Radiation adverse outcome pathways (AOPs) are on the horizon: advancing radiation protection through an international Horizon-Style exercise.

Purpose: The Adverse Outcome Pathway (AOP) framework, a systematic tool that can link available mechanistic data with phenotypic outcomes of relevance to regulatory decision-making, is being explored in areas related to radiation risk assessment. To examine the challenges including the use of AOPs to support the radiation protection community, an international horizon-style exercise was initiated through the Organisation for Economic Co-operation and Development Nuclear Energy Agency High-Level Group on Low Dose Research Radiation/Chemical AOP Joint Topical Group. The objective of the HSE was to facilitate the collection of ideas from a range of experts, to short-list a set of priority research questions that could, if answered, improve the description of the radiation dose-response relationship for low dose/dose-rate exposures, as well as reduce uncertainties in estimating the risk of developing adverse health outcomes following such exposures.

Ensuring robust radiological risk assessment for wildlife: insights from the International Atomic Energy Agency EMRAS and MODARIA programmes.

In response to changing international recommendations and national requirements, a number of assessment approaches, and associated tools and models, have been developed over the last circa 20 years to assess radiological risk to wildlife. In this paper, we summarise international intercomparison exercises and scenario applications of available radiological assessment models for wildlife to aid future model users and those such as regulators who interpret assessments. Through our studies, we have assessed the fitness for purpose of various models and tools, identified the major sources of uncertainty and made recommendations on how the models and tools can best be applied to suit the purposes of an assessment.

Best practices for predictions of radionuclide activity concentrations and total absorbed dose rates to freshwater organisms exposed to uranium mining/milling.

Predictions of radionuclide dose rates to freshwater organisms can be used to evaluate the radiological environmental impacts of releases from uranium mining and milling projects. These predictions help inform decisions on the implementation of mitigation measures. The objective of this study was to identify how dose rate modelling could be improved to reduce uncertainty in predictions to non-human biota.

An updated strategic research agenda for the integration of radioecology in the european radiation protection research.

The ALLIANCE Strategic Research Agenda (SRA) for radioecology is a living document that defines a long-term vision (20 years) of the needs for, and implementation of, research in radioecology in Europe. The initial SRA, published in 2012, included consultation with a wide range of stakeholders (Hinton et al., 2013).

The nitric oxide suppressed Arabidopsis mutants- Atnoa1 and Atnia1nia2noa1-2 produce nitric oxide in MS growth medium and on uranium exposure.

The mutants Atnoa1 and Atnia1nia2noa1-2 having a defective chloroplast developmental process, showed enhanced chlorophyll levels when they were grown on Murashige and Skoog (MS) medium and on exposure with uranium (U) on Hoagland medium. Thus we hypothesized that these mutants probably produced NO in MS medium and on exposure with U. Wild-type Col-0, Atnoa1, Atnia1nia2noa1-2 plants were cultured on modified Hoagland and 1/10 MS media and NO generation in the roots of these mutants was monitored using NO selective fluorescent dyes, DAF-2DA and Fl2E.

Exposure to ionizing radiation affects the growth of ectomycorrhizal fungi and induces increased melanin production and increased capacities of reactive oxygen species scavenging enzymes.

Ectomycorrhizal (EM) fungi form symbioses with dominant tree families in boreal, temperate and tropical ecosystems and are important drivers of ecosystem function. EM fungal hyphae extend over a large area making them susceptible to enhanced radiation levels from naturally occurring or anthropogenically originating radioisotopes in the rhizosphere. In this study, the in-vitro effects of ionizing radiation on the growth and biomass of EM fungi Suillus luteus, S.

Potential of higher plants, algae, and cyanobacteria for remediation of radioactively contaminated waters.

The potential of photosynthetic organisms to remediate radioactively contaminated water was evaluated for scenarios related to nuclear installations and included the following radionuclides: Cs, Cs, Cs, Sr, I, Pu, Am, Te/I, Co, Co, Cr, Ag, Mn, Sb, Fe, Zn, Zr, and Nb. An extensive literature review was undertaken leading to the creation of a database including more than 20,000 entries from over 100 references in which terrestrial and aquatic plants, macro- and microalgae, cyanobacteria and biosorbents derived from these organisms were used to clean water from these specific radionuclides or their stable isotopes. In a first phase, the remediation potential of the organisms and biosorbents was evaluated for the individual elements based on parameters such as plant uptake, removal percentage, and bioconcentration factor, and for two radionuclide mixtures based on the ability of the organisms/biosorbents to work under mixture conditions.

ALLIANCE perspectives on integration of humans and the environment into the system of radiological protection.

Risks posed by the presence of radionuclides in the environment require an efficient, balanced, and adaptable assessment for protecting exposed humans and wildlife, and managing the associated radiological risk. Exposure of humans and wildlife originate from the same sources releasing radionuclides to the environment. Environmental concentrations of radionuclides serve as inputs to estimate the dose to man, fauna, and flora, with transfer processes being, in essence, similar, which calls for a common use of transport models.

Sustainability and integration of radioecology-position paper.

This position paper gives an overview of how the COMET project (COordination and iMplementation of a pan-European instrumenT for radioecology, a combined Collaborative Project and Coordination and Support Action under the EC/Euratom 7th Framework Programme) contributed to the integration and sustainability of radioecology in Europe via its support to and interaction with the European Radioecology ALLIANCE. COMET built upon the foundations laid by the FP7 project STAR (Strategic Network for Integrating Radioecology) Network of Excellence in radioecology. In close association with the ALLIANCE, and based on the Strategic Research Agenda (SRA), COMET developed innovative mechanisms for joint programming and implementation of radioecological research.

COMET strongly supported the development and implementation of medium-term topical research roadmaps consistent with the ALLIANCE Strategic Research Agenda.

The ALLIANCE Strategic Research Agenda (SRA) initiated by the STAR Network of Excellence and integrated in the research strategy implemented by the COMET consortium, defines a long-term vision of the needs for, and implementation of, research in radioecology. This reference document, reflecting views from many stakeholders groups and researchers, serves as an input to those responsible for defining EU research call topics through the ALLIANCE SRA statement delivered each year to the EJP-CONCERT (2015-2020). This statement highlights a focused number of priorities for funding.

Lemna minor plants chronically exposed to ionising radiation: RNA-seq analysis indicates a dose rate dependent shift from acclimation to survival strategies.

Ecotoxicological research provides knowledge on ionising radiation-induced responses in different plant species. However, the sparse data currently available are mainly extracted from acute exposure treatments. To provide a better understanding of environmental exposure scenarios, the response to stress in plants must be followed in more natural relevant chronic conditions.

Foliar uptake of radiocaesium from irrigation water by paddy rice (Oryza sativa): an overlooked pathway in contaminated environments.

Flooded (paddy) rice (Oryza sativa) can take up ions from the irrigation water by foliar uptake via the exposed stem base. We hypothesised that the stem base uptake of radiocaesium (RCs) is a pathway for rice grown in RCs-contaminated environments. We developed a bi-compartmental device which discriminates the stem base from root RCs uptake from solutions, thereby using RCs isotopes ( Cs and Cs) with < 2% solution leak between the compartments.

Arabidopsis plants exposed to gamma radiation in two successive generations show a different oxidative stress response.

When terrestrial environments get contaminated with long-lived gamma emitting radionuclides, plants that grow in these contaminated areas are exposed to gamma radiation during consecutive generations. Therefore it is important to evaluate the gamma induced stress response in plants in and between generations. The objective of this research is to reveal differences at the level of the antioxidative stress response between generations with a different radiation history.

The IUR Forum: Worldwide Harmonisation of Networks to Support Integration of Scientific Knowledge and Consensus Development in Radioecology.

During the past decades, many specialised networks have formed to meet specific radioecological objectives, whether regional or sectorial (purpose-oriented). Regional networks deal with an array of radioecological issues related to their territories. Examples include the South Pacific network of radioecologists, and the European network of excellence in radioecology.

Agricultural land management options after the Chernobyl and Fukushima accidents: The articulation of science, technology, and society.

The options adopted for recovery of agricultural land after the Chernobyl and Fukushima accidents are compared by examining their technical and socio-economic aspects. The analysis highlights commonalities such as the implementation of tillage and other types of countermeasures and differences in approach, such as preferences for topsoil removal in Fukushima and the application of K fertilizers in Chernobyl. This analysis shows that the recovery approach needs to be context-specific to best suit the physical, social, and political environment.

Environmental risks of radioactive discharges from a low-level radioactive waste disposal site at Dessel, Belgium.

The potential radiological impact of releases from a low-level radioactive waste (Category A waste) repository in Dessel, Belgium on the local fauna and flora was assessed under a reference scenario for gradual leaching. The potential impact situations for terrestrial and aquatic fauna and flora considered in this study were soil contamination due to irrigation with contaminated groundwater from a well at 70 m from the repository, contamination of the local wetlands receiving the highest radionuclide flux after migration through the aquifer and contamination of the local river receiving the highest radionuclide flux after migration through the aquifer. In addition, an exploratory study was carried out for biota residing in the groundwater.

Variability of the soil-to-plant radiocaesium transfer factor for Japanese soils predicted with soil and plant properties.

Food chain contamination with radiocaesium (RCs) in the aftermath of the Fukushima accident calls for an analysis of the specific factors that control the RCs transfer. Here, soil-to-plant transfer factors (TF) of RCs for grass were predicted from the potassium concentration in soil solution (mK) and the Radiocaesium Interception Potential (RIP) of the soil using existing mechanistic models. The mK and RIP were (a) either measured for 37 topsoils collected from the Fukushima accident affected area or (b) predicted from the soil clay content and the soil exchangeable potassium content using the models that had been calibrated for European soils.

The first draft genome of the aquatic model plant Lemna minor opens the route for future stress physiology research and biotechnological applications.

Background: Freshwater duckweed, comprising the smallest, fastest growing and simplest macrophytes has various applications in agriculture, phytoremediation and energy production. Lemna minor, the so-called common duckweed, is a model system of these aquatic plants for ecotoxicological bioassays, genetic transformation tools and industrial applications. Given the ecotoxic relevance and high potential for biomass production, whole-genome information of this cosmopolitan duckweed is needed.

Rhizophagus irregularis MUCL 41833 can colonize and improve P uptake of Plantago lanceolata after exposure to ionizing gamma radiation in root organ culture.

Long-lived radionuclides such as (90)Sr and (137)Cs can be naturally or accidentally deposited in the upper soil layers where they emit β/γ radiation. Previous studies have shown that arbuscular mycorrhizal fungi (AMF) can accumulate and transfer radionuclides from soil to plant, but there have been no studies on the direct impact of ionizing radiation on AMF. In this study, root organ cultures of the AMF Rhizophagus irregularis MUCL 41833 were exposed to 15.

Characterizing dose response relationships: Chronic gamma radiation in Lemna minor induces oxidative stress and altered polyploidy level.

The biological effects and interactions of different radiation types in plants are still far from understood. Among different radiation types, external gamma radiation treatments have been mostly studied to assess the biological impact of radiation toxicity in organisms. Upon exposure of plants to gamma radiation, ionisation events can cause, either directly or indirectly, severe biological damage to DNA and other biomolecules.

Oxidative stress responses induced by uranium exposure at low pH in leaves of Arabidopsis thaliana plants.

Anthropogenic activities have led to a widespread uranium (U) contamination in many countries. The toxic effects of U at the cellular level have mainly been investigated at a pH around 5.5, the optimal pH for hydroponically grown plants.

Biological effects of α-radiation exposure by (241)Am in Arabidopsis thaliana seedlings are determined both by dose rate and (241)Am distribution.

Human activity has led to an increasing amount of radionuclides in the environment and subsequently to an increased risk of exposure of the biosphere to ionising radiation. Due to their high linear energy transfer, α-emitters form a threat to biota when absorbed or integrated in living tissue. Among these, (241)Am is of major concern due to high affinity for organic matter and high specific activity.

β-Radiation Stress Responses on Growth and Antioxidative Defense System in Plants: A Study with Strontium-90 in Lemna minor.

In the following study, dose dependent effects on growth and oxidative stress induced by β-radiation were examined to gain better insights in the mode of action of β-radiation induced stress in plant species. Radiostrontium (⁹⁰Sr) was used to test for β-radiation induced responses in the freshwater macrophyte Lemna minor. The accumulation pattern of 90Sr was examined for L.

Influence of nutrient medium composition on uranium toxicity and choice of the most sensitive growth related endpoint in Lemna minor.

Uranium (U) toxicity is known to be highly dependent on U speciation and bioavailability. To assess the impact of uranium on plants, a growth inhibition test was set up in the freshwater macrophyte Lemna minor. First growth media with different compositions were tested in order to find a medium fit for testing U toxicity in L.