Simple arsenic water test could save lives

A simple test devised by students at Edinburgh University could save lives by alerting villagers in developing countries to the presence of arsenic in water.

Up to 100m people around the world suffer arsenic poisoning each year after drinking contaminated water, and around a million develop cancers, mostly of the skin, as a result, according to the World Health Organisation.

Detecting arsenic in village wells has so far required an expensive and sophisticated laboratory tests often inaccessible in developing countries, where people are most likely to drink untreated water.

The new test, devised by nine Edinburgh students supervised by faculty members, uses a colour-coded system whereby the water turns red in case of high contamination, remains the same if some arsenic present or blue if there is none.

It uses a modified version of e-coli bacteria which release acid in the presence of arsenic to affect the colour change, and would cost around 50p to manufacture. The only field tests available so far could only detect high levels of arsenic, a chemical that can penetrate into groundwater naturally as it flows through arsenic-rich rock.

The device could bring relief to countries like Bangladesh, where up to 35 million people drink arsenic-polluted water from wells. Ironically, programmes aimed at providing "safe" drinking water have added to the problem. While most drinking water in Bangladesh used to be collected from ponds and rivers, a drive to fight cholera and other water-borne diseases led to an extensive well-drilling programme, with the unexpected side effect of exposing people to arsenic-contaminated groundwater.

Alistair Elfick of the University of Edinburgh's School of Engineering and Electronics, one of the team who devised the test, said: "One of the problems is that while a village may have a number of wells, not all of them will be contaminated. The levels of contamination in each of the wells also changes throughout the year.

"Instead of an expert having to come out to test the arsenic levels, people living in the villages can use our simple colour-coded system and repeat the test at regular intervals to monitor any changes in contamination.

"As well as not needing a field expert to carry out the test, our device is also much more sensitive than the one specialists currently use, which does not detect arsenic levels to WHO standards."

Edinburgh University has said it is looking for funding to develop the method.

Goska Romanowicz



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