Evaluating the Impact of Geophysical Variables on the Bacterial Contamination of Private Wells in Southern Ontario
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Authors
Wright, Erik
Date
2017-04-24
Type
thesis
Language
en
Keyword
Groundwater , GIS , Statistics , Soil , Geology
Alternative Title
Abstract
Bacterial contamination in groundwater is not often analyzed beyond local and regional scales. The
presence of bacterial contaminants in the groundwater of southern Ontario has been observed, and
several areas have been identified as being at higher relative risk of E. coli contamination (Krolik et
al, 2013). This discovery by Public Health Ontario has prompted further research to evaluate
relationships between observed levels of bacterial contamination and the geological setting of
private wells. Using approximately 38,000 geocoded wells, statistical analysis was performed to
compare overburden depth, soil texture, bedrock classification, and surficial deposit classification
to observed levels of total coliform bacteria and E. coli. A very weak negative correlation was
observed between overburden depth and E. coli, but not total coliform bacteria. One-Way ANOVA
identified statistically significant differences among the means of total coliform bacteria counts in
bedrock and surficial units, but not for E. coli. One-Way ANOVA identified statistically significant
differences among the means of both total coliform bacteria and E. coli in wells situated in soils of
different texture.