Following the Water: A Controlled Study of Drinking Water Storage in Northern Coastal Ecuador

• Type of Material: Article
• Authors: Karen Levy, Emory University; Kara L. Nelson, University of California, Berkeley; Alan Hubbard, University of California, Berkeley; Joseph N.S. Eisenberg, University of Michigan, Ann Arbor
• Language: English
• Date: 2008-07-07
• Publisher: National Institute of Environmental Health Sciences (NIEHS)
• Publication Version: Final Published Version
• Copyright Statement: This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI.
• Final Published Version (URL): http://ehp.niehs.nih.gov/journal-information/
• Title of Journal or Parent Work: Environmental Health Perspectives
• ISSN: 0091-6765
• Volume: 116
• Issue: 11
• Start Page: 1533
• End Page: 1540
• Grant/Funding Information: This work was supported by the University of California Pacific Rim Research Program and the National Institutes of Allergy and Infectious Diseases (R01AI050038).
• Keywords: diarrhea; drinking water quality; recontamination; microbial contamination; Ecuador; point of use; waterborne disease
• Research Categories: Environmental Sciences; Health Sciences, Public Health

Abstract

Background To design the most appropriate interventions to improve water quality and supply, information is needed to assess water contamination in a variety of community settings, including those that rely primarily on unimproved surface sources of drinking water. Objectives We explored the role of initial source water conditions as well as household factors in determining household water quality, and how levels of contamination of drinking water change over time, in a rural setting in northern coastal Ecuador. Methods We sampled source waters concurrently with water collection by household members and followed this water over time, comparing Escherichia coli and enterococci concentrations in water stored in households with water stored under controlled conditions. Results We observed significant natural attenuation of indicator organisms in control containers and significant, although less pronounced, reductions of indicators between the source of drinking water and its point of use through the third day of sampling. These reductions were followed by recontamination in approximately half of the households. Conclusions Water quality improved after water was transferred from the source to household storage containers, but then declined because of recontamination in the home. Our experimental design allowed us to observe these dynamics by controlling for initial source water quality and following changes in water quality over time. These data, because of our controlled experimental design, may explain why recontamination has been reported in the literature as less prominent in areas or households with highly contaminated source waters. Our results also suggest that efforts to improve source water quality and sanitation remain important.