Isotope fingerprinting of Ganga Basin groundwater : A presentation by Prof P.S.Dutta of IARI

One of the most grippping and intensly scientific presentation at WHSC has been this one, by Prof. P.S. Datta of the Nuclear Research Laboratory, IARI. Groundwater can be studied in its entirety by profiling the isotopes of water. His talk on Isotope fingerprinting of Ganga Basin groundwater to protect it from vulnerability to depletion and pollution had gripping scientific findings, which could advance our understanding of the diverse phenomena of hydrological cycle.

 Prof. P.S. Datta

The concerns of resource managers, according to Prof. Datta are :

• 
  Search adequate quantity of good quality GW.
• Assess quantity and recharge characteristics.
• Evaluate water quality and degradation causes.
• Identify GW flow pathways of inter-mixing
• Protect water from depletion and degradation.
• Evolve a Partnership/Participatory approach.

From the day's line up of speakers, we have people presenting on all the above concerns. From the above list , evaluating water quality, its degradation causes and identifying ground water flow pathways of inter-mixing can be addressed by isotopic techniques.

The concept is based on the fact that water acquires specific signatures, (in the form of isotopes) and so referred to as "isotopic fingerprints" when water changes its phase (like evaporation) or when different masses of water mixes together. These isotopes thus formed are the signatures which could reveal the entire course of events about the water.

And hence, it was appropriately said that, "Water memorises its origin and path". The potential of this technique is in determining:

• Temporal & spatial variations in the environmental isotope composition of rainfall, river and local groundwater.
• Rainwater Harvesting: To locate the altitude of recharge & understand the recharge process
• Modelling techniques for safe abstraction of groundwater
• Identify sources, mechanisms, extent of salinization/pollution of GW and prediction of the fate of contaminants in groundwaters.

For detailed explaination and experimental data, I highly suggest to download the presentation by Prof. Datta from here (pdf, 2.65 mb)

This novel approach, in applying nuclear research to ground water studies is the basis of the (now famous) ground water depletion images of north India published by GRACE, NASA group. See the images on this post.