The key objectives of establishing Isotope Hydrology Section of the Atomic Energy Authority (AEA) are,

Mr. Viraj Edirisinghe, Director
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Isotope Hydrology: Tools to unlock waters secrets

Water resources are being increasingly stressed by multiple factors, including growing population, grater food production, irrigated agriculture, energy production and climate variability and change. One billion people around the world currently have no access to safe drinking water and only about 15% of the worlds population enjoy relative abundance.

A key requirement for assuring adequate water supplies and their sustainable
management is to improve the assessment of water resources. Such assessments
are severely lacking in most of developing countries. The greatest proportion of
the earths available fresh water is located underground, and this vital resource is
often poorly understood and poorly managed

Only with precise information on the availability and renewability of water resources can country makes sound decisions about sustainable water resources management. Isotopes provide unique information about water resources characteristics in a cost efficient, accurate and easy-to-use way. Isotopes are waters fingerprints. They provide information on the age, origin and renewal rate of groundwater, its dynamics, as well as the vulnerability to source of pollution, salt water intrusion and climate change.

Further Reference

Analytical Capabilities

Isotope Hydrology Laboratory of the Atomic Energy Authority is equipped with following equipments for water isotope measurements and wet chemical analysis.

a. Liquid Water Isotope Analyzer-LWIA (Laser Mass Spectrometer) for stable
isotopes (18O and 2H) measurements in water

b. Liquid Scintillation Counter (LSC) for radioactive isotope (3H) measurements in water. This includes electrolysis enrichment of 3H in natural waters.

c. Spectrophotometers / Digital Titrators for wet chemical analysis (major ions) of
water and basic water quality measuring kits for field measurements of pH, EC, DO
etc in water.


Applications of Isotope Techniques in Water Management and Dam Safety

Isotope techniques allow rapid understanding of hydrological systems that may
otherwise require years or decades of monitoring. Therefore it is cost effective. In
some cases it is unique

Isotopes are commonly employed to investigate: 

  1. Identification of groundwater recharge sources
  2. Recharge areas
  3. Mixing of different water sources
  1. Identification of modern recharge
  2. Groundwater movement and residence time
  3. Infiltration rates in unsaturated zone
  4. Identification of paleowaters
  5. Delineation of protection zones
  1. Identification of pollution sources
  2. Origin of nitrates
  3. Origin of groundwater salinity
  4. Microbial denitrification processes
  5. Mixing of sea water
  1. Leakage /seepage problems
  2. Effect of dam reservoir on surrounding areas
  1. Source of thermal waters
  2.  Residence time
  3. Subsurface history (rock-water interaction, mixing with fresh water)
  4.  Estimation of reservoir temperature

Most commonly used isotopes are 2H1 ,3H1 ,18O8 ,13C6 ,14C6 , 15N7 and 34S16