The 210Pb-based method has been widely used for five decades to determine absolute ages in recent sediments on the centennial scale. Decoding a chronology from the empirical data set requires a series of assumptions that define a mathematical model of the sedimentary conditions. This work aims to provide a comprehensive review of the fundamentals of the existing family of models assuming a constant flux of excess 210Pb at the sediment surface, namely the CFCS, CRS, and PLUM models, and to present the novel χ-mapping versions of the CFCS and CF models. Their performance is assessed with a selected group of five cores from literature data, with varve chronologies or independent time marks. The PLUM model did not produce reliable chronologies in any of the cores studied. The CRS model is too sensitive to an accurate estimation of the total inventory. A weighted-fit and the χ-mapping versions of the CFCS model are prone to over-represent the younger regions of the core. The CFCS model with least squares fitting and the χ-CF models performed best under the most common sedimentary conditions, which involve temporal variability in the fluxes randomly distributed in the time line. A practical strategy is suggested to identify the occurrence of such sedimentary conditions through the combined use of a set of models, providing this way further strength to the 210Pb-dating.

Estimation of effective dose and dose to the lens of the eye for workers involved in interventional procedures is challenging. The interventional procedures in question involve high doses and, due to this, workers need to wear protective garments. As a result, various methodologies have been developed to assess the effective dose and dose to the lens of the eye. In the present study, measurements from four European dosimetry services, over and under protective garments, have been collected and analysed in order to provide practical guidelines based on the routine use of personal dosemeters from staff in interventional workplaces. The advantages and limitations of using one or two dosemeters are discussed.

This paper presents a series of electromagnetic field measurements performed on the campus of Ferdowsi University of Mashhad in order to assess the compliance of radiation levels of cellular base stations and WiFi access points with international guidelines. A calibrated, broadband and isotropic probe is used and recommendations of International Telecommunication Union (ITU) are followed up throughout measurements. More than 300 outdoor and indoor locations have been systematically chosen for measurements. The recorded data are post-processed and compared with the guideline of International Commission on Non-Ionizing Radiation Protection (ICNIRP). Measured power densities of WiFi access points are low and do not exceed 1% of the level allowed by ICNIRP. For cellular base stations, measured power density is usually low outdoors, but reaches up to 16% of the allowed radiation level in publicly accessible indoor locations. Comprehensive exposure assessment, as recommended by ITU, has been performed to estimate the maximum possible radiation of one indoor base station. It is concluded that precautionary actions have to be taken by university authorities to limit the presence of students in close proximity to specific indoor antennas. Moreover, comprehensive exposure assessment is more likely necessary for indoor base stations whereas such assessment is not usually required outdoors.

Cost-risk-benefit analysis has been applied to protection of the patient in diagnostic radiology with special reference to the application of referral guidelines. The analysis presented has extended previous work in this field to provide a theoretical framework that encompasses key factors that need to be considered in the optimisation of patient protection from both diagnostic and radiation risks. The fraction of patients whose symptoms do not meet criteria contained in the referral guidelines and, therefore, for whom an X-ray examination is not indicated has been termed the selectivity of the guidelines. Also included are the detriments arising from rejected or repeated examinations as well as the levels of patient dose employed in order to achieve given levels of true and false diagnostic outcomes. A comprehensive framework for optimisation is outlined and its relationship to justification discussed.

More than 10,000 whole organism concentration ratio (CRwo-water) values for freshwater wildlife were derived from radionuclide and stable element data representing an Australian tropical U mining environment. The CRwo-water values were summarised into five wildlife groups (bird, fish, mollusc, reptile and vascular plant). The summarised CRwo-water values represented 77 organism-element combinations. The CRwo-water values for U decay series elements were used in a tier 3 ERICA assessment. The assessment results were used to derive a water radiological quality guideline value (GV) for radiation protection of freshwater ecosystems in the context of the planned remediation of the Ranger U mine. The GV was an above-background water 226Ra activity concentration of 14 mBq L-1 (filtered fraction) or approximately 22 mBq L-1 (total fraction). The GV was based on the results of mollusc-bivalve as the limiting organism for the freshwater ecosystem.

Existing and future nuclear fusion technologies involve the production and use of large quantities of tritium, a highly volatile, but low toxicity beta-emitting isotope of hydrogen. Tritium has received international attention because of public and scientific concerns over its release to the environment and the potential health impact of its internalization. This article provides a brief summary of the current state of knowledge of both the biological and regulatory aspects of tritium exposure; it also explores the gaps in this knowledge and provides recommendations on the best ways forward for improving our understanding of the health effects of low-level exposure to it. Linking health effects specifically to tritium exposure is challenging in epidemiological studies due to high uncertainty in tritium dosimetry and often suboptimal cohort sizes. We therefore argued that limits for tritium in drinking water should be based on evidence derived from controlled in vivo animal tritium toxicity studies that use realistically low levels of tritium. This article presents one such mouse study, undertaken within an international collaboration, and discusses the implications of its main findings, such as the similarity of the biokinetics of tritiated water (HTO) and organically bound tritium (OBT) and the higher biological effectiveness of OBT. This discussion is consistent with the position expressed in this article that in vivo animal tritium toxicity studies carried out within large, multi-partner collaborations allow evaluation of a great variety of health-related endpoints and essential to the development of international consensus on the regulation of tritium levels in the environment. Environ. Mol. Mutagen. 59:586-594, 2018. © 2018 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society.

暂无摘要。

暂无摘要。

The IDEAS Guidelines [Doerfel, H., et al General Guidelines for the Estimation of Committed Effective Dose from Incorporation Monitoring Data. Report FZKA 7243, Forschungszentrum Karlsruhe, GmbH (2006); Castellani, C. M., Marsh, J. W., Hurtgen, C., Blanchardon, E., Berard, P., Giusani, A. and Lopez, M. A. IDEAS Guidelines (Version 2) for the Estimation of Committed Doses from Incorporation Monitoring Data. EURADOS Report 2013-01, Braunschweig (2013)] provide a structured approach to the assessment of intakes of radionuclides. In order to check that the guidelines, when applied to typical monitoring programmes, lead to reliable assessments, a number of numerically-generated datasets have been constructed and assessed using the guidelines. The dose and intake obtained by the assessment can be compared with the \'true\' dose and intake. In this way, the accuracy of the IDEAS assessment process can be examined when applied to monitoring programmes that are typically used in the nuclear industry. The simulations focus on assessments carried out as a result of elevated (239)Pu activities in routine urine samples, which lead to follow-up urine and faecal samples being provided. Cases where the assessor makes the correct initial assumption about lung solubility can be compared with cases where this initial choice is wrong. The results of these simulations and the implication for the use of monitoring programmes are discussed.

Dose assessment after intakes of radionuclides requires application of biokinetic and dosimetric models and assumptions about factors influencing the final result. In 2006, a document giving guidance for such assessment was published, commonly referred to as the IDEAS Guidelines. Following its publication, a working group within the European networks CONRAD and EURADOS was established to improve and update the IDEAS Guidelines. This work resulted in Version 2 of the IDEAS Guidelines, which was published in 2013 in the form of a EURADOS report. The general structure of the original document was maintained; however, new procedures were included, e.g. the direct dose assessment method for (3)H or special procedure for wound cases applying the NCRP wound model. In addition, information was updated and expanded, e.g. data on dietary excretion of U, Th, Ra and Po for urine and faeces or typical and achievable values for detection limits for different bioassay measurement techniques.