In many regions people rely heavily on groundwater and these resources are under threat. Questions like: How long has the water been in the ground? How fast and in which direction is it flowing? And, most important, at what rate is it being replenished from above? need to be answered. The Water Research Initiative, a joint project of UChicago, Argonne National Laboratory, and Ben-Gurion University of the Negev in Israel are trying to help answer these questions by studying water at atomic level. By extracting the gas from a sample of groundwater and measuring the amount of krypton 81 in it, scientists can determine with considerable accuracy how long the water has been in the ground. Read more at the University of Chicago's website.