Exploring private water wells for fecal sources and evidence of pathogen presence in the context of current testing practices for potability in Ontario (original) (raw)
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Journal of water and health, 2016
Many people living in rural areas rely on privately owned wells as their primary source of drinking water. These water sources are at risk for fecal contamination of human, wildlife, and livestock origin. While traditional bacteriological testing involves culture-based methods, microbial source tracking (MST) assays present an opportunity to additionally determine the source of fecal contamination. This study investigated the main host sources of contamination in private well water samples with high levels of Escherichia coli (E. coli), using MST with human and multi-species specific markers. Fecal contamination of human origin was detected in approximately 50% of samples, indicating that current contamination prevention strategies require reconsideration. The relationship between cattle density and fecal contamination of bovine origin was investigated using a Bovine Bacteroidales specific MST assay. Regional variations of microbial sources were examined, and may inform local primar...
Journal of Water and Health
With increasing stress on our water resources and recent waterborne disease outbreaks, understanding the epidemiology of waterborne pathogens is crucial to build surveillance systems. The purpose of this study was to explore techniques for describing microbial water quality in rural drinking water wells, based on spatiotemporal analysis, time series analysis and relative risk mapping. Tests results for Escherichia coli and coliforms from private and small public well water samples, collected between 2004 and 2012 in Alberta, Canada, were used for the analysis. Overall, 14.6 and 1.5% of the wells were total coliform and E. coli-positive, respectively. Private well samples were more often total coliform or E. coli-positive compared with untreated public well samples. Using relative risk mapping we were able to identify areas of higher risk for bacterial contamination of groundwater in the province not previously identified. Incorporation of time series analysis demonstrated peak conta...
Water Research, 2013
Background: Surface and ground water across the world, including North America, is contaminated with bacteria resistant to antibiotics. The consumption of water contaminated with antimicrobial resistant Escherichia coli (E. coli) has been associated with the carriage of resistant E. coli in people who drink it. Objectives: To describe the proportion of drinking water samples submitted from private sources for bacteriological testing that were contaminated with E. coli resistant to antibiotics and to determine risk factors for the contamination of these water sources with resistant and multi-class resistant E. coli. Methods: Water samples submitted for bacteriological testing in Ontario and Alberta Canada were tested for E. coli contamination, with a portion of the positive isolates tested for antimicrobial resistance. Households were invited to complete questionnaires to determine putative risk factors for well contamination. Results: Using multinomial logistic regression, the risk of contamination with E. coli resistant to one or two classes of antibiotics compared to susceptible E. coli was higher for shore wells than drilled wells (odds ratio [OR] 2.8) and higher for farms housing chickens or turkeys (OR 3.0) than properties without poultry. The risk of contamination with multiclass resistant E. coli (3 or more classes) was higher if the properties housed swine (OR 5.5) or cattle (OR 2.2) than properties without these livestock and higher if the wells were located in gravel (OR 2.4) or clay (OR 2.1) than in loam.
Journal of Water and Health, 2013
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.
Quantitative analysis of microbial contamination in private drinking water supply systems
Journal of Water and Health, 2013
Over one million households rely on private water supplies (e.g. well, spring, cistern) in the Commonwealth of Virginia, USA. The present study tested 538 private wells and springs in 20 Virginia counties for total coliforms (TCs) and Escherichia coli along with a suite of chemical contaminants. A logistic regression analysis was used to investigate potential correlations between TC contamination and chemical parameters (e.g. NO3−, turbidity), as well as homeowner-provided survey data describing system characteristics and perceived water quality. Of the 538 samples collected, 41% (n = 221) were positive for TCs and 10% (n = 53) for E. coli. Chemical parameters were not statistically predictive of microbial contamination. Well depth, water treatment, and farm location proximate to the water supply were factors in a regression model that predicted presence/absence of TCs with 74% accuracy. Microbial and chemical source tracking techniques (Bacteroides gene Bac32F and HF183 detection v...
A spatial analysis of private well water Escherichia coli contamination in southern Ontario
Geospatial Health, 2013
Research to date has provided limited insight into the complexity of water-borne pathogen transmission. Private well water supplies have been identified as a significant pathway in infectious disease transmission in both the industrialised and the developing world. Using over 90,000 private well water submission records representing approximately 30,000 unique well locations in southeastern Ontario, Canada, a spatial analysis was performed in order to delineate clusters with elevated risk of E. coli contamination using 5 years of data (2008-2012). Analyses were performed for all years independently and subsequently compared to each other. Numerous statistically significant clusters were identified and both geographic stability and variation over time were examined. Through the identification of spatial and temporal patterns, this study provides the basis for future investigations into the underlying causes of bacterial groundwater contamination, while identifying geographic regions that merit particular attention to public health interventions and improvement of water quality.
Journal of Water and Health, 2008
Private well owners in Canada are responsible for maintenance, including routine sampling, of their private drinking water supply. Sampling rates in a Southern Ontario community are well below the public health recommendation. A study with private well owners was conducted to improve private well water sampling rates through the removal of two significant barriers to private well water testing. During the pilot and extended study phases, 549 nitrate and 425 bacteriological water sampling bottles were delivered to private well owners and water samples were collected the following day. A follow-up telephone survey was conducted with both study participants and non-participants to identify barriers to private water sampling that were encountered by the study sample population. Participation rates in the pilot and extended study phases were less than 50% prompting the follow-up telephone survey. Inconvenience and lack of time [statistically significant, P < 0.01] were found to be the...
International Journal of Environmental Research and Public Health, 2018
Although many U.S. homes rely on private wells, few studies have investigated the quality of these water sources. This cross-sectional study evaluated private well water quality in Maryland, and explored possible environmental sources that could impact water quality. Well water samples (n = 118) were collected in four Maryland counties and were analyzed for microbiological and chemical contaminants. Data from the U.S. Census of Agriculture were used to evaluate associations between the presence of animal feeding operations and well water quality at the zip code level using logistic regression. Overall, 43.2% of tested wells did not meet at least one federal health-based drinking water standard. Total coliforms, fecal coliforms, enterococci, and Escherichia coli were detected in 25.4%, 15.3%, 5.1%, and 3.4% of tested wells, respectively. Approximately 26%, 3.4%, and <1% of wells did not meet standards for pH, nitrate-N, and total dissolved solids, respectively. There were no statistically significant associations between the presence of cattle, dairy, broiler, turkey, or aquaculture operations and the detection of fecal indicator bacteria in tested wells. In conclusion, nearly half of tested wells did not meet federal health-based drinking water standards, and additional research is needed to evaluate factors that impact well water quality. However, homeowner education on well water testing and well maintenance could be important for public health.
Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2019
Waterborne outbreaks of infectious disease continue to be a public health risk, particularly those in areas where testing of private and public small system groundwater systems is left to the owners/overseers of these wells who may not recognize the importance of testing and treatment. Recognizing factors associated with contamination of wells is important for public safety and can encourage well owners/overseers to test regularly and properly maintain drinking water supplies. Tests results for presence/absence of total coliforms and Escherichia coli for private and public untreated well water for the years 2010-2012 (n ¼ 56,609) were provided by the Alberta Provincial Laboratory for Public Health. Tests were geolocated with the Alberta Township Survey System and aggregated to the quarter section. Agricultural independent variables were provided by the Canadian Agricultural Census and monthly cumulative precipitation was calculated using Alberta Agriculture and Forestry's website of weather station data. Overall frequency of E. colipositive wells in the study was 1.4%. A marginal multivariable logistic regression model was fit using generalized estimating equations to account for repeat testing of some quarter sections. Three significant factors associated with increased E. coli-positive untreated drinking water wells were identified: soil properties (KSat and sand content), animal density and monthly cumulative precipitation.