Isotope Hydrology in Pakistan. Instrumentation-Methodology-Applications

摘要

Isotope hydrology, including the development of related instrumentation, methodology of isotopic analysis for (2)H, (13)C, (15)N, (18)O and (34)S and applications in selected areas in Pakistan, are presented. Up-grading of a Varian Mat GD-150 mass spectrometer has improved the accuracy of analysis and through-put manifold. The development of two mass spectrometers, namely: a D/H mass spectrometer with automatic (3)H-compensation and a (34)S/(32)S mass spectrometer has been described. The fabrication of various sample preparation systems for (2)H, (13)C, (18)O and (34)S analyses on the mass spectrometer has also been presented. The use of above isotopic techniques in understanding and solving various hydrological problems of the country has been described. The studies have brought up some definite conclusions about the source of salinity, waterlogging and turnover times of various aquifers. The downward movement of soil moisture in an unsaturated zone has been studied in detail and some recommendations regarding delta of irrigation, presently in practice, have been made.