Aerosol deposition and origin in French mountains estimated with soil inventories of 210Pb and artificial radionuclides

Radionuclide inventories were measured in soils from different French mountainous areas: Chaîne des Puys (Massif Central), Eastern Corsica, Jura, Montagne Noire, Savoie, Vosges and Rhine Valley. 210Pb soil inventories were used to estimate long-term (>75 yr) deposition of submicron aerosols. Whereas 210Pb total deposition is explained partly by wet deposition, as demonstrated by increase of 210Pb inventory with annual rainfall; a part of 210Pb in the soils of higher altitude is caused by orographic depositions. Using measurements of radionuclides coming from nuclear aerial weapon tests (137Cs and Pu isotopes), we were able to estimate the origin of aerosols deposited in high-altitude sites and to confirm the importance of occult deposition and feeder–seeder mechanism. Using a simple mass balance model, we estimate that occult deposition and feeder–seeder mechanisms account to more than 50% of total deposition of 210Pb and associated submicron aerosols in French altitude sites

Deposition of artificial radionuclides from atmospheric Nuclear Weapon Tests estimated by soil inventories in French areas low-impacted by Chernobyl

Soil inventories of anthropogenic radionuclides were investigated in altitudinal transects in 2 French regions, Savoie and Montagne Noire. Rain was negligible in these 2 areas the days after the Chernobyl accident. Thus anthropogenic radionuclides are coming hypothetically only from Global Fallout following Atmospheric Nuclear Weapon Tests. This is confirmed by the isotopic signatures (238Pu/239þ240Pu; 137Cs/239þ240Pu; and 241Am/239þ240Pu) close to Global Fallout value. In Savoie, a peat core age-dated by 210Pbex confirmed that the main part of deposition of anthropogenic radionuclides occurred during the late sixties and the early seventies. In agreement with previous studies, the anthropogenic radionuclide inventories are well correlated with the annual precipitations. However, this is the first time that a study investigates such a large panel of annual precipitation and therefore of anthropogenic radionuclide deposition. It seems that at high-altitude sites, deposition of artificial radionuclides was higher possibly due to orographic precipitations

Detailed plan for the COMET WP3 initial research activity - list of research projects and goals, participants and timing

Detailed plan for the COMET Work Package (WP) 3

COMET deliverable (D-No. 1.5). COMET project final report: advancement in science, integration and sustainability of European radioecology

The EC FP7 COMET (Coordination and iMplementation of a pan-European instrument for radioecology) was funded to strengthen the pan-European research initiative on the impact of radiation on man and the environment by facilitating the integration of radioecology research and development

Répartition du plutonium et de l'americium dans l'environnement terrestre de la basse vallée du Rhone

Ce travail fait le bilan des stocks et des flux d'actinides dans l'écosystème terrestre de la basse vallée du Rhône. Les radionucléides 238Pu, 239+240Pu et 241Am sont omniprésents dans l'environnement du fait des retombées des essais atmosphériques d'armes nucléaires pratiqués entre 1945 et 1980 et de la désintégration du générateur d'un satellite américain dans la haute atmosphère en 1964. Les activités d'actinides liées à cette source globale sont estimées à 770 GBq sur une zone de 11000 km2 dans la partie terminale de bassin rhodanien. Ces dépôts, caractérisés par un faible rapport d'activités 238Pu/239+240Pu se sont répartis de façon relativement homogène. Dans la basse vallée du Rhône, certaines zones de l'environnement terrestre se distinguent par des activités surfaciques et des rapports d'activités plus élevés attribuables aux rejets du centre nucléaire de Marcoule. Sur une surface d'environ 30 km2 autour de cette installation, les activités d'actinides ajoutées sont estimées à près de 2,8 GBq. Les mesures et la modélisation s'accordent pour attribuer ces activités aux rejets atmosphériques anciens du site.AIX-MARSEILLE3-BU Sc.St Jérô (130552102) / SudocSudocFranceF

Monitoring of radioactivity along the French Mediterranean coast

International audienceSince the beginning of the 90’s, IRSN realised sampling of bioindicators (mullet fishes and mussels) along the French Mediterranean coastline in order to (1) establish reference levels and (2) highlight the possible influence of nuclear installation/activities on the marine environment. Gamma analyses, conducted sincethe beginning, are now completed by measurements of 3H(OBT), 14C, 241Am, 238Pu, 239+240Pu and allow toobtain a new overview of the radiological influence of human activities on this environment. Additionalmeasurements of 210Po in fishes and mussels also used to best estimated the dose by ingestion for seafoodconsumers.Historical and spatial analyses are presented, and the influence of the different nuclear site/activities isinvestigate

Modélisation hydro-sédimentaire de la rade de Toulon : application à l’étude de la dispersion de radionucléides

L’objectif de ce travail est mettre en place un modèle hydro-sédimentaire de dispersion des radionucléides, comme outil d’aide à la décision suite à une hypothétique contamination marine accidentelle. Appliqué à la Rade de Toulon, il utilise le modèle MARS-3D pour l’étude hydrodynamique et le module MIXSED pour la dynamique des différentes classes de sédiments. Les cas d’application présentés concernent le césium et le plutonium, qui ont des affinités très différentes avec les sédiments fins. Les simulations de rejet, effectuées en fond de baie, montrent une variabilité saisonnière marquée, due aux conditions météorologiques typiques, mais aussi aux conditions de débit et de charge sédimentaire associée du fleuve Las, qui se jette dans la Rade. Ainsi, les simulations par forts vents, qui favorisent la circulation et les échanges de masses d’eau, présentent une diminution rapide des activités dissoutes. Par ailleurs, le Vent d’Est hivernal, qui engendre d’importantes crues du Las et un apport de sédiments à la Rade, favorise le piégeage des radionucléides dans les sédiments de fond, où les deuxtiers de la contamination initiale sont piégés après une simulation de deux mois

Hydro-sedimentary model as a post-accidental management tool: Application to radionuclide marine dispersion in the Bay of Toulon (France)

International audienc

Spatial risk assessment in case of multiple nuclear release scenarios

International audienc

Origin of flash flood water of a Mediterranean river in karstic and urban environments by CTD monitoring (Las - Toulon - SE France)

International audienceThis study deals with flash flood generation in Mediterranean karstic and urban environments. Flash floods in streams are characterized by short response times to rainfall events, and high and rapid discharge variations (Nied et al. 2014, Merz and Böschl 2003, Gaume et al. 2009). They are usually generated by short, high-intensity rainfalls, mainly of convective origin that occur locally. In urban environments, impermeable areas and storm water conveyance systems significantly increase the flash floods caused by storm runoff (Miller et al. 2014). Moreover, in karstic environments, the karst groundwater baseflow supplying the stream can be highly variable. The karst groundwater discharge, mainly flowing at springs, is also disturbed by rainfall events that could quickly recharge the aquifer through permeable karst features (sinkholes, caves, shafts, karrens, open fractures…) in the catchment area and propagate through vadose and saturated zones. The resulting flood from the karst groundwater overflows into the stream. Simultaneous discharge of urban runoff origin and groundwater origin increase flash flood and hazard consequences