Year of Publication



Public Health

Degree Name

Master of Public Health (M.P.H.)

Committee Chair

Dr. Wayne Sanderson

Committee Member

Dr. Timothy Prince

Committee Member

Dr. Kathleen Winter


Background: Access to clean water and sanitation is known to decrease childhood mortality, improve health outcomes, and decrease risk of water-borne diseases. However, access to clean water is often restricted in impoverished or indigenous communities. This cross-sectional study evaluated the primary source of drinking water for forty homes, the Est. Cheche river, a local spring, and a local school in the TsáChila indigenous community of El Bua, Santo Domingo, Ecuador. This analysis focused on the presence of coliforms and E. coli in the water source (well or city/piped), the physical parameters of the water and the type of sanitation facilities in the home. Comparisons were made between water source and level of contamination and water source and physical parameters, and physical parameters and level of contamination with coliform or fecal bacteria.

Methods: Analysis of the water samples for total coliforms and E.coli was completed with the IDEXX Colilert and Quanti-Tray 2000 system. Samples were taken from the primary drinking water source of 40 homes, the local river (Este. Cheche) and associated spring, and the local school. Each sample was tested for pH, conductivity, total dissolved solids, salinity and temperature using an Oakton® PCSTestr 35. In the field laboratory, 100 milliliters of each sample were mixed with the Colilert substrate, shaken to mix the substrate into solution, and placed into the quanti-trays and incubated at room temperature (approximately 25° C) for 24 hours. The following day the samples were counted for total coliforms and E. coli quantification was reported in MPN (most probable number). A member of each household was questioned about water usage, number of people using the water source, and illnesses. Using SAS Systems software, univariate and bivariate stratified analysis of selected variables was conducted using chi-squared tests and Fisher’s Exact test for categorical variables, and t-tests for continuous variables. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were also constructed.

Source of Data: Site visit to the El Bua community of Santo Domingo de los TsáChilas, Ecuador on June 4-5, 2018 during the June Shoulder to Shoulder Global Ecuador Brigade.

Results: Statistically significant associations were found between coliform and fecal contamination in samples from wells compared to samples from piped water (p < 0.0001). These persisted when the dependent variables were grouped categorically or used continuously.

Statistically significant differences were also found in pH, salinity, and conductivity by water source (p < 0.0001). Illnesses, including gastrointestinal disease, were not associated with water source. Grouping of symptoms into upper or lower gastrointestinal illnesses was also not associated with water source.

Conclusion: This cross-sectional environmental study of well water and city piped water quality in the TsáChila community of El Bua, Ecuador showed that well water is significantly more likely to be contaminated with coliforms or E. coli, when compared to city piped water. While coliform bacteria and E. coli were also found in piped water samples, the levels tended to be much lower than the well samples. Future interventions should focus on increasing access and affordability of city piped water.

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