Abstract. In France, the mining and milling of uranium ore and the disposal of uranium mill tailings involved nearly 200 sites of very different nature. Being in charge of both the review of some remediation reports and the routine monitoring of the environment provides IRSN with selective data on most sites. The data collected by IRSN as well as those available from other data sources often remain incomplete therefore preventing IRSN from presenting a global view or answering some specific questions. In order to overcome this difficulty, it was decided, under the aegis of the Ministry of Ecology and Sustainable Development, that IRSN should develop a program of investigations organized in two parts: Part 1, called "State of knowledge " is aimed at assessing the amount of information available and at consolidating it into a user-friendly computerized database. The main goal is to identify the occurrence of significant enhanced radiological levels in the environment and to detect any lack of information concerning the various sites. This paper gives an overview of the information already collected. Part 2, called "specific studies" is aimed at fixing the gaps in the database by implementing new investigations on specific sites. It could lead to improvements in networks for the monitoring of radioactivity in the environment.

Dans son rapport remis aux ministres en 1999, le GRNC a indiqué la nécessité de mener des compléments d'études afin de combler certaines lacunes dans la connaissance de paramètres radiologiques. Le GRNC a également recommandé de prendre en compte des aspects autres que radiologiques. Suite a ces recommandations, les ministres de la Santé et de l'Environnement ont confié au GRNC une deuxième rnisîion portant sur l'étude des incertitudes associées aux résultats de la première mission, et la prise en compte des rejets chimiques. De plus, à la faveur de diverses études publiées récemment par I'IRSN, des informations sur des concentrations de radionucléides peu étudiés jwqu'alors ont été obtenues et des paramètres ont été précisés. Des informations totalement nouvelles ont été acquises comme celles sur le chlore-36. Dans le présent texte les apports scientifiques obtenus depuis la publication du rapport GRNC sont résumés. RÉSUMÉABSTRACT Updating of scientific data following the Nord-Cotentin Radioecology Group (GRNC) recommendations expressed in 1999.In its report submitted to the ministers in 1999, the GRNC indicated the need to carry out further studies sa that some gaps in the knowledge of radiological parameters are filled, and recommended ta take into acconnt aspects other than the radiological ones. Further ta these recommendations, the ministers of State of Health and Environment assigned the GRNC the responsihilitg of a second mission (study of uncertainties on the first mission results, and consideration of chemical releases). Then, about the radiological data used, thanks to various studies recently puhlished hy the IRSN, information concerning radionuclide concentrations, not much studied until then, has heen ohtained and parameters have been specified.Completely new information has heen acquired as chlorine-36 information. In the present text are summarized the scientific contributions ohtained since the GRNC report publication.i IRSN. B.P. IO. 50130 Cherhourg~OcteviIIr. France.