The Swiss Federal Institute for Environmental Science and Technology (EAWAG) and the Department of Microbiology at the University of Lausanne, Switzerland, which developed the test, are now looking for laboratories in South Asian countries to develop the test on a larger scale.

The developers estimate that the test, Biosensor which is available in the shape of a paper strap, could find its way into the market at a price between Tk 1-2 if produced on a large scale.

"It is an easy way by which local people can test their water wells on the spot to find out whether or not the water is safe," explains Professor Jan Roelof van der Meer from the University of Lausanne, responsible for the project. The Swiss Agency for Development and Cooperation and EAWAG are jointly funding the project.

Biosensor is made of a paper strap containing bacteria and arsenic in water causes the paper strap to change colour. When held in the water for about an hour, the intensity of colour change will show people immediately how high the concentration of arsenic is.

"It is an alternative for people in the remote areas where there are no laboratories available to test water safety," Meer adds.

The International Centre for Diarrhoeal Diseases and Research, Bangladesh (ICDDR, B) in Dhaka estimates that almost 30 million people in Bangladesh are exposed to dangerous levels of arsenic in their drinking water.

Over the last two decades, tube well water has been heavily promoted and developed in Bangladesh as a safe and environmentally acceptable alternative to microbiologically unsafe untreated surface water.

In the mid-1990s, the crisis emerged into broad public awareness. The origin of the arsenic pollution is geological in this case; arsenic is released to ground water under naturally occurring aquifer conditions.

The EAWAG and the University of Lausanne are so far working together with the Hanoi Institute in Vietnam. But the researchers would like to do more. "We are now facing a lack of finances in order to do field tests with Biosensor on a large scale," said Meer. At least, $150,000 would be needed.

According to the government, only 71 percent of the population has access to safe drinking water, since the arsenic problem crept up. But some scientists put the figure at less than 40 percent.

Already, more than one million people are suffering from health problems in Bangladesh because of the exposure to arsenic water. "Our test could make sure at a low cost that no-one is exposed to this life-threatening danger," Meer notes.