Safe Drinking Water

Background

            Drinking water that has been contaminated by fecal-matter microorganisms is a major risk factor for diarrheal diseases.  (When feces get into drinking water, many more people get diarrheal diseases.  In the developing world, many children die of diarrheal diseases)  (Ricks et al 1992, Swerdlow et al 1992, Weber et al 1994, Mujica et al 1994, Cardenas et al 1992, Marlines et al 1993)  A meta-analysis by Fewtrell suggests Point of Use interventions are effective interventions. (2005)

Recomendations

Evidence

Narrow Mouthed Storage Vessels and Disinfection

Contamination of household drinking water stored in containers increases diarrheal disease. (Han et al 1987)  Multiple studies have shown that when water is stored in vessels in a household, using narrow mouthed water vessels reduces contamination of the stored supply.  (Deb et. al., 1986, Mintz et al. 1995, Quick et al, 1996)

• Some current interventions in Latin America are showing promise involving the design of effective water storage containers and proper disinfectants.
• Where the development and maintenance of piped water systems would be too expensive (between $100-150 per person served), proper water storage vessels would only cost between $1.50-4.00 annually per family of five.
• Projects using storage vessels are taking place in Bolivia, Colombia, the Dominican Republic, Ecuador, Nicaragua, and Guatemala are proving to be possible and feasible to help reduce diarrhea in these areas.
• Storage vessels should have a 10 to 30 liter capacity, be made of a durable translucent, lightweight plastic, have a small opening (between a 6 and 7.5 cm diameter) at the top to discourage hand contamination but still allow proper filling, a screw-on lid, a device to measure disinfectant, a faucet that will allow water to flow out at one liter in 15 seconds, and a small air-inlet valve for water displacement purposes. Also provided should be instructions on how to use and clean the container and a certificate of safety from the Ministry of Health or other authority figure.
• The disinfection provided for use should be reliable and effective under a variety of conditions, be added in enough quantity to allow for residual, not be toxic, have a simple, rapid, and accurate test for the residual levels (like the DPD test at 10 cents per test), have a long shelf life, and a low-cost.

This article promotes the use of small-mouthed storage vessels to both store and treat water on a household basis. The vessels are realistic in price, between $1.50-4.00 annually per family of five, and are proving to be effective in many countries. The project in Bolivia has decreased the incidence of diarrhea by 44%, especially in children. The Nicaragua project shows a 50% decrease in diarrhea and the Colombia study has about a 60% reduction from this and other accompanying interventions. All of the projects listed in this analysis included an education component, which was found to be essential. The cost-benefit analysis of the Bolivia study showed that 600 cases of diarrhea, 100 hospitalizations, and 5 deaths were prevented during a three year period. Spending four dollars for each person to have a container could have a great economic impact on that communities economics. Currently, organizations involved in this type of intervention include PAHO, CDC, Germany’s GTZ, and Italy’s CPC are carrying out demonstrations of this intervention in Bolivia, Columbia, Cuba, The Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, Panama, and Peru.

Water-filters

• Two randomized control studies show that a ceramic water filter are very effective in preventing diarrhea in both Bolivia and Colombia.
• The study in Bolivia showed a 100% of the households that used the filters were free of coliforms, but only 15.5% of the control households were coliform free. The study also showed a 70% reduction in diarrheal disease risk in all the people of the intervention group and 83% for children under 5 in the intervention group.
• Filters were made of two 15 liter clear plastic buckets (made locally), two Katadyn 240mm ceramic filter elements, and a metal dispensing valve.
• The Katadyn filters have pore size of 0.2 µ, are impregnated with silver for bacteriostasis, each candle can treat up to 50,000 liters of water depending on frequency of cleaning, and can produce up to 1.5 liters/hour of filtered water depending on turbidity.
• Instruction on filling, cleaning, and using the filter were given at a community meeting.
• Cost for one unit was just under $25.00, but the participants reported that they would not pay this much for a unit like the one tested.
• The experiment was replicated in Colombia, but the results, while still significant, showed a lower coliform and diarrhea reduction than the test in Bolivia.
• Clasen, Thomas F. et. Al. “Reducing Diarrhea Through the Use of Household Based Ceramic Water Filters: A Randomized, Controlled Trial in Rural Bolivia.” The American Society of Tropical Medicine and Hygiene. Vol. 70(6), 2004, pp. 651-657
• Clasen, Thomas F. et. Al. “Household-based Ceramic Water Filters for the Prevention of Diarrhea: A Randomized, Controlled Trial of a Pilot Program in Colombia.” Am. J. Trop. Med. Hygiene., 73(4), 2005, pp. 790-795

• Point-of-use water treatment filters along with adequate storage measures will reduce the microbiological load and contamination in home drinking water.
• Multiple randomized control trials have shown a greatly reduced microorganism count in water that was put through a filter.
• Statistical reductions have been between 20 and 30 percent reduced diarrhea incidence and reduced mortality rates in correlation with the reduction in microorganism count from these filters.

These studies provided evidence that the Katadyn ceramic style water filters could provide a relatively low-cost and effective method of reducing coliform and diarrhea incidence in Latin America. And evidence from multiple studies have made the connection between microorganism count and diarrhea incidence. Proper education on the maintenance and use for these filters is essential, however, for continued reductions. The lessened results in Colombia may be an indicator of local culture differences or perhaps a gap in the educational accuracy of the program.

Disinfection

The use of a disinfectant such as a solution of calcium or sodium hypochlorite can be a safe, cost-effective way of improving water quality that does not require excessive training.  Many interventions in rural areas use a standardized size of container and dilution of disinfectant to simplify disinfection dosing instructions. 
Many household bleaches are 5% sodium hypochlorite, and therefore many interventions use this widely available solution.  Care must be taken to read the ingredients carefully because not all bleaches are only 5% hypochlorite in aqueous solution. 
Other interventions use calcium hypochlorite produced locally with technology at an approximate cost of $.25/family/year.  (Mintz et al 1995, Wilt & Reiff 1993)

Behavioral Support

Motivational interviewing may be more effective than traditional forms of health education.  Motivation interviewing is based on decision making theory and motivational psychology (Miller and Rollnick, 1991)

• Sustained behavioral change may be most challenging in the poorest populations. They may lack the necessary resources to keep the changes after the initial intervention is over, especially for point-of-use water filtration and disinfection systems.
• Community-based interventions may be needed to stimulate demand for sanitation services or hygiene education programs.
• Maternity clinics and schools may be effective platforms for distribution programs like soap distribution, hand-washing technology, and education of mothers and children on the importance of hand-washing after using the bathroom.
• More research is needed to establish what the best education and intervention methods are to establish long-term behavior change within developing nations of Latin America.

References

Narrow Mouthed Storage Vessels and Disinfection

Water Filters

Zwane, A.P. & Kremer, M. What Works in Fighting Diarrheal Diseases in Developing Countries? A Critical Review. World Bank Reserve Obs,.2007 (0), lkm002v1-24.

Disinfection

Zwane, A.P. & Kremer, M. What Works in Fighting Diarrheal Diseases in Developing Countries? A Critical Review. World Bank Reserve Obs,.2007 (0), lkm002v1-24.