Browsing by Author "Charmasson, S"

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    Exploring new frontiers in marine radioisotope tracing – adapting to new opportunities and challenges
    (Frontiers Media S.A., 2020-06-03) Cresswell, T; Metian, M; Fisher, NS; Charmasson, S; Hansman, RL; Bam, W; Bock, C; Swarzenski, PW
    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. © 2020 Cresswell, Metian, Fisher, Charmasson, Hansman, Bam, Bock and Swarzenski. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).
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    Global seafood dose 2023: assessment by an international team
    (ICRP, 2023-11-06) Johansen, MP; Carpenter, JG; Charmasson, S; Gwynn, JP; McGinnity, P; Mori, A; Orr, B; Simon-Cornu, M; Osvath, I
    It has been known for many years that ingestion dose from seafood is an important component of the background dose rates for billions of consumers worldwide and that eating seafood can contribute proportionally higher dose as compared with terrestrial-sourced foods. However, a well-supported and current estimate of the contribution of seafood to the dose of global consumers is not available. This is mainly because of the difficulty in assembling the underlying data on a global scale, but also due to the varied and dynamic nature of exposures. Global seafood consumption is increasing, diet patterns are shifting (e.g., toward more farmed products), and new inputs of radionuclides into marine systems have occurred (e.g., the Fukushima accident). A new assessment is being conducted on seafood dose in the context of the ongoing stresses on ocean resources and protection of the marine environment. Its global scale makes use of a much-expanded database on radionuclides in seafood (Marine Radioactivity Information System -MARIS) as well as global diet data and updated parameters for dose calculation. The new assessment: • Evaluates global data on 16 natural and anthropogenic radionuclides. • Draws from more than 84,856 activity concentrations data for biota. • Uses seafood consumption data representing approximately 35% of the world population drawn from national and sub-national diet studies. • Develops new correction factors for the loss of 210Po during cooking, radiological decay during storage, as well as the decreases in 210Po in maricultured seafood. • Implements a bespoke Monte Carlo application for calculating seafood dose distributions. • Compiles and evaluates 150+ seafood ingestion dose estimates published in the past 30 years. The new results indicate somewhat higher seafood dose rates for typical global consumers than previous comprehensive assessments (UNSCEAR, MARDOS). Compared with the 150+ previous individual published studies, our distribution of global dose matches closely and helps explain and interpret the previous estimates. Most background seafood dose is from naturally-sourced 210Po (~80%) followed by 210Pb (+10%) and the Ra radionuclides (~7%). A comparatively small background dose (<0.01%) comes from the ambient anthropogenic radionuclides in seafood that derive from worldwide fallout, accidents, releases from waste sites and similar sources. Study outcomes are useful in providing benchmark references for dose assessments performed on the local, regional and national scale for planned facilities or for evaluating accidental releases. They also provide a baseline for quantifying the changes in seafood dose over time. Results show that typical seafood doses are changing as they reflect trends toward more maricultured products (which can have markedly lower levels of 210Po), various stresses and impacts on world fisheries as well as the evolution of seafood production and distribution systems. Numerous researchers and organisations worldwide have provided input into the project. The assessment is being conducted within the IAEA Coordinated Research Project “Behaviour and Effects of Natural and Anthropogenic Radionuclides in the Marine Environment and their Use as Tracers for Oceanography Studies.”