Six quintillion gallons of groundwater present in upper earth’s crust

More than two billion people in the world are dependent on groundwater from drinking purposes every day. It is even pumped out to grow crops and plays a vital environmental role. Lately, a research has been done to have an idea of how much groundwater is there and what is its age and how long it has been underground.

The research paper published in Nature Geoscience has unveiled that there are six quintillion gallons of groundwater in the upper 1.2 miles of the Earth's crust. Study’s lead researcher Tom Gleeson, a hydrogeologist at the University of Victoria in Canada said, “Our maps and estimates show where the groundwater is quickly being renewed and where it is old and stagnant and non-renewable”.

In order to know this much amount of water is present beneath earth, the researchers have used computer models in which 40,000 different measurements were carried out on how much water can be stored in different rocks across the planet.

To know about the age of groundwater, the researchers have looked into how much tritium is present in groundwater across the globe. Tritium is a radioactive isotope of hydrogen that has increased in rain water around five decades back.

After reviewing the scientific literature, the researchers came to know about 3,700 tritium measurements of groundwater from 55 nations. From this, it was found that around 5.6% of groundwater is less than 50 years old.