources.…”

“…Despite the historically accepted status of FC and EC bacteria as fairly reliable indicators of fecal contamination, recent research has shown that, like many members of the TC group of bacteria, indigenous, or environmentally adapted strains are found in the FC and EC bacteria groups as well (e.g., Perchec‐Merien and Lewis ). Krolik et al () found that perhaps as many as 49% of their sampled population of private wells contained E. coli that were likely not derived from either human or bovine fecal sources. We speculate that many wells in the BK region are being impacted by coliform bacteria derived from soil (Byappanahalli et al ), and/or insufficiently filtered surface or storm water sources (Converse et al ; Pandey and Soupir ; Swistock et al ).…”

Prevalence of Microbiological and Chemical Contaminants in Private Drinking Water Wells in Maryland, USA

“…Allevi et al (2013) utilized MST techniques to characterize the magnitude and incidence of microbial contamination in private wells in Virginia, and to identify the likely sources of this contamination [45]. Similarly, Krolik et al (2014, 2016) analyzed well water samples from southeastern Ontario using MST to elucidate whether human or bovine sources were responsible for well contamination [46,47]. Future work relating to our study could include the application of MST methods to help identify the source of microbial contamination in Maryland wells, and to elucidate potential relationships between microbial contamination and environmental characteristics, particularly those relating to land use.…”

A Unified Framework for Robust and Efficient Hotspot Detection in Smart Cities

“…In addition, the discussion will focus on the continuous version of hotspot detection, where statistical population is proportional to geometric area. This continuous version is also widely used in hotspot detection (e.g., [8,16,17,23,26,40,41,45]). Algorithm modifications for the discrete version, in which a statistical population is available and given as a separate point distribution, are beyond the scope of this specific extension and will be explored in future work.…”

“…In public health, hotspots of infections indicate outbreaks of disease [18,20,36,47], which can help officials allocate medical resources and research efforts. In environmental science, hotspots of pollution (e.g., Escherichia coli contamination) help researchers identify the cause and improve urban water quality [16,17]. In urban resilience studies, hotspots of building permits can be used to evaluate the status of recovery from natural disasters (e.g., hurricanes) [40].…”