Three glasses of water from around the world - Libya, Australia and Vienna - sat on a table waiting for the ultimate "taste test". They all looked identical. They all smelled alike. They all originated from local rain. The big difference was, some of it fell recently and some thousands of years ago.
So how did the water taste?
Wet. The taste between the 140 thousand year old water from Down Under and five year old tap water from Vienna was not discernable to this connoisseur - or the dozens of water experts who tried and were fooled by Mother Nature at the IAEA General Conference water exhibit. Admittedly perhaps the Australian water was a little saltier.
Revealing Water´s Mysteries Where Taste Buds Fail
The exhibit showed that taste buds won´t tell you much about the age of water but chemical elements called isotopes can. Knowing the age of water reveals how long it has been underground. The younger it is, the more communities can pump away with the confidence that rainfall is replenishing their water supply.
It´s an opposite story for the 140 thousand year water from the Great Artesian Basin in outback Australia, and the 25 thousand year old water from the Kufra aquifer in Libya. These ancient waters are limited resources. By knowing the age of water countries can better manage and sustain their freshwater sources. It´s key information that scientists are sharing through IAEA-supported projects around the world.
If you look at the Middle East, everywhere you are using old water, says Pradeep Aggarwal, who heads the IAEA isotope hydrology unit. "It is rainfall from 10,000 maybe 100,000 years ago. So countries have to understand there's a limit to how long this will last."
The natural isotopes of the water molecule, hydrogen (namely deuterium) and oxygen (oxygen-18), as well as carbon isotopes are studied using techniques collectively known as isotope hydrology. Cheap and reliable, they tell scientists how much water is available, how often it is replenished, where it comes from (and if it crosses national borders), and if there is any more to be found.
That´s vital information in a world where more than a billion people lack access to safe drinking water, which each year kills some 15 million children under the age of five.
Scientists at the IAEA´s Isotope Hydrology programme are further advancing these investigative tools and extending them to scientists around the world. As a recent article in the IAEA Bulletin explains, more than 80 projects run in some 50 countries including India, Bangladesh, Ethiopia and Uganda.
IAEA Deputy Director General Mr. Werner Burkart points out that the lack of freshwater availability is not the only cause of looming water scarcity. "The global water crisis is also a crisis of governance," he says, as countries work with the IAEA to improve their management of precious groundwater sources.
Or as Mahatma Gandhi aptly put it many years ago, "There is enough water for human need, but not enough for human greed".
Isotope hydrology offers a way to better manage the planet´s water resources and help prevent future crisis.