Narrow-mouthed water storage vessels and in situ chlorination in a Bolivian community: a simple method to improve drinking water quality
Quick R, Venczel L, Gonzalez O, Mintz E, Highsmith A, Espada A, Damiani E, Bean N, De Hannover R, Tauxe R
Abstract. Epidemiologic investigations of the Latin America cholera epidemic have repeatedly implicated untreated drinking water and water touched by hands during storage as important vehicles for disease transmission. To prevent such transmission, we provided a new narrow-mouthed, plastic, water storage vessel and 5% calcium hypochlorite solution for home disinfection of stored water to a Bolivian Aymara Indian community at risk for cholera. We evaluated acceptance of this intervention and its effect on water quality. Each of 42 families in the study obtained water from a household well; fecal coliform bacteria were found in water from 39 (93%) of 42 wells and 33 (79%) of 42 usual water storage vessels. One group of families received the special vessels and chlorine (group A), a second received only the special vessels (group B), and a third served as a control group (group C). Water samples collected every three weeks from group A special vessels had lower geometric mean fecal coliform colony counts (P < 0.0001) and lower geometric mean Escherichia coil colony counts (P < 0.0001) than water from group B or C vessels. Adequate levels of free chlorine persisted in these vessels for at least 5 hr. The special vessels and chlorine solution were well accepted and continued to be used for at least six months. Use of the vessel and chlorine solution produced drinking water from nonpotable sources that met World Health Organization standards for microbiologic quality. The cholera epidemic that began in Peru in January 1991 and swept through Latin America, causing more than 1.000,000 reported cases and 10.000 deaths, highlighted serious deficiencies in water quality and sanitation in this region. Investigations of cholera outbreaks in Latin America have implicated the consumption of fecally contaminated surface and municipal water sources as a major risk factor for disease transmission.1-5 In one investigation, cholera transmission was specifically associated with domestically contaminated water stored in open, widemouthed containers. The cost of providing potable water to each household and sewage treatment to each community in Latin America has been estimated at $200 billion, and these improvements would take at least 12 years to implement (de Macedo CG, Pan American Health Organization, unpublished data). This definitive approach to cholera prevention is not currently feasible. There is an urgent need for preventive measures that are effective, inexpensive, and easily disseminated and implemented. In November 1992, we initiated a pilot project in El Alto, Bolivia, to determine the feasibility of introducing a new intervention into a community at risk for cholera: calcium hypochlorite solution (a form of chlorine) for disinfection of drinking water stored in the home, and specially designed, plastic, narrow-mouthed, lidded, 20-liter water storage vessels to prevent recontamination of treated drinking water during storage.

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