About 40 percent of the world’s population does not have access to latrines or other facilities for daily use.
It is also estimated that approximately 40 percent of all hospital beds in developing countries
are used by those suffering from water borne diseases
such as cholera, typhus, hepatitis A and diarrhea. Approximately 3000 children die each day of diarrhea.
http://waterinternational.org
It is also estimated that approximately 40 percent of all hospital beds in developing countries
are used by those suffering from water borne diseases
such as cholera, typhus, hepatitis A and diarrhea. Approximately 3000 children die each day of diarrhea.
http://waterinternational.org
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Effect of Safe Water on Diarrhea in ChildrenWhat would be the effect if contaminated water could be made safe for drinking by pasteurization or boiling? One estimate in the Philippines predicts that if families using moderately contaminated wells (100 E. coli per 100 ml) were able to use a high-quality water source, diarrhea among their children would be reduced by over 30%. If contaminated water could be made safe for drinking by boiling, why is boiling not uniformly practiced?
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Boiling isn’t Necessary in Killing Disease-causing MicrobesWorldwide, unsafe water is a major problem. An estimated one billion people do not have access to safe water. It is estimated that diarrhea diseases resulting from contaminated water kill about 2 million children and cause about 900 million episodes of illness each year. The majority of diseases in developing countries today are infectious diseases caused by bacteria, viruses, and other microbes which are shed in human feces and polluted water which people use for drinking, cooking or washing hands etc. When people drink the live microbes, they can multiply, cause disease, and can be shed in feces into water, continuing the cycle of disease transmission.
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Water Testing in Developing CountriesThe standard method of testing water for the presence of coliforms and E. coli requires trained personnel and a good laboratory facility or field unit which are usually not present in developing countries. Thus, water supplies are almost never tested.
In 1987, the Colilert MPN Test (CLT) was introduced as the first method which used a defined substrate technology to simultaneously detect coliforms and E. coli. The CLT comes as dry chemicals in test tubes containing two indicator nutrients: one for coliforms and one for E. coli. The CLT involves adding 10 ml of water to a tube, shaking to dissolve the chemicals, and incubating at body temperature for 24 hours. If no coliform bacteria are present, the water will remain clear. However, if one or more coliforms are present in the water, after 24 hours their growth will metabolize, and the water will change in color from clear to yellow (resembling urine). If E. coli is among the coliform bacteria present, it will metabolize and the tube will become fluoresce blue when a battery-operated, long-wave ultraviolet light shines on it, indicating a serious health hazard. |
Water Pasteurization Indicator
How can one determine if water has reached 149°F/65°C? In 1988, Dr. Fred Barrett (USDA, retired) developed the prototype for the Water Pasteurization Indicator (WAPI). In 1992, Dale Andreatta, a graduate engineering student at the University of California, Berkeley, developed the current WAPI. The WAPI is a polycarbonate tube, sealed at both ends, partially filled with a specialized wax which melts at 65°C. The WAPI is placed inside a water container with the wax at the top of the tube. A washer will keep the WAPI on the bottom of the container. When the wax melts and falls to the bottom of the WAPI, the water has reached pasteurization temperature, 149°F, even if the water has cooled by the time you check it. Remove WAPI from heat and allow the wax to solidify for accurate readings, about 15 minutes before reuse. Turnover and pull the wire through to the other end. The WAPI is now ready for the next use.
The WAPI could be useful immediately for people who currently boil water to make it safe to drink or in natural disasters. The WAPI will clearly indicate when a safe temperature has been reached and will save fuel which currently is being wasted by excessive heating. |
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For questions or comments contact Dr. Robert Metcalf, Ph.D. at [email protected]