March 21, 2001

GENEVA (AP) - A do-it-yourself technique of disinfecting water with sunlight and soft-drink bottles could save up to 2.5 million lives a year, the World Health Organization said Thursday.

In a campaign to reduce water-related deaths in developing countries, the United Nations health agency is promoting Solar Water Disinfection or SODIS.

Martin Wegelin, a researcher at the Swiss Institute for Environmental Science and Technology, said when transparent bottles are filled with water and placed horizontally on a flat surface for about five hours, the heat and ultraviolet rays of the sun kill illness-causing microorganisms in polluted water.

The method is even more effective when the bottom half of the bottle is painted black or placed on black-painted corrugated iron or plastic sheets, he said.

More than one billion people drink unsafe water, WHO said in a report on water and sanitation released to mark World Water Day. Some 3.4 billion people, mostly children, die every year from water-related diseases, which include malaria, diarrhea and guinea worm.

WHO urged the use of SODIS, chlorination and better hygiene as immediate means of improving people's water supply in developing countries.

Chlorination is another simple method that costs just a few cents a day, WHO said.

``Even in conditions of very poor sanitation and hygiene, where people are collecting whatever water is available for their household supply, if the water is chlorinated (it) is improved,'' said Mark Sobsey, professor of environmental microbiology at the University of North Carolina in Chapel Hill. ``And you can find statistically significant decreases in diarrhea disease.''

WHO said chlorine could be added to both home and city reservoirs and was essential in refugee camps.

The International Federation of the Red Cross and Red Crescent said it was redoubling its efforts to provide disaster victims with access to clean water and sanitation.

It has been deploying emergency water purification units to relief camps and provides 20 million liters (5.3 million gallons) of water per day to one million people, spending 50 million Swiss francs (dlrs 30 million) a year.