A safe solution: disinfection at home could provide Africa with cheap and abundant potable water

Science News,  March 1, 2003  by Ben Harder

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Ogongo, Kenya -- To the crowd's delight, the dancer wiggles his hips and flails his arms. His bulky, blue costume--an oversized embodiment of a bottle of chlorine solution--lurches comically. In step with a drum-and-guitar accompaniment, other performers masquerade as a water jug and caricatures of a man and a woman. Among the audience are Kenyan health workers, local farmers and their children, and two conspicuous white foreigners, medical epidemiologist Rob Quick and me.

Sweating and thirsty from the equatorial heat, I take the beverage an event organizer offers me. I'm glad to see that it's a soft drink. Quick has told me more than I want to know about the microbes that flourish in the local water.

A few minutes later, in the grassy clearing that serves as their stage, two actresses face off against three actors who have identified themselves as Typhoid, Cholera, and Amoeba. As the men grimace menacingly, the women recite tips about how to disinfect drinking water. The skit ends when the pathogen impersonators collapse under the women's verbal onslaught.

The drama played out in this western Kenyan village may smack of comedy, but the performers are engaged in a deadly serious public health campaign. The chlorine-based system they're promoting for water treatment could save millions of lives, some researchers say. In areas where the inexpensive, low-tech method has been introduced, it has cut diarrhea rates and won adherents, and it's now poised for a rapid deployment throughout Kenya.

With epidemiological evidence that supports the system's effectiveness, its promoters are working to deliver it to many people. As a journalism fellow working with the CDC Foundation and sponsored by the John S. and James L. Knight Foundation, I saw that effort in action when I followed Quick last September some 10,000 miles from his headquarters at the Centers for Disease Control and Prevention (CDC) in Atlanta.

LET THEM DRINK COKE For many Kenyans, and for much of the world's population, microbe-contaminated drinking water is a fact of life and, all too often, death. Recent calculations suggest that waterborne infectious organisms cause billions of diarrhea illnesses worldwide and more than 2 million diarrhea-related deaths each year. Infants and children are the hardest hit. The World Health Organization estimates that most of these deaths could be prevented if all people had access to safe drinking water and adequate sanitation.

However, the international organization also figures that approximately 1.1 billion people around the globe rely on ponds, streams, and other exposed and untreated sources for their drinking water. Despite concerted international efforts to expand access to wells and municipal waterworks, the number of people drinking water from so-called unimproved sources has remained more or less the same since 1990.

In September 2000, the United Nations set a 15-year goal of providing improved water supplies to half the people who currently lack them. That ambitious target mandates that, not allowing for population growth, about 125,000 new people gain access to safe water every day between now and 2015, Quick notes.

That would solve only part of the problem. In addition to the people who use an unimproved water source, 1 billion or more with access to pumps, wells, or municipal water works also frequently drink microbe-contaminated water, estimates Steve Luby, Quick's colleague at the CDC. Many households in the developing world draw contaminated water from poorly maintained pipelines. Furthermore, Luby says, such municipal systems and other communal sources of running water often work only intermittently, so families store water in the home. The CDC has found that water can become contaminated during storage, especially when its container is a bucket or other wide-mouthed vessel into which people dip hands or cups.

"The ultimate good would be for everyone to be able to open a tap in their house and have clean water come out," says Sally Cowal, a vice president of Population Services International (PSI), a Washington, D.C.-based nonprofit group. It will take years to fund and build the required infrastructure in many parts of the world, she notes.

QUICK FIX That's why Quick and his colleagues are championing a low-tech, interim solution to enhance drinking-water quality--one that can be marketed cheaply on a large scale. Their approach, referred to as the Safe Water System (SWS), emphasizes disinfection at the places where water is consumed. The two physical components of SWS are a chlorine-based disinfection solution and a storage container that prevents recontamination.

The concept behind SWS began to take shape during a series of CDC missions in the early 1990s in response to outbreaks of cholera and other diarrheal diseases in Latin America and Africa. Quick, then a newcomer to the CDC, and his fellow disease investigators observed that people who used water-storage vessels with wide mouths were more likely to get diarrhea than neighbors using narrow-mouthed containers were. Quite simply, people were more likely to stick hands or potentially contaminated objects into containers with larger openings.