[audio:http://www.wdde.org/wp-content/uploads/2014/12/GROUNDWATER2.mp3|titles= Delaware Public Media science reporter Eli Chen interviews UD geochemist Neil Sturchio.]
Scientists have developed a new technique for telling how old groundwater is. Authors of the study include University of Delaware geochemist Neil Sturchio, along with researchers from the International Atomic Energy Agency and Argonne National Laboratory.
The paper was published online in the journal Nature Geosciences Monday. The new technique uses Krypton-81, an isotope produced by cosmic rays from the Earth’s atmosphere. Existing techniques use helium and chlorine isotopes, which can distort the age of the water and make it appear older than it is.
Sturchio, chair of geological sciences at University of Delaware, says that determining the age of groundwater can better inform us about the availability of water resources, especially in dry arid places like California and Egypt.
“There are many places in the world where probably the only abundant source of water for drinking and agriculture and so forth is the groundwater. This is true in many desert areas. One of the difficult things to know about the groundwater is how long it’s been there, how much it’s being replenished,” Sturchio said.
Sturchio and his colleagues arrived at this new technique after fieldwork in Brazil led them to test an aquifer containing groundwater that turned out to be about 830,000 years old.