Data sets containing values below the limit of detection (LOD) are known as ‘censored data sets’. Such data sets are encountered regularly in most fields of environmental contaminant research. The current norm within environmental radioactivity research is to use substitution methods when analysing data sets that include values below the LOD, commonly replacing each LOD value with a value equal to half the LOD (LOD/2). However, this approach has no statistical basis and has implications when summarising or comparing data sets because it can lead to underestimates or overestimates of both the mean and the standard deviation. To remove the need to apply substitution methods, over the last four decades other fields of environmental science have been adopting statistical techniques developed for medical research applications. Despite the long history of applying these techniques in other fields and two recent environmental radioactivity publications that have used survival analysis techniques, there still seems to be reluctance within the environmental radioactivity research community to adopt these ‘new’ methods. This paper introduces the statistical techniques that can be used in place of LOD substitution, presents some guidance on the applicability of these techniques for different levels of data censoring and provides some examples of the use of these methods in various contexts. It is hoped the present paper will contribute to the evidence-base supporting the use of survival analysis within the field of environmental radioactivity research and go some way to changing the current norm of substitution using LOD/2.

Coal, bottom ash and fly ash samples were collected from three different coal-fired thermal power plants in India and subjected to gamma spectrometry analysis for natural radioactivity contents. The results of present study show that fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. None of the fly-ash and bottom ash samples had radium equivalent activities and external hazard index values more than 370 Bq kg–1 and unity respectively. However the absorbed dose rate at 1 m above the ash pond was 79.19n Gy h–1 (average of 3 plants) higher than the global average value of 55 nGy h–1. The corresponding annual external effective dose is estimated to be 0.68 mSv y–1, which is also more than that (0.46 mSv y–1) in areas of natural background radiation. The 5th percentile, 95th percentile and mean values for total inhalation risk arising from radionuclides (Ra226, Th228, Pb210 and Nat-U) were found to be 3.83 × 10−9, 6.50 × 10−8 and 2.08 × 10−8 respectively.

The mass attenuation coefficient (µ/ρ), effective atomic number (ZPleff)and effective electron density (Neff) of carbon steel and stainless steels werecomputed by using the WinXcom program. The µ/ρ values are higher in the photo-electricabsorption and pair production region and approximately constant in the Compton scatteringregion. The variation in µ/ρ values is explained by partial interaction processes. Theeffective atomic numbers of the steels were also calculated by the Auto-Zeffprogram. The ZPleff values of the steels were compared with experimental resultsfor available energies and were found to be in good agreement. SS304L shows equal values ofeffective atomic number by both the methods in the region of interest. The electrondensities of the selected steels are observed to be equal and approximately constant in theCompton scattering region.

Un nouveau dispositif de dosimétrie par photoluminescence (PLD), entièrement automatique, constitué d'un verre photoluminescent à un élément et du système de lecture Toshiba FGD-10, est désormais commercialisé. Il a été testéau Physikalisch-Technische Bundesanstalt (PTB) et introduit en surveillance de routine. En raison, avant tout, des propriétés dosimétriques spécifiques de sonverre, le dispositif PLD s'est avéré supérieur aux dosimètres photographiques ou thermoluminescents. Sont discutés, ici, du point de vue de l'application en routine, le dispositif de dosimetrie utilisant l'excitation par laser-UV pulsé et sespropriétés dosimétriques - énergie et réponse angulaire, incertitude aléatoire et paramètres d'ambiance affectant la mesure de la dose. Les principaux avantagessont la faible pré-dose (30 ± 1 µSv) des verres recuits, le faible coefficient de variation (2% à 1 mSv) qui permet la mesure de doses supérieures à 10 µSv, lastabilité à long terme des doses mesurées (environ 1%), la réponse en fonction de l'énergie et la réponse angulaire pour l'indication simultanée de différentes grandeurs dosimétriques (par ex. X en espace libre ou Hp(10) sur fantôme plaque dans le domaine d'énergie de 12 keV à 1,3 MeV. Comparés à d'autresdispositifs, les résultats des tests d'homologation et la participation à une intercomparaisonde dosimètres individuels, sous l'égide de l'Agence internationale de l'énergie atomique (AIEA) d'une part et d'autre part l'utilisation en routineconfirment les progrès de la dosimétrie par photoluminescence et la précision dela mesure même par température ambiante élevée dans le cadre de la surveillance individuelle ou de l'environnement.

Uranium behaviour in soils is controlled by actions and interactions between physico-chemical and biological processes that also determine its bioavailability. In soil solution, uranium (+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach, plants (Phaseolus vulgaris) were grown using hydroponics to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. A geochemical speciation code was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, the influence of plant growth stage on transfer was determined. The Free Ion Model (or its derivated the Biotic Ligand Model) was tested to determine if U uptake was governed by the free uranyl species or if other metal complexes could be assimilated. The effect of different variables on root assimilation efficiency and phytotoxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca2+ at the 3 pHs. 


The mass concentration of uranium in water samples collected from the Bathinda districtof Punjab state, India, was estimated using the laser fluorimetric technique. The studyregion has shown a pronounced number of cancer cases in the recent period. The study aimsto calculate the human radiological risk and chemical toxicity associated with uraniumconsumption through drinking water. The mass concentration of uranium was found to varyfrom 0.48 to 571.7 μg/l with a mean value of 84.70 μg/l. The radiological risk due toconsumption of uranium through contaminated drinking water was observed to be in the rangeof 1.34 × 10-6 to 1.60 × 10-3 with a mean value of2.37 × 10-4. The chemical toxicity was found to vary from 0.04–43.11µg.kg-1.day-1 with a mean value of 6.38µg.kg-1.day-1.

We calculated mass attenuation coefficients, effective atomic numbers and Kerma relative to air for human organ and tissue substitutes (i.e.wax, plastic and polymer materials). The effective atomic numbers of the tissue substitutes were calculated by the direct method, interpolation method, Auto-Zeff software and single value XMuDat program and then compared. The calculated effective atomic numbers were also compared with available experimental data and a good agreement was observed. A large difference in effective atomic numbers calculated by the direct and interpolation methods was observed in photoelectric and pair-production regions. The direct method was found to be appropriate for effective atomic number computation in low-(>10 keV) and medium-(0.1 ≤ E ≤ 10 MeV) photon energy regions. Kerma relative to air of the selected tissue substitutes was found to be dependent upon the atomic number and element compositions, which show a sharp peak due to K-edge absorption.

Zebrafish were exposed to different concentrations of waterborne uranium (0, 20, 100 and 500 μg U.L-1) and were sacrificed for blood sampling after different exposure periods (12h, 36h, 72h, 5, 10 and 20 days) in order to assess DNA integrity in erythrocytes, using the comet assay and flow cytometry. Concurrently, uranium bioaccumulation was studied in the remaining tissues to understand the potential genotoxic biomarker responses. Both genotoxic assays revealed significant effect of waterborne uranium on DNA integrity of fish erythrocytes. However, comet assay only succeeded in detecting such an effect after a 20-day exposure whereas flow cytometry analysis showed a uranium concentration effect for any exposure duration. Regarding uranium bioaccumulation, significant effects of both uranium concentration and exposure duration have been highlighted in this experiment.

Within the last ten years there has been increasinginterest in tritium behaviour and distribution in the environment.This is based partly on empirical findings that tritium dischargedmostly as HTO can become transformed into organic forms in environmentalsamples. An international workshop was convened in France in 2012 togather the scientific community interested in organically boundtritium to share their experience and to establish a current stateof knowledge. This paper summarises the outcome of the workshop,which aimed to improve skills concerning OBT (OrganicallyBound Tritium) determination, transfer and behaviour in the environment.In order to improve OBT measurement credibility,it was decided to conduct and promote OBT analysisthrough inter-laboratory exercises. This practice will reduce uncertaintyin OBT analysis results, providing better OBT modelvalidation data and public dose assessments.

Precise and accurate estimation of natural radioactivity is essential in order toappraise the radiation dose to the member of public due to various intakes. In the presentstudy, an attempt has been made to estimate the uranium content in packaged drinking waterby laser induced fluorimetry and then to calculate the committed effective dose. Sixtypackaged drinking water samples of different brands were analysed for uranium content. Thetotal uranium content in these samples was found to be in the range of 0.04–3.88µg l-1. The concentration of uranium is comparable with other reportedworldwide values except a few high values such as 0.5–6000 µg l-1 in Finland,0.1–28 µg l-1 in China, 0.1–40 µg l-1 in Switzerland and 0.04–1400µg l-1 in Jordan and much lower than the drinking water limit of 15µg l-1 (WHO, 2004) and 30 µg l-1 (USEPA, 2000a). The radiationdose due to uranium ingestion through packaged drinking water was found to vary from0.08–3.19 µSv y-1, with an average dose of 1.21 µSv y-1.

Farming on soils situated in high background radiation areas can result to enhanced radiation exposure scenarios and pathways to humans. To assess the likely levels of exposures, farm soil samples were collected from different farmlands in three old tin mining localities (Bitsichi, Bukuru and Ropp) in Jos Plateau Nigeria, known for high radiations. The soil samples were analyzed for the activity concentrations of 226Ra, 232Th and 40K, using gamma-ray spectroscopy. The outdoor annual effective dose rates were calculated using the activity concentrations of the radionuclides and were found to vary from 0.07 mSv to 2.02 mSv across the three localities. Considering dust generation from soil tillage and inadvertent ingestion of soil particles, the likely internal radiation hazards were estimated using conservative dust and soil loading factors. The total average annual effective dose rates due to 226Ra and 232Th that could result from dust inhalation and ingestion of soil particles were 16.9 µSv, 8.1 µSv and 8.8 µSv, respectively for Bitsichi, Bukuru and Ropp. Though these values are about 5% the outdoor exposures to the farmers in those farms and greater than 1 µSv y-1, from the point of view of radiation protection and risk, they are significant. It suffices to say, therefore, that the results of this study will create the possibility of the importance to evaluate the health risk among the farming population and workplace environments which often is not covered by regulations concerning health protection.

The large-scale nuclear accident took place at the production association “Mayak” in the Southern Urals in 1957. About 74 PBq of radioactive substances were released into the atmosphere, which resulted in the contamination of a vast area – East-Ural radioactive trace (EURT). The results of our study have shown that the density of contamination of 90Sr and 137Cs in the frontal part of the EURT are 6700–15000 and 200–400 kBq/m2, respectively. The total deposition for 90Sr within the East-Ural Radioactive State Reserve was 428.2 (286.4–643.4) TBq, for 137Cs – 15.1 (10.2–22.4) TBq, for 239,240Pu – 1.175 (0.623–2.242) TBq.

There is general international acceptance of the need to demonstrate that the environment is protected from ionising radiation. In some countries requirements and guidelines for the protection of non-human biota are already in place. As a consequence a number of models and approaches have been proposed for the estimation of the exposure of non-human biota to ionising radiation. The IAEA EMRAS programme's Biota Working Group has conducted the most comprehensive intercomparison of the predictions of these approaches to date. In this paper, we present an overview of the activities of the Biota Working Group concentrating on its conclusions and recommendations.

In some regions of Germany radiocaesium contamination of wild boar (Sus scrofa) is either staying fairly constant or slightly increasing on average, concurrently exhibiting an extraordinary variability. The reasons for this peculiar contamination pattern were investigated from 2002 to 2004 in an area located in the Bavarian forest. The microscopic analyses of 70 stomachs gave detailed information on the food composition. Potential food items sampled in the investigation area were measured for their radiocaesium level. Deer truffles (Elaphomyces granulatus), a preferred delicacy of wild boar, turned out to play a key role. This fungus showed contamination levels exceeding those of edible mushrooms and other food components by an order of magnitude and more. Despite their low weight proportion of about 6% of the stomach content on average, more than three quarters of the radiocaesium uptake can be ascribed to deer truffles. Their irregular consumption and the dynamics of radiocaesium in forest soil explain the peculiar contamination pattern of wild boar. Predictive modelling of radiocaesium contamination of wild boar should always take into account deer truffles, especially their occurrence, contamination levels and irregular consumption.

Zircon is the mostly widely occurring zirconium-containing mineral mined commercially. Thorium and uranium may substitute for zirconium in the zircon crystal lattice. The radioactivity levels in zircon lies typically within the ranges 500–1000 Bq kg-1 for 232Th and 1000–5000 Bq kg-1 for 238U [1]. One of the most important use of zircon is as opacifier for ceramic tiles. Body of ceramic tiles is a mixture of different raw materials, including: clays, quartz materials and feldspathic materials. The body may be glazed or left unglazed. Due to the presence of zircon in the glaze or in the body, ceramic tiles can show natural activity concentration significantly higher than the average values of Earth's crust. This study contains a summary of results obtained by a survey on Italian ceramic tiles collected over three years (2005–2007). About one hundred ceramic tiles were analysed. The survey consisted of measurement of 226Ra, 232Th and 40K activity concentrations and of the gamma-index [2] and radium-equivalent [3, 4] calculation. The activity concentrations of 226Ra, 232Th and 40K result in the order of 100, 50 and 500 Bq kg-1, respectively. Gamma index and radium equivalent activity have been found well below the acceptable limit in most of the samples.

The objectives of the present work were (1) to estimate the bioaccumulation of natural uranium (U) in a representative freshwater fish and (2) to assess the response of parameters involved in the defense against reactive oxygen species, in relation with the metal concentration and the exposure duration. Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to a range of U concentrations in water (20, 100 and 500 μg U l-1) during 10 days. The activity of antioxidant enzymes superoxide dismutases (SOD) and catalase were measured in trout liver. In parallel, U analysis were performed in water and in trout gills. A significant accumulation of U occurred in trout gills in relation with the concentrations of U in water. SOD and catalase activities were both decreased by the exposure to U. U seemed to partly inhibit the antioxidant system of trout, indicating a potential enlarged sensitivity of exposed fish to oxidative damages. 


Adaptive responses were observed using the micronucleus frequency in bullfrog tadpoles. In tanks in which control tadpoles were placed in contact with tadpoles that were previously housed in tritiated water (3.0 × 104 Bq/L), the cells from all animals responded as though they were “adapted”. This suggests that direct exposure to 3.0 × 104 Bq/L tritium contributes to an increased resistance to a high dose of radiation in liver cells. It also suggests that being in contact with tadpoles that were previously exposed to 3.0 × 104 Bq/L tritium (bystander effect) contributes to an increased resistance to a high dose of radiation in liver cells.

In vitro exposures were also conducted using primary cultures of liver cells obtained from an unexposed-non-bystander tadpole. In these control cells, it was observed that exposure to 100 mGy of 60Co gamma radiation (delivered at a dose rate of 5 mGy/min) did not affect the micronucleus frequency whereas exposure to 4 Gy (delivered at a dose rate of about 10.2 Gy/min) increased the micronucleus frequency. Prior exposure to a low dose of 60Co gamma radiation (100 mGy delivered at a dose rate of 5 mGy/min) induced an adaptive response, protecting the cells from harm caused by exposure to subsequent high doses of 60Co gamma radiation (4 Gy delivered at a dose rate of about 10.2 Gy/min). Using the adaptive response (determined using micronucleus assay) as a biomarker, the data obtained suggest that bystander effects do play a role in wild populations since bullfrog tadpoles that were not exposed to tritium responded like the tadpoles that were directly exposed to tritium after being placed in contact with them.

One of the major objectives of the 6th Framework EC RTD EURANOS (European Approach to Nuclear and Radiological Emergency Management and Rehabilitation Strategies) project was to improve the RODOS (Real-time on-line decision support) system in its operational applicability. In the first phase of the project two possibilities for the main system development has been discussed: either to carry out refinements in the current version of RODOS or to consider a complete software re-engineering. The RODOS Users Group (RUG) finally concluded that the latter option was one to be realised. As a result a JAVA based version named JRODOS has been developed introducing a cross-platform solution capable to run on most operation systems, including Windows, Macintosh and the main UNIX derivates. The re-engineered system preserves computational models from RODOS, adding a powerful GIS support and applying modern database technologies with flexible configuration possibilities. Furthermore, these new GIS functionalities allowed implementing advanced simulation models for simulating countermeasures in inhabited areas (ERMIN - European Model for Inhabited Areas) and food production systems (AGRICP – Agricultural Countermeasure Program). Both simulation models have been part of the EURANOS project and represent state of the art modelling capabilities in their respective area.

The Meteorological Pre-Processor (MPP) of the Decision Support System RODOS acts asinterface between the incoming meteorological data from stations and/or prognostic modelsand the Atmospheric Dispersion Models (ADMs) used for predicting the spread of theaccidentally emitted radionuclides. The MPP includes a diagnostic Wind Field Model (WFM)to ensure mass conservation of the calculated wind field. Its output is usable by simpleand complex ADMs and it is applicable for highly complex topography and from micro- tomeso-scales. The MPP has been tested for both real and artificial flow fields and it hasbeen optimized to function with very short execution times and to give the most reasonableresults under all terrain complexity and atmospheric stability conditions. DIPCOT(DIsPersion over COmplex Terrain) is a Lagrangian Puff / Particle model that has beenimplemented in RODOS to simulate radionuclides atmospheric dispersion over complicatedterrain. For this purpose, it uses a certain number of fictitious puffs/particles whichare assumed to move with the mean wind flow plus a random velocity component to simulateturbulent diffusion. The calculation of the gamma radiation dose rates in air due to theradioactive plume is calculated by a very fast method that takes into account theinhomogeneous 3-dimensional cloud shape. DIPCOT has been evaluated by comparisons towidely used real-scale experimental data sets: Copenhagen, Prairie Grass, Indianapolis andMol. The integration of the above models greatly enhances the applicability of the RODOSsystem.