A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
An assessment of total coliforms as a water quality indicator for Ontario private drinking water wells
Private drinking water systems in Ontario are unregulated, leaving the maintenance of private wells in the province as responsibilities of well owners. A static non-zero total coliform (TC) concentration threshold of 5 colony-forming units (CFU) per 100 mL is used by the provincial public health laboratory to determine whether protective action should be recommended to private well owners. The current study sought to assess the role of the TC group and associated thresholds as microbial water quality parameters, as the authors hypothesized that static non-zero TC thresholds are not justifiable. A microbial water quality dataset containing 795,023 samples (including TC and Escherichia coli (E. coli) counts) collected from 253,136 private wells in Ontario between 2010 and 2017 was used to this end. To accurately assess the relationship between E. coli and non-E. coli TC, the E. coli count for each sample was subtracted from the TC count, resulting in “non-E. coli coliforms” (NEC). This study analysed NEC and E. coli detection rates to determine the influence of drivers on NEC and E. coli contamination, NEC:E. coli concentration ratios to assess links, if any, between NEC and E. coli contamination, and the relationship between NEC concentrations and E. coli detection rates to determine whether private well TC thresholds can be meaningfully associated with the probability of E. coli presence. Study findings suggest that a static non-zero TC threshold that recommends protective action is not justifiable because seasonal (e.g., precipitation totals and groundwater extraction volumes), spatial (e.g., aquifer type), and well-specific (e.g., well depth and well type) factors influence contamination. As such, it is recommended that the influence of these factors be considered during the development of private groundwater guidelines. Furthermore, no single NEC threshold could be meaningfully linked to the probability of E. coli presence, as findings suggested that the relationship between E. coli detection rates and NEC concentrations is highly dependent on contamination drivers. The authors also proposed that, because NEC:E. coli concentration ratios are influenced by the aforementioned drivers, they may have a role in determining dominant groundwater contamination pathways. ; M.E.S.
An assessment of total coliforms as a water quality indicator for Ontario private drinking water wells
Private drinking water systems in Ontario are unregulated, leaving the maintenance of private wells in the province as responsibilities of well owners. A static non-zero total coliform (TC) concentration threshold of 5 colony-forming units (CFU) per 100 mL is used by the provincial public health laboratory to determine whether protective action should be recommended to private well owners. The current study sought to assess the role of the TC group and associated thresholds as microbial water quality parameters, as the authors hypothesized that static non-zero TC thresholds are not justifiable. A microbial water quality dataset containing 795,023 samples (including TC and Escherichia coli (E. coli) counts) collected from 253,136 private wells in Ontario between 2010 and 2017 was used to this end. To accurately assess the relationship between E. coli and non-E. coli TC, the E. coli count for each sample was subtracted from the TC count, resulting in “non-E. coli coliforms” (NEC). This study analysed NEC and E. coli detection rates to determine the influence of drivers on NEC and E. coli contamination, NEC:E. coli concentration ratios to assess links, if any, between NEC and E. coli contamination, and the relationship between NEC concentrations and E. coli detection rates to determine whether private well TC thresholds can be meaningfully associated with the probability of E. coli presence. Study findings suggest that a static non-zero TC threshold that recommends protective action is not justifiable because seasonal (e.g., precipitation totals and groundwater extraction volumes), spatial (e.g., aquifer type), and well-specific (e.g., well depth and well type) factors influence contamination. As such, it is recommended that the influence of these factors be considered during the development of private groundwater guidelines. Furthermore, no single NEC threshold could be meaningfully linked to the probability of E. coli presence, as findings suggested that the relationship between E. coli detection rates and NEC concentrations is highly dependent on contamination drivers. The authors also proposed that, because NEC:E. coli concentration ratios are influenced by the aforementioned drivers, they may have a role in determining dominant groundwater contamination pathways. ; M.E.S.
An assessment of total coliforms as a water quality indicator for Ontario private drinking water wells
Petculescu, Ioan (author) / Majury, Anna / Brown, Stephen / Hynds, Paul / Environmental Studies
2021-10-28
Theses
Electronic Resource
English
DDC:
690
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