Retired scientist from the Algiers Nuclear Reseearch Centre where I specialised in Isotope Hydrology and Radiochronology. During my early career first decade, I contributed to the building and the developement of a laboratory devoted to the use of both stable and environmental radioactive tracers in water and soil science. The remaining years I was commited to use the aforementionned tools (as a team member then as a leader) in studies addressing groundwater and environmental issues throughout my country but mainly in the Sahara desert. This was implemented in the framework of national (provision of services) and international co-operation projects (overwhelmingly under the auspices of the IAEA).