The contamination of groundwater by arsenic is a huge problem in some parts of the world, such as Bangladesh and West Bengal. So Columbia University in New York has devised a pocket-sized meter that can measure levels of the toxic contaminant (W0 2004/019004). The aim is to give villagers a quick and easy way to check whether they are using safe wells.
To use the device, a villager squirts two identical water samples into two chambers in a disposable cartridge that is inserted into the meter. In one chamber the sample is oxidised with potassium iodate to produce arsenates…
