Acknowledgements
The work reported here is carried out under the aegis of a National Programme on Isotope Fingerprinting of Waters of India (IWIN) which was initially funded jointly by the Department of Science and Technology (DST), Government of India, vide Grant No. IR/S4/ESF-05/2004, and the Physical Research Laboratory (PRL), a Unit under the Department of Space, Government of India. The IWIN National Programme is currently sustained exclusively by the PRL.