Combining short-range dispersion simulations with fine-scale meteorological ensembles: probabilistic indicators and evaluation during a ⁸⁵Kr field campaign

Numerical atmospheric dispersion models (ADMs) are used for predicting the health and environmental consequences of nuclear accidents in order to anticipate countermeasures necessary to protect the populations. However, these simulations suffer from significant uncertainties, arising in particular from input data: weather conditions and source term. Meteorological ensembles are already used operationally to characterize uncertainties in weather predictions. Combined with dispersion models, these ensembles produce different scenarios of radionuclide dispersion, called “members”, representative of the variety of possible forecasts. In this study, the fine-scale operational weather ensemble AROME-EPS (Applications of Research to Operations at Mesoscale-Ensemble Prediction System) from Météo-France is coupled with the Gaussian puff model pX developed by the IRSN (French Institute for Radiation Protection and Nuclear Safety). The source term data are provided at 10 min resolution by the Orano La Hague reprocessing plant (RP) that regularly discharges 85Kr during the spent nuclear fuel reprocessing process. In addition, a continuous measurement campaign of 85Kr air concentration was recently conducted by the Laboratory of Radioecology in Cherbourg (LRC) of the IRSN, within 20 km of the RP in the North-Cotentin peninsula, and is used for model evaluation. This paper presents a probabilistic approach to study the meteorological uncertainties in dispersion simulations at local and medium distances (2–20 km). First, the quality of AROME-EPS forecasts is confirmed by comparison with observations from both Météo-France and the IRSN. Then, the probabilistic performance of the atmospheric dispersion simulations was evaluated by comparison to the 85Kr measurements carried out during a period of 2 months, using two probabilistic scores: relative operating characteristic (ROC) curves and Peirce skill score (PSS). The sensitivity of dispersion results to the method used for the calculation of atmospheric stability and associated Gaussian dispersion standard deviations is also discussed. A desirable feature for a model used in emergency response is the ability to correctly predict exceedance of a given value (for instance, a dose guide level). When using an ensemble of simulations, the “decision threshold” is the number of members predicting an event above which this event should be considered probable. In the case of the 16-member dispersion ensemble used here, the optimal decision threshold was found to be 3 members, above which the ensemble better predicts the observed peaks than the deterministic simulation. These results highlight the added value of ensemble forecasts compared to a single deterministic one and their potential interest in the decision process during crisis situations.</p

Natural radionuclide of Po210 in the edible seafood affected by coal-fired power plant industry in Kapar coastal area of Malaysia

<p>Abstract</p> <p>Background</p> <p>Po²¹⁰can be accumulated in various environmental materials, including marine organisms, and contributes to the dose of natural radiation in seafood. The concentration of this radionuclide in the marine environment can be influenced by the operation of a coal burning power plant but existing studies regarding this issue are not well documented. Therefore, the aim of this study was to estimate the Po²¹⁰concentration level in marine organisms from the coastal area of Kapar, Malaysia which is very near to a coal burning power plant station and to assess its impact on seafood consumers.</p> <p>Methods</p> <p>Concentration of Po²¹⁰was determined in the edible muscle of seafood and water from the coastal area of Kapar, Malaysia using radiochemical separation and the Alpha Spectrometry technique.</p> <p>Results</p> <p>The activities of Po²¹⁰in the dissolved phase of water samples ranged between 0.51 ± 0.21 and 0.71 ± 0.24 mBql^-1whereas the particulate phase registered a range of 50.34 ± 11.40 to 72.07 ± 21.20 Bqkg^-1. The ranges of Po²¹⁰activities in the organism samples were 4.4 ± 0.12 to 6.4 ± 0.95 Bqkg^-1dry wt in fish (<it>Arius maculatus</it>), 45.7 ± 0.86 to 54.4 ± 1.58 Bqkg^-1dry wt in shrimp (<it>Penaeus merguiensis</it>) and 104.3 ± 3.44 to 293.8 ± 10.04 Bqkg^-1dry wt in cockle (<it>Anadara granosa</it>). The variation of Po²¹⁰in organisms is dependent on the mode of their life style, ambient water concentration and seasonal changes. The concentration factors calculated for fish and molluscs were higher than the recommended values by the IAEA. An assessment of daily intake and received dose due to the consumption of seafood was also carried out and found to be 2083.85 mBqday^-1person^-1and 249.30 μSvyr^-1respectively. These values are comparatively higher than reported values in other countries. Moreover, the transformation of Po²¹⁰in the human body was calculated and revealed that a considerable amount of Po²¹⁰can be absorbed in the internal organs. The calculated values of life time mortality and morbidity cancer risks were 24.8 × 10^-4and 34 × 10^-4respectively which also exceeded the recommended limits set by the ICRP.</p> <p>Conclusions</p> <p>The findings of this present study can be used to evaluate the safety dose uptake level of seafood as well as to monitor environmental health. However, as the calculated dose and cancer risks were found to cross the limit of safety, finding a realistic way to moderate the risk is imperative.</p

Anaerobic digestion and gasification of seaweed

The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, with over 70 years of sometimes intensive research and considerable financial investment. A wide range of unit operations can be combined to produce algal biofuel, but as yet there is no successful commercial system producing such biofuel. This suggests that there are major technical and engineering difficulties to be resolved before economically viable algal biofuel production can be achieved. Both gasification and anaerobic digestion have been suggested as promising methods for exploiting bioenergy from biomass, and two major projects have been funded in the UK on the gasification and anaerobic digestion of seaweed, MacroBioCrude and SeaGas. This chapter discusses the use of gasification and anaerobic digestion of seaweed for the production of biofuel

Variations of 210Po and 210Pb in various marine organisms from Western English Channel: contribution of 210Po to the radiation dose

Measurements of 210Po were carried out in various marine matrices (mussels, oysters, seaweed, fish, and abalones) and in seawater at several points along the French coast, over a period of 2 years (2003-2005). These measurements contribute to a better knowledge of this element, since few recent data exist for the French coast. Marked seasonal variations have been revealed in some species and there are differences according to the way of life of these species. Activities in mussels (Mytilus edulis) and oysters (Crassostrea gigas) are similar and varying between 90 and 600 Bq kg-1 (d.w.). Activities in macroalgae (Fucus serratus) are lowest, between 4 and 16 Bq kg-1 (d.w.). In oyster, abalone (Haliotis tuberculata) and fish (Solea solea, Sparus sp.), the strongest activities are measured in the digestive glands, the gills and the gonads. 210Po/210Pb ratios in all cases have values of more than one for all species. From a significant number of measurements, CFs were calculated for seaweed (between 4.6 × 103 and 5.0 × 103) and for molluscs, with highest CFs (&gt;105) found for the digestive gland and gills of the oysters, the digestive gland of the abalones and the liver of fish. Finally, the activities measured have made it possible to estimate the internal dose from chronic exposure due to 210Po received by the marine organisms (0.05 μG h-1 for macroalgae, between 0.70 and 1.5 μG h-1 for mussels and oyster), and the contribution of seafood to the dose received by humans (46-129 μSv y-1). © 2007 Elsevier Ltd. All rights reserved

The bituminous mixtures of Kavuşan Höyük (SE Turkey) from the end of the 3rd millennium (2000BC) to the Medieval period (AD 14th century): Composition and origin

Bituminous mixtures were observed on potsherds at Kavuşan Höyük, one of the rescue excavations along the Upper Tigris River in southeastern Turkey. Analysis of 26 samples from six periods spanning from the end of the 3rd millennium BC to the Medieval period (AD 14th century), has shown that bituminous mixtures possess the classical gross composition of most bitumen-bearing mixtures analysed in many archaeological sites of the Near East and the Gulf of Arabia. To search for the geological sources of bitumen, oil seeps, oil stained rocks and crude oils from Turkey and Northern Iraq were analysed as reference using the same geochemical tools: biomarkers and stable isotope composition. The principal conclusion is that the bitumen has been imported from the Eruh outcrop, 120. km east of Kavuşan Höyük. Additionally, the bitumen from Eruh was imported to Kavuşan over a long time period, from the end of the 3rd millennium BC to the AD 14th century. © 2012 Elsevier Ltd

The bituminous mixtures of Kavusan Hoyuk (SE Turkey) from the end of the 3rd millennium (2000 BC) to the Medieval period (AD 14th century): Composition and origin

WOS: 000314458000002Bituminous mixtures were observed on potsherds at Kavusan Hoyuk, one of the rescue excavations along the Upper Tigris River in southeastern Turkey. Analysis of 26 samples from six periods spanning from the end of the 3rd millennium BC to the Medieval period (AD 14th century), has shown that bituminous mixtures possess the classical gross composition of most bitumen-bearing mixtures analysed in many archaeological sites of the Near East and the Gulf of Arabia. To search for the geological sources of bitumen, oil seeps, oil stained rocks and crude oils from Turkey and Northern Iraq were analysed as reference using the same geochemical tools: biomarkers and stable isotope composition. The principal conclusion is that the bitumen has been imported from the Eruh outcrop, 120 km east of Kavusan Hoyuk. Additionally, the bitumen from Eruh was imported to Kavusan over a long time period, from the end of the 3rd millennium BC to the AD 14th century. (C) 2012 Elsevier Ltd. All rights reserved

ORGANIC GEOCHEMICAL CHARACTERISTICS OF SIRNAK ASPHALTITES IN SOUTHEAST ANATOLIA, TURKEY

In this study, the organic geochemical properties of asphaltites in,Sirnak region in Southeast Anatolia are given in detail. Total organic carbon, Rock-Eval pyrolysis, gas chromatography of saturated fractions, gas chromatography-mass spectrometry and stable carbon isotope (delta(13)C in parts per thousand/PDB) analysis were conducted on the,5irnak region asphaltite seams. Some of these analyses were performed for the host rocks as well. It is suggested that a live oil seep occurs within asphaltites, which themselves may be formed in a multiple phase system

Contribution to reducing uncertainties regarding the dry deposition velocities of fine aerosols: Study case of a prairie (description of experimental methods and comparison with models)

In the context of environmental protection, the transfer of aerosols to vegetative canopies must be properly estimated, since aerosols constitute a preferential transport pathway for atmospheric pollution (bacteriological, chemical or radioactive). In order to properly assess the transport of pollutants, it is essential to accurately determine their dry deposition fluxes. Previous studies conducted around a nuclear site showed that the deposition prediction models do not yield an accurate representation of measured radionuclide activity (mainly 106Ru) in grasses, with observed discrepancies probably attributable to an underestimate of the dry deposition velocities. In addition, the literature mentions uncertainties in the order of two decades for the deposition velocities of particles larger than 1 urn, and little experimental data is available for submicronic particles. In order to reduce these uncertainties and choose a suitable model, a series of experiments to measure the dry deposition velocities of aerosols has been scheduled for 2005-2007. This document presents the method used and the results obtained for a fine aerosol (0.24 μm) dispersed over a prairie under neutral or unstable meteorological conditions. The technique used consists of generating a monodispersed fluorescein aerosol. The fluorescein concentration is measured in the grass and air by spectrofluorimetry and used to obtain the dry deposition velocities. A second approach using natural radioactivity (214Pb) and gamma spectrophotometry measurements has enabled the confirmation of the results obtained. The mean deposition velocities measured in this first series of experiments for a prairie-type substrate vary between 4 10-4 and 2 10-3 m.s-1. The comparison with the Slinn, Zhang and Wesely models shows that the first of these underestimates the deposition velocities by a factor of 5 to 20 and the other two more accurately represent the experimental measurements, with model/measurement discrepancies of generally less than 2