Isotope and tracer techniques applied to groundwater hydrology: The experience of CDTN/CNEN, Brazil

Studies in surface waters and in sedimentology with the application of radioactive tracers techniques are soundly established, and the group of researchers at CDTN/CNEN, which started in the early sixties, is now very qualified. Nevertheless, investigations in groundwater hydrology, which were given considerable attention in the past, were curtailed and remained restrained for a long time. Restarting activities in this area is a great concern of the group, prompted by water scarcity and vulnerability of water resources to pollution in several regions of the country. The main goal is to upgrade a team of specialists able to apply isotopic and nuclear tools in the study of hydrologic processes in the water cycle, particularly aimed at the comprehension of groundwater dynamics and its interactions with atmosphere and surface waters. Special attention should be given to natural or semi-natural tracer methods based upon the use of environmental (both stable and radioactive) isotopes