| Following the Water: A Controlled Study of Drinking Water Storage in Northern Coastal Ecuador Karen Levy,1 Kara L. Nelson,2 Alan Hubbard,3 and Joseph N.S. Eisenberg4 1Department of Environmental Science, Policy, and Management, 2Department of Civil and Environmental Engineering, and 3School of Public Health, Division of Biostatistics, University of California, Berkeley, California, USA; 4School of Public Health, Department of Epidemiology, University of Michigan, Ann Arbor, Michigan, USA 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. Key words: diarrhea, drinking water quality, Ecuador, microbial contamination, point of use, recontamination, waterborne disease. Environ Health Perspect 116:1533–1540 (2008) . doi:10.1289/ehp.11296 available via http://dx.doi.org/ [Online 7 July 2008]
Address correspondence to K. Levy, University of Michigan, School of Public Health, Department of Epidemiology, 109 Observatory St., Ann Arbor, MI 48109. Fax: (253) 498-4617. E-mail: karenlev@umich.edu We thank D. Tenorio, G. Hurtado, M. Renteria, C. Ortiz, S. Tiwari, O. Solberg, S. Bates, W. Cevallos, K. Ponce, and other members of the Ecologia, Desarrollo, Salud, y Sociedad (EcoDeSS) team for their help in the field. This work was supported by the University of California Pacific Rim Research Program and the National Institutes of Allergy and Infectious Diseases (R01AI050038) . The authors declare they have no competing financial interests. Received 28 January 2008 ; accepted 3 July 2008.
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