A highly poisonous substance, arsenic finds its way into drinking water in some parts of the world due to geological conditions or mining activity. Over 100 million people are at risk, especially in Southeast Asia, where rapid population growth has made it necessary to tap groundwater from deeper levels in recent years. Chronic arsenic poisoning can severely damage the skin, kidneys and liver, and can even lead to cancer. There are also certain regions in Germany where ore mining has contaminated the groundwater with arsenic. In Southeast Asia, local variations in arsenic levels are so great that ideally every well should be tested - which was virtually impossible up to now because it required complex laboratory tests that had to be carried out by experts.

Teams of scientists led by Professor Hauke Harms, Dr Mona Wells and Professor Jan Roelof van der Meer have come up with a new method that indicates arsenic levels in water reliably within just two hours (incubation period). Patented under the name ARSOlux®, the new test is easy enough for laypeople to use correctly. The basic principle behind the test was developed at the University of Lausanne in Switzerland by Professor van der Meer and his team. Based on microbiological findings, it uses bacteria as so-called "bioreporters". Through genetic engineering, bacteria strains are enhanced with "reporter genes" that cause the cells to glow when exposed to arsenic. The method was systematically refined over the past several years by Professor Harms and his team of researchers in the Department of Environmental Microbiology at the Helmholtz Centre for Environmental Research. The genetically modified bacteria are freeze-dried and stored in test tubes until they are needed. For the actual test, the test tube is filled with water and inserted into a small device that measures how much light is emitted by the bacteria. This luminescence is a measure for the arsenic concentration in the water sample. Using mathematical methods, Dr Mona Wells of the UFZ has managed to improve the reliability and precision of the test to the point that it is actually more accurate than simple chemical analyses.

At only about $1.50 per test, the ARSOlux® method is significantly less expensive than chemical lab tests, and experts say that it also delivers more conclusive results. Unlike a purely chemical analysis, the bioreporter bacteria show to what extent living organisms would absorb certain chemicals, allowing statements to be made in respect to bioavailability and the health risk posed by substances present in water.

Over the past few years, scientists have tested the method in campaigns carried out in Vietnam and Bangladesh, and have shown that the ARSOlux® test also delivers reliable results under reallife conditions. With financial support from the Helmholtz Enterprise Fund (HEF), the scientists have developed the patented method to the point that it is ready to be marketed and plan to found a company that will manufacture and sell the measuring devices and test kits beginning in 2011. The devices could initially be employed in mobile clinics that drive from village to village in Bangladesh.

Other potential customers would be international aid organisations, which could use the test prior to drilling wells to determine if the well would supply safe drinking water.

About the award recipients: