This is the VOA Special English Development Report.

Today we tell you about the LifeStrawwater-purifying device. Then learn about a wood-burning cookstove that scientists hope will reduce the loss of forests in poor countries.

The LifeStraw is a thick plastic tube 25 centimeters long. You place one end into water and drink from the other. The water passes through a series of filters to catch extremely small particles. Iodine¹ and active carbon are also used in the cleaning process. It all takes about eight minutes for one liter.

The maker² of the LifeStraw says it kills organisms that spread diarrhea, dysentery, typhoid and cholera³. The device filters most bacteria and parasites⁴. But it has limits, including against viruses. Also, it does not remove arsenic⁵ or other heavy metals from water.

The Vestergaard Frandsen Group, a Danish company with headquarters in Switzerland, invented the LifeStraw last year. The company makes disease-control textiles including malaria⁶ nets treated to kill mosquitoes.

The LifeStraw costs about three dollars. It can be worn on a string around the neck. It has a lifetime of up to 700 liters, or about one year. The first large shipments went to Pakistan after the earthquake last year.

The company notes that each day, worldwide, more than 6,000 children and adults die from unsafe drinking water.

Another problem in many poor areas is finding enough firewood to cook with. Forests can disappear as more and more trees are cut down.

Scientists have developed a cookstove that was tested in refugee camps in Darfur, Sudan. The scientists are from the Lawrence Berkeley National Laboratory and the University of California, Berkeley.

Two of them, Ashok Gadgil and Christina Galitsky, went to Darfur late last year. They found that many refugee families were missing meals for lack of fuel.

The light metal stove needs much less fuel than the traditional cooking methods used in the camps. This would mean less need for women to leave the camps to search for firewood and risk being attacked in violence-torn Darfur.

Since the visit, the researchers have improved the stove. Now they are trying to set up production. They estimate that the stoves could be built locally in Darfur for about fifteen dollars each. They say about 300,000 are needed. The hope is to begin producing 5,000 stoves by the end of the year.

And that's the VOA Special English Development Report, written by Jill Moss⁷. I'm Steve Ember.

water-purifying device : 水净化设备