Abstract
During the last years, a complete set of brines, groundwaters and surficial waters surveys was carried out in oilfields in order to determine the presumed oil born contribution to the groundwater pollution. The survey included the most important basins in Argentina and a wide variety of geological and hydrogeological conditions. Although conventional hydrogeochemistry played an initial role, the isotope tool has been the key for unravelling some delicate and doubtful cases. Most brines are very well characterized by their isotope composition and high salinity, leading to an easy recognition in the case of mixing. Besides the stable isotope composition of oxygen and hydrogen, tritium and Sr isotopes helped to model the interaction of production waters, groundwaters and surficial waters. As a matter of fact, and except for some old passives, the results showed that the improvement and change in water managing practices during the last decade avoided major problems. Despite this situation, the lack of knowledge on the new practices of oil industry and a high degree of incredulity from the people, limits the appreciation of this improvement to the courts and specialists. A thoroughful campaign to clarify the results, utility, confidence and limits of a multitracer approach is necessary to face the public concern in order to demonstrate that the oil activity can be environmentally friendly and that the water resources are a common heritage that will be preserved.
