146 research outputs found

    Adverse outcome pathways (AOPs) for radiation-induced reproductive effects in environmental species: state of science and identification of a consensus AOP network

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    Background Reproductive effects of ionizing radiation in organisms have been observed under laboratory and field conditions. Such assessments often rely on associations between exposure and effects, and thus lacking a detailed mechanistic understanding of causality between effects occurring at different levels of biological organization. The Adverse Outcome Pathway (AOP), a conceptual knowledge framework to capture, organize, evaluate and visualize the scientific knowledge of relevant toxicological effects, has the potential to evaluate the causal relationships between molecular, cellular, individual, and population effects. This paper presents the first development of a set of consensus AOPs for reproductive effects of ionizing radiation in wildlife. This work was performed by a group of experts formed during a workshop organized jointly by the Multidisciplinary European Low Dose Initiative (MELODI) and the European Radioecology Alliance (ALLIANCE) associations to present the AOP approach and tools. The work presents a series of taxon-specific case studies that were used to identify relevant empirical evidence, identify common AOP components and propose a set of consensus AOPs that could be organized into an AOP network with broader taxonomic applicability. Conclusion Expert consultation led to the identification of key biological events and description of causal linkages between ionizing radiation, reproductive impairment and reduction in population fitness. The study characterized the knowledge domain of taxon-specific AOPs, identified knowledge gaps pertinent to reproductive-relevant AOP development and reflected on how AOPs could assist applications in radiation (radioecological) research, environmental health assessment, and radiological protection. Future advancement and consolidation of the AOPs is planned to include structured weight of evidence considerations, formalized review and critical assessment of the empirical evidence prior to formal submission and review by the OECD sponsored AOP development program

    Effects on ecosystems at Chernobyl and Fukushima: remaining controversies and future research challenges

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    The current knowledge about the radiation effects on wildlife was used in the last decade to develop appropriate radiological environmental impact assessment tools and to derive the associated protection benchmarks. For example, dose rates for reference animal or plants within which there is likely to be some chance of the occurrence of deleterious effects (DCRLs, derived consideration reference levels) were suggested from 0.1-1 to 10-100 mGy day-1, accounting for the variation in sensitivity of the considered wildlife group (ICRP, 2008). However, most of the available knowledge used to derive such benchmarks is related to the risk to individual organisms, whereas populations, ecological function and structure, and the preservation of biodiversity are more relevant from a management perspective and should be the focus of future studies. On the other hand, there is currently a considerable scientific disagreement on the actual extent of the radiation effects on wildlife populations in contaminated areas. Many studies have reported no significant effects of radiation on wildlife (e.g., in the Chernobyl and Fukushima exclusion zones), whereas others reported significant radiation effects on different wildlife populations at very low dose rates (below natural background exposure). This questions the robustness, the representativeness, and the scientific consensus of actual diagnostic tools with regard to the long-term consequences of radiation exposure on non-human biota and ecosystems. This controversy has major implications for the robustness and the credibility of the system of radiation protection and resolving it would be a major game changer (cf. joint roadmap for radiation protection research, EJP CONCERT D3.7). The robustness of radiological environmental impact assessment can be improved by an actual understanding of ionising radiation effects on key ecosystem processes under realistic conditions, associated with a robust exposure assessment and considering other stress factors. The presentation will give some recent illustrations from the Alliance members research and will conclude with the major issues and research priorities to resolve the controversy with regard to the effects on wildlife reported in the Chernobyl and Fukushima exclusion zone. The Alliance belief is that a re-interpretation and achievement of robust, consensus-based data on the long-term ecological effects attributable to radiation in those emblematic contaminated territories would have a very significant impact on the confidence and credibility level of the radiation protection of the environment (e.g., robustness of ‘no-effect’ benchmark dose-rates)

    From tangled banks to toxic bunnies; a reflection on the issues involved in developing an ecosystem approach for environmental radiation protection

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    The objective of this paper is to present the results of discussions at a workshop held as part of the International Congress of Radiation Research (Environmental Health stream) in Manchester UK, 2019. The main objective of the workshop was to provide a platform for radioecologists to engage with radiobiologists to address major questions around developing an Ecosystem approach in radioecology and radiation protection of the environment. The aim was to establish a critical framework to guide research that would permit integration of a pan-ecosystem approach into radiation protection guidelines and regulation for the environment. The conclusions were that the interaction between radioecologists and radiobiologists is useful in particular in addressing field versus laboratory issues where there are issues and challenges in designing good field experiments and a need to cross validate field data against laboratory data and vice versa. Other main conclusions were that there is a need to appreciate wider issues in ecology to design good approaches for an ecosystems approach in radioecology and that with the capture of 'Big Data', novel tools such as machine learning can now be applied to help with the complex issues involved in developing an ecosystem approach

    Current evidence for a role of epigenetic mechanisms in response to ionizing radiation in an ecotoxicological context

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    International audienceThe issue of potential long-term or hereditary effects for both humans and wildlife exposed to low doses (or doserates) of ionising radiation is a major concern. Chronic exposure to ionising radiation, defined as an exposure over alarge fraction of the organism’s lifespan or even over several generations, can possibly have consequences in theprogeny. Recent work has begun to show that epigenetics plays an important role in adaptation of organismschallenged to environmental stimulae. Changes to so-called epigenetic marks such as histone modifications, DNAmethylation and non-coding RNAs result in altered transcriptomes and proteomes, without directly changing the DNAsequence. Moreover, some of these environmentally-induced epigenetic changes tend to persist over generations, andthus, epigenetic modifications are regarded as the conduits for environmental influence on the genome. Here, wereview the current knowledge of possible involvement of epigenetics in the cascade of responses resulting fromenvironmental exposure to ionising radiation. In addition, from a comparison of lab and field obtained data, weinvestigate evidence on radiation-induced changes in the epigenome and in particular the total or locus specific levelsof DNA methylation. The challenges for future research and possible use of changes as an early warning (biomarker)of radiosensitivity and individual exposure is discussed. Such a biomarker could be used to detect and betterunderstand the mechanisms of toxic action and inter/intra-species susceptibility to radiation within an environmentalrisk assessment and management context

    Detection of body postures and movements in ambulatory adults with cerebral palsy: a novel and valid measure of physical behaviour

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    BACKGROUND: Accurate measurement of physical behaviour is paramount to better understand lifestyle, health, and functioning, particularly in adults with physical disability as they may be at higher risk of sedentary lifestyle and subsequent negative health consequences. This study aimed: 1) to evaluate the criterion validity of a novel and clinically applicable activity monitor (AM, Activ8), in the detection of body postures and movements in adults with spastic cerebral palsy (CP); and 2) to evaluate the extent that the AM's positioning affects validity. METHODS: In this cross-sectional study, 14 ambulatory adults with CP [9 men; mean (SD) age, 35.4 (13.1) years] performed standardized activities while wearing three Activ8 monitors - frontolateral thigh (primary position), frontal thigh, and pant pocket - and being video recorded (criterion measure). AM activity output was compared to synchronized video recordings. Absolute (seconds) and relative [(video time-AM time)/mean time, %] time differences between methods were calculated. Relative time differences of < 10% were indicative of good validity. Comparison of AM attachment positions was completed using Spearman Rho correlation coefficients and Meng's tests. RESULTS: Criterion validity of the AM (frontolateral thigh) was good (average relative time differences: 0.25% for sitting, 4.69% for standing, 2.46% for walking, 1.96% for upright activity, 3.19% for cycling), except for running (34.6%). Spearman Rho correlation coefficients were greater between video/frontolateral thigh position than video/frontal thigh position and video/pant pocket position for body posture and movement categories sitting, standing, walking, and upright activity (p < 0.01 for all). CONCLUSIONS: The AM, positioned on the frontolateral thigh, demonstrated good criterion validity in ambulatory adults with CP. Though the Activ8 offers potential as an objective measure of physical activity, appropriate positioning is paramount for valid measurement

    The tubercular badger and the uncertain curve:- The need for a multiple stressor approach in environmental radiation protection.

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    This article presents the results of a workshop held in Stirling, Scotland in June 2018, called to examine critically the effects of low-dose ionising radiation on the ecosphere. The meeting brought together participants from the fields of low- and high-dose radiobiology and those working in radioecology to discuss the effects that low doses of radiation have on non-human biota. In particular, the shape of the low-dose response relationship and the extent to which the effects of low-dose and chronic exposure may be predicted from high dose rate exposures were discussed. It was concluded that high dose effects were not predictive of low dose effects. It followed that the tools presently available were deemed insufficient to reliably predict risk of low dose exposures in ecosystems. The workshop participants agreed on three major recommendations for a path forward. First, as treating radiation as a single or unique stressor was considered insufficient, the development of a multidisciplinary approach is suggested to address key concerns about multiple stressors in the ecosphere. Second, agreed definitions are needed to deal with the multiplicity of factors determining outcome to low dose exposures as a term can have different meanings in different disciplines. Third, appropriate tools need to be developed to deal with the different time, space and organisation level scales. These recommendations permit a more accurate picture of prospective risks.International Union of Radioecolog
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