Exploring new frontiers in marine radioisotope tracing - adapting to new opportunities and challenges

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Cresswell, T., Metian, M., Fisher, N. S., Charmasson, S., Hansman, R. L., Bam, W., Bock, C., & Swarzenski, P. W. Exploring new frontiers in marine radioisotope tracing - adapting to new opportunities and challenges. Frontiers in Marine Science, 7, (2020): 406, doi:10.3389/fmars.2020.00406.Radioisotopes have been used in earth and environmental sciences for over 150 years and provide unique tools to study environmental processes in great detail from a cellular level through to an oceanic basin scale. These nuclear techniques have been employed to understand coastal and marine ecosystems via laboratory and field studies in terms of how aquatic organisms respond to environmental stressors, including temperature, pH, nutrients, metals, organic anthropogenic contaminants, and biological toxins. Global marine issues, such as ocean warming, deoxygenation, plastic pollution, ocean acidification, increased duration, and intensity of toxic harmful algal blooms (HABs), and coastal contamination are all impacting marine environments, thereby imposing various environmental and economic risks. Being able to reliably assess the condition of coastal and marine ecosystems, and how they may respond to future disturbances, can provide vital information for society in the sustainable management of their marine environments. This paper summarizes the historical use of radiotracers in these systems, describes how existing techniques of radioecological tracing can be developed for specific current environmental issues and provides information on emerging issues that would benefit from current and new radiotracer methods. Current challenges with using radioecological tracers and opportunities are highlighted, as well as opportunities to maximize the application of these methods to greatly increase the ability of environmental managers to conduct evidence-based management of coastal and marine ecosystems.The IAEA is grateful for the support provided to its Environment Laboratories by the Government of the Principality of Monaco. This contribution was made within the framework of the IAEA CRP on “Applied radioecological tracers to assess coastal and marine ecosystem health” (K41019)

Fukushima Daiichi-derived radionuclides in the ocean: Transport, fate, and impacts

The events that followed the Tohoku earthquake and tsunami on March 11, 2011, included the loss of power and overheating at the Fukushima Daiichi nuclear power plants, which led to extensive releases of radioactive gases, volatiles, and liquids, particularly to the coastal ocean. The fate of these radionuclides depends in large part on their oceanic geochemistry, physical processes, and biological uptake. Whereas radioactivity on land can be resampled and its distribution mapped, releases to the marine environment are harder to characterize owing to variability in ocean currents and the general challenges of sampling at sea. Five years later, it is appropriate to review what happened in terms of the sources, transport, and fate of these radionuclides in the ocean. In addition to the oceanic behavior of these contaminants, this review considers the potential health effects and societal impacts

Distribution of organic carbon, selected stable elements and artificial radionuclides among dissolved, colloidal and particulate phases in the Rhoˆne River (France): Preliminary results

International audienceThe behaviour of radionuclides discharged from nuclear facilities in the Rhône River depends on their distribution among the dissolved, colloidal and particulate phases. A large water sample was fractionated using sequential ultrafiltration. Size distributions of organic carbon, Fe, Al, Si, Ca, Mg, Cu, Zn, 137Cs, 60Co and 106Ru were obtained. Our results show that organic colloids account for 11% of the total organic carbon content. Approximately 20% of the dissolved (<450 nm) Fe and Al are in colloidal classes. 137Cs is not significantly transferred by the colloidal phase while 25% of 60Co or 106Ru is associated with organic and inorganic colloids

Importance of colloids in the transport within the dissolved phase (<450 nm) of artificial radionuclides from the Rhône river towards the Gulf of Lions (Mediterranean Sea)

International audienceThe significance of colloidal fractions regarding the transport of artificial radionuclides innatural water systems is underlined by using sequential ultrafiltration both in the Rhoˆnefreshwater and the marine area under and outside the influence of the river outflow. Indeed,the Rhodanian aquatic system represents an interesting test site as various artificial radionuclides are released into the Rhoˆne river by several nuclear installations. We focused ourstudy on 137Cs, 106Ru, 60Co, 238Pu and 239+240Pu. Our results show that Fe, Al and Organiccarbon (OC) are the main components of colloidal matter. Colloids represent about 15% ofdissolved (<450 nm) OC and 25% of dissolved Fe and Al exported towards the sea. Withinthe dissolved (< 450 nm) phase, these colloidal compounds are shown to account for thetransport of 40% for both Co and Ru, 60% for 238Pu and 239+240Pu and have no significanceon 137Cs flu

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

Assessment of Sky Diffuse Irradiance and Building Reflected Irradiance in Cast Shadows

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Dynamique sédimentaire et vairabilité temporelle de la contrainte de cisaillement de fond face à l'embouchure du Rhône

International audienceno abstrac

Dynamique sédimentaire et vairabilité temporelle de la contrainte de cisaillement de fond face à l'embouchure du Rhône

International audienceno abstrac

Suspended Particulate Matter Monitoring with GOCI Images After the Tohoku Tsunami (March 2011)

International audienceThe Fukushima Daiichi nuclear disaster on 11 March 2011 was caused by the tsunami which was itself triggered by the devastating moment magnitude Mw9.0 earthquake. The present study investigates spatial and temporal changes of Suspended Particulate Matter (SPM) contents in the North-Eastern part of Japan, in the Pacific Ocean after the tsunami with a geostationary ocean color sensor. The Geostationary Ocean Color Imager (GOCI) launched in 2010, covers an area of 2,500 km x 2,500 km centered on the Korean peninsula, including the Japanese area and provides 8 images per day allowing the analysis of rapid changes that can occur during the day. Corrected from the atmospheric effect, the images were used to estimate the SPM concentrations maps. These maps were then analyzed between 5 March and 25 May 2011. The SPM notably increased (by 250%) both along the coast and in the Bay of Sendai shortly after the tsunami and stable structures of SPM appeared at 2, 14, 25 and 37 km from the coast. In this paper we attempt to explain the origin and the fate of the SPM concentration observed till the end of May 2011 through analysis of meteorological conditions, river discharges and tsunami waves properties