PUT that drill away. Running electric currents through the earth can map salt contamination in groundwater supplies just as effectively as drilling boreholes.
The technique could provide a much faster way of monitoring groundwater in parched regions of the world such as the Middle East, where supplies can become contaminated by sea water seeping into inland aquifers.
A team led by Mohamed Khalil of Cairo University in Egypt mapped groundwater in the Sinai Peninsula between the Mediterranean and Red seas. They ran currents between electrodes in the ground and looked for variations that reveal fresh or salty water, since saltwater…
