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  • 1. Allan, Ian J.
    et al.
    Nilsson, Hans C.
    Tjensvoll, Ingrid
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Naes, Kristoffer
    Mobile passive samplers: Concept for a novel mode of exposure2011In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 159, no 10, p. 2393-2397Article in journal (Refereed)
    Abstract [en]

    Integrative passive sampling with devices such as semipermeable membrane devices generally relies on rigs for month-long static exposures in water. We evaluate here whether mobile exposures of passive samplers can provide reliable estimates of dissolved contaminant concentrations. Mobile exposures were obtained by towing samplers fastened to the end of a benthic trawl net. Significant and reproducible absorption of polycyclic aromatic hydrocarbons during 5 h-long deployments was made possible by high sampling rates resulting from high water turbulences during towing at 1.2-1.5 knots. Sampling rates (72-215 L d(-1)) estimated from the dissipation of performance reference compounds were supported by in situ calibration with samplers exposed for a 30 days in the vicinity of the test site. Higher fluoranthene and pyrene absorption in samplers exposed to the trawling-induced sediment plume could be attributed to desorption from re-suspended sediments. This mode of exposure has the potential to be used in monitoring programmes.

  • 2. Allan, Ian J.
    et al.
    Nilsson, Hans C.
    Tjensvoll, Ingrid
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Naes, Kristoffer
    PCDD/F release during benthic trawler-induced sediment resuspension2012In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 31, no 12, p. 2780-2787Article in journal (Refereed)
    Abstract [en]

    Benthic trawling can cause the resuspension of large amounts of sediments. Such regular practice in the Grenland fjord system in the south of Norway has the potential to affect the fate, movement, and bioavailability of sediment-associated polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). A novel mode of exposing passive sampling devices consisting of towing semipermeable membrane devices attached to the trawl net was used to gauge in situ changes in the freely dissolved concentration of PCDD/Fs on benthic trawlerinduced sediment resuspension. Significant accumulation of a number of PCDD/F congeners was observed despite the short (5?h) sampler exposure times. On average, a one order of magnitude increase in freely dissolved PCCD/F concentrations was seen within minutes of the sediment being resuspended. This observation was supported by similar changes in filtered PCDD/F concentrations measured by high-volume sampling prior to resuspension and in the sediment plume. Environ. Toxicol. Chem. 2012; 31: 27802787.

  • 3. Alonzo, Frederic
    et al.
    Hertel-Aas, Turid
    Real, Almudena
    Lance, Emilie
    Garcia-Sanchez, Laurent
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Vives i Baffle, Jordi
    Oughton, Deborah H.
    Garnier-Laplace, Jacqueline
    Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups2016In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 152, p. 46-59Article in journal (Refereed)
    Abstract [en]

    In this study, we modelled population responses to chronic external gamma radiation in 12 laboratory species (including aquatic and soil invertebrates, fish and terrestrial mammals). Our aim was to compare radiosensitivity between individual and population endpoints and to examine how internationally proposed benchmarks for environmental radioprotection protected species against various risks at the population level. To do so, we used population matrix models, combining life history and chronic radiotoxicity data (derived from laboratory experiments and described in the literature and the FRED ERICA database) to simulate changes in population endpoints (net reproductive rate R-0, asymptotic population growth rate lambda, equilibrium population size N-eq) for a range of dose rates. Elasticity analyses of models showed that population responses differed depending on the affected individual endpoint (juvenile or adult survival, delay in maturity or reduction in fecundity), the considered population endpoint (R-0, lambda or N-eq) and the life history of the studied species. Among population endpoints, net reproductive rate R-0 showed the lowest EDR10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 mu Gy h(-1) in the mouse Mus musculus to 38,000 mu Gy h(-1) in the fish Oryzias latipes. For several species, EDR10 for population endpoints were lower than the lowest EDR10 for individual endpoints. Various population level risks, differing in severity for the population, were investigated. Population extinction (predicted when radiation effects caused population growth rate lambda to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 mu Gy h(-1) in fish to 12,000 mu Gy h(-1) in soil invertebrates. A milder risk, that population growth rate lambda will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 mu Gy h(-1) in mammals to 1800 mu Gy h(-1) in soil invertebrates. These predictions suggested that proposed reference benchmarks from the literature for different taxonomic groups protected all simulated species against population extinction. A generic reference benchmark of 10 mu Gy h(-1) protected all simulated species against 10% of the effect causing population extinction. Finally, a risk of pseudo-extinction was predicted from 2.0 mu Gy h(-1) in mammals to 970 mu Gy h(-1) in soil invertebrates, representing a slight but statistically significant population decline, the importance of which remains to be evaluated in natural settings.

  • 4. Beresford, Nicholas A.
    et al.
    Wood, Michael D.
    Vives i Batlle, Jordi
    Yankovich, Tamara L.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Willey, Neil
    Making the most of what we have: application of extrapolation approaches in radioecological wildlife transfer models2016In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 151, p. 373-386Article in journal (Refereed)
    Abstract [en]

    We will never have data to populate all of the potential radioecological modelling parameters required for wildlife assessments. Therefore, we need robust extrapolation approaches which allow us to make best use of our available knowledge. This paper reviews and, in some cases, develops, tests and validates some of the suggested extrapolation approaches. The concentration ratio (CRproduct-diet or CRwo-diet) is shown to be a generic (trans-species) parameter which should enable the more abundant data for farm animals to be applied to wild species. An allometric model for predicting the biological half-life of radionuclides in vertebrates is further tested and generally shown to perform acceptably. However, to fully exploit allometry we need to understand why some elements do not scale to expected values. For aquatic ecosystems, the relationship between log10(a) (a parameter from the allometric relationship for the organism-water concentration ratio) and log(K-d) presents a potential opportunity to estimate concentration ratios using K-d values. An alternative approach to the CRwo-media model proposed for estimating the transfer of radionuclides to freshwater fish is used to satisfactorily predict activity concentrations in fish of different species from three lakes. We recommend that this approach (REML modelling) be further investigated and developed for other radionuclides and across a wider range of organisms and ecosystems. Ecological stoichiometry shows potential as an extrapolation method in radioecology, either from one element to another or from one species to another. Although some of the approaches considered require further development and testing, we demonstrate the potential to significantly improve predictions of radionuclide transfer to wildlife by making better use of available data.

  • 5.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Södertörn University, Sweden.
    Golz, Anna-Lea
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gustafsson, Kerstin
    Coastal Ecosystem Effects of Increased Summer Temperature and Contamination by the Flame Retardant HBCDD2017In: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 5, no 2, article id 18Article in journal (Refereed)
    Abstract [en]

    The combined effects of ocean warming and contaminants on marine ecosystems are poorly understood. In this study, we exposed model ecosystems comprising typical shallow coastal Baltic Sea communities to elevated temperature (+5 °C) and the flame retardant hexabromocyclododecane (HBCDD), both singly and in combination, for 13 days. Higher temperatures caused the release of PO4 from the sediment, which in turn stimulated the growth of the cyanobacteria Dolichospermum sp. This in turn led to an increase in the copepod Acartia bifilosa and other indirect effects in the plankton, interpreted as being caused by changes in predation, grazing, and competition. Elevated temperatures also stimulated benthic primary production and increased production of benthic mollusk larvae. Although increased temperature was the dominant driver of effects in these systems, HBCDD also appeared to have some effects, mainly in the zooplankton (both direct and indirect effects) and benthic meiofauna (an interactive effect with temperature). Although the study used model ecosystems, which are an approximation of field conditions, it highlights that interactive ecosystem effects between two stressors are possible and demonstrates the ecological and temporal complexity of such responses. Such unpredictable responses to warming and contaminants are a major challenge for ecosystem management to deal with multistressor situations in the Baltic Sea.

  • 6.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kapustka, Lawrence
    Barnthouse, Lawrence
    Brown, Justin
    Ciffroy, Philippe
    Forbes, Valery
    Geras'kin, Stanislav
    Kautsky, Ulrik
    Brechignac, Francois
    Using an Ecosystem Approach to complement protection schemes based on organism-level endpoints2014In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 136, p. 98-104Article in journal (Refereed)
    Abstract [en]

    Radiation protection goals for ecological resources are focussed on ecological structures and functions at population-, community-, and ecosystem-levels. The current approach to radiation safety for non-human biota relies on organism-level endpoints, and as such is not aligned with the stated overarching protection goals of international agencies. Exposure to stressors can trigger non-linear changes in ecosystem structure and function that cannot be predicted from effects on individual organisms. From the ecological sciences, we know that important interactive dynamics related to such emergent properties determine the flows of goods and services in ecological systems that human societies rely upon. A previous Task Group of the IUR (International Union of Radioecology) has presented the rationale for adding an Ecosystem Approach to the suite of tools available to manage radiation safety. In this paper, we summarize the arguments for an Ecosystem Approach and identify next steps and challenges ahead pertaining to developing and implementing a practical Ecosystem Approach to complement organism-level endpoints currently used in radiation safety.

  • 7.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kautsky, Ulrik
    Kumblad, Linda
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Ecological stoichiometry and multi element transfer in a coastal ecosystem2012In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 15, no 4, p. 591-603Article in journal (Refereed)
    Abstract [en]

    Energy (carbon) flows and element cycling are fundamental, interlinked principles explaining ecosystem processes. The element balance in components, interactions and processes in ecosystems (ecological stoichiometry; ES) has been used to study trophic dynamics and element cycling. This study extends ES beyond its usual limits of C, N, and P and examines the distribution and transfer of 48 elements in 16 components of a coastal ecosystem, using empirical and modeling approaches. Major differences in elemental composition were demonstrated between abiotic and biotic compartments and trophic levels due to differences in taxonomy and ecological function. Mass balance modeling for each element, based on carbon fluxes and element:C ratios, was satisfactory for 92.5% of all element similar to compartment combinations despite the complexity of the ecosystem model. Model imbalances could mostly be explained by ecological processes, such as increased element uptake during the spring algal bloom. Energy flows in ecosystems can thus realistically estimate element transfer in the environment, as modeled uptake is constrained by metabolic rates and elements available. The dataset also allowed us to examine one of the key concepts of ES, homeostasis, for more elements than is normally possible. The relative concentrations of elements in organisms compared to their resources did not provide support for the theory that autotrophs show weak homeostasis and showed that the strength of homeostasis by consumers depends on the type of element (for example, macroelement, trace element). Large-scale, multi-element ecosystem studies are essential to evaluate and advance the framework of ES and the importance of ecological processes.

  • 8.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Skipperud, Lindis
    Beresford, Nicholas A.
    Barnett, Catherine L.
    Vidal, Miquel
    Education and training in radioecology during the EU-COMET project-successes and suggestions for the future2018In: Journal of Radiological Protection, ISSN 0952-4746, E-ISSN 1361-6498, Vol. 38, no 1, p. 140-151Article in journal (Refereed)
    Abstract [en]

    The 2014 Strategic Research Agenda (SRA) for Radioecology identified the key challenge in education and training (E&T) as being 'to maintain and develop a skilled workforce in Europe and world-wide, through university candidates and professionals trained within radioecology' since 'scientific research in radioecology and application of that knowledge K requires scientists and workers with adequate competence and appropriate skills.' Radioecology is a multidisciplinary science and E&T is needed by both students and professionals within research, industry and radiation protection. In order to address these needs, the EU COMET project has developed an E&T web platform and arranged a number of field courses, training courses, PhD and MSc courses, refresher courses and workshops, drawing on the COMET consortium to assemble relevant experts. In addition, COMET has been engaged in discussions with stakeholders for more long-term solutions to maintain the sustainability of radioecology E&T after the end of the project. Despite much progress in some areas, many of the challenges outlined in the 2014 SRA remain, mainly due to the lack of sustainable dedicated funding. Future plans within the ALLIANCE radioecology platform and the CONCERT-European Joint Programme for the Integration of Radiation Protection Research must urgently address this lack of sustainability if radioecological competence is to be maintained in Europe.

  • 9.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Södertörn University College, Sweden.
    Strid, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    von Stedingk, Hans
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gustafsson, Kerstin
    Effects of benthos, temperature, and dose on the fate of hexabromocyclododecane in experimental coastal ecosystems2015In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 34, no 6, p. 1246-1257Article in journal (Refereed)
    Abstract [en]

    The authors studied the fate of the brominated flame retardant hexabromocyclododecane (HBCDD) added in a particulate suspension to experimental ecosystems assembled from brackish (Baltic Sea) coastal bays. Two experiments examined how benthic macrofauna (over 21 d) and increased temperature (14 d) affected HBCDD concentrations and fractionation of , , and diastereomers in the water, sediment, and biota. A third experiment run over 3 seasons (231 d), studied the effect of HBCDD dose on the same endpoints. In all treatments of the 3 experiments, HBCDD partitioned mainly to the sediment, and this proportion increased with time. Presence of macrofauna tended to increase the HBCDD concentration in the sediment and decreased its concentration in the water. Increased temperature (+5 degrees C) decreased the amount of HBCDD in sediment and water but not in the filter- and deposit-feeding infaunal bivalves (Macoma balthica). The partitioning between water, sediment, and biota was not concentration dependent. In all treatments, sediment became enriched in -HBCDD, M. balthica in -HBCDD, and water in - and -HBCDD. Bioaccumulation of HBCDD in M. balthica was high in all experiments (log biota-sediment accumulation factor [BSAF] > 1.25), the diastereomer contributing the most (log BSAF 2.1-5.2). There is a risk of trophic transfer of HBCDD from benthic to pelagic food webs, as well as secondary poisoning of marine consumers. Environ Toxicol Chem 2015;34:1246-1257.

  • 10.
    Bradshaw, Clare
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Tjensvoll, Ingrid
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Sköld, M.
    Allan, I. J.
    Molvaer, J.
    Magnusson, J.
    Naes, K.
    Nilsson, H. C.
    Bottom trawling resuspends sediment and releases bioavailable contaminants in a polluted fjord2012In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 170, p. 232-241Article in journal (Refereed)
    Abstract [en]

    Sediments are sinks for contaminants in the world's oceans. At the same time, commercial bottom trawling is estimated to affect around 15 million km(2) of the world's seafloor every year. However, few studies have investigated whether this disturbance remobilises sediment-associated contaminants and, if so, whether these are bioavailable to aquatic organisms. This field study in a trawled contaminated Norwegian fjord showed that a single 1.8 km long trawl pass created a 3-5 million m(3) sediment plume containing around 9 t contaminated sediment; ie. 200 g dw m(-2) trawled, equivalent to c. 10% of the annual gross sedimentation rate. Substantial amounts of PCDD/Fs and non-ortho PCBs were released from the sediments, likely causing a semi-permanent contaminated sediment suspension in the bottom waters. PCDD/Fs from the sediments were also taken up by mussels which, during one month, accumulated them to levels above the EU maximum advised concentration for human consumption.

  • 11. Bréchignac, Francois
    et al.
    Oughton, Deborah
    Mays, Claire
    Barnthouse, Lawrence
    Beasley, James C.
    Bonisoli-Alquati, Andrea
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Brown, Justin
    Dray, Stéphane
    Geras'kin, Stanislav
    Glenn, Travis
    Higley, Kathy
    Ishida, Ken
    Kapustka, Lawrence
    Kautsky, Ulrik
    Kuhne, Wendy
    Lynch, Michael
    Mappes, Tapio
    Mihok, Steve
    Møller, Anders P.
    Mothersill, Carmel
    Mousseau, Timothy A.
    Otaki, Joji M.
    Pryakhin, Evgeny
    Rhodes, Olin E.
    Salbu, Brit
    Strand, Per
    Tsukada, Hirofumi
    Addressing ecological effects of radiation on populations and ecosystems to improve protection of the environment against radiation: Agreed statements from a Consensus Symposium2016In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 158, p. 21-29Article, review/survey (Refereed)
    Abstract [en]

    This paper reports the output of a consensus symposium organized by the International Union of Radioecology in November 2015. The symposium gathered an academically diverse group of 30 scientists to consider the still debated ecological impact of radiation on populations and ecosystems. Stimulated by the Chernobyl and Fukushima disasters' accidental contamination of the environment, there is increasing interest in developing environmental radiation protection frameworks. Scientific research conducted in a variety of laboratory and field settings has improved our knowledge of the effects of ionizing radiation on the environment. However, the results from such studies sometimes appear contradictory and there is disagreement about the implications for risk assessment. The Symposium discussions therefore focused on issues that might lead to different interpretations of the results, such as laboratory versus field approaches, organism versus population and ecosystemic inference strategies, dose estimation approaches and their significance under chronic exposure conditions. The participating scientists, from across the spectrum of disciplines and research areas, extending also beyond the traditional radioecology community, successfully developed a constructive spirit directed at understanding discrepancies. From the discussions, the group has derived seven consensus statements related to environmental protection against radiation, which are supplemented with some recommendations. Each of these statements is contextualized and discussed in view of contributing to the orientation and integration of future research, the results of which should yield better consensus on the ecological impact of radiation and consolidate suitable approaches for efficient radiological protection of the environment.

  • 12. Erichsen, Anders Christian
    et al.
    Konovalenko, Lena
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Mohlenberg, Flemming
    Closter, Rikke Margrethe
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Aquilonius, Karin
    Kautsky, Ulrik
    Radionuclide Transport and Uptake in Coastal Aquatic Ecosystems: A Comparison of a 3D Dynamic Model and a Compartment Model2013In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 42, no 4, p. 464-475Article in journal (Refereed)
    Abstract [en]

    In safety assessments of underground radioactive waste repositories, understanding radionuclide fate in ecosystems is necessary to determine the impacts of potential releases. Here, the reliability of two mechanistic models (the compartmental K-model and the 3D dynamic D-model) in describing the fate of radionuclides released into a Baltic Sea bay is tested. Both are based on ecosystem models that simulate the cycling of organic matter (carbon). Radionuclide transfer is linked to adsorption and flows of carbon in food chains. Accumulation of Th-230, Cs-135, and Ni-59 in biological compartments was comparable between the models and site measurements despite differences in temporal resolution, biological state variables, and partition coefficients. Both models provided confidence limits for their modeled concentration ratios, an improvement over models that only estimate means. The D-model enables estimates at high spatio-temporal resolution. The K-model, being coarser but faster, allows estimates centuries ahead. Future developments could integrate the two models to take advantage of their respective strengths.

  • 13. Hinton, T. G.
    et al.
    Garnier-Laplace, J.
    Vandenhove, H.
    Dowdall, M.
    Adam-Guillermin, C.
    Alonzo, F.
    Barnett, C.
    Beaugelin-Seiller, K.
    Beresford, N. A.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Brown, J.
    Eyrolle, F.
    Fevrier, L.
    Gariel, J. -C
    Gilbin, R.
    Hertel-Aas, T.
    Horemans, N.
    Howard, B. J.
    Ikaheimonen, T.
    Mora, J. C.
    Oughton, D.
    Real, A.
    Salbu, B.
    Simon-Cornu, M.
    Steiner, M.
    Sweeck, L.
    Vives i Batlle, J.
    An invitation to contribute to a strategic research agenda in radioecology2013In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 115, p. 73-82Article in journal (Refereed)
    Abstract [en]

    With intentions of integrating a portion of their respective research efforts into a trans-national programme that will enhance radioecology, eight European organisations recently formed the European Radioecology ALLIANCE (www.er-alliance.org). The ALLIANCE is an Association open to other organisations throughout the world with similar interests in promoting radioecology. The ALLIANCE members recognised that their shared radioecological research could be enhanced by efficiently pooling resources among its partner organizations and prioritising group efforts along common themes of mutual interest. A major step in this prioritisation process was to develop a Strategic Research Agenda (SRA). An EC-funded Network of Excellence in Radioecology, called STAR (Strategy for Allied Radioecology), was formed, in part, to develop the SRA. This document is the first published draft of the SRA. The SRA outlines a suggested prioritisation of research topics in radioecology, with the goal of improving research efficiency and more rapidly advancing the science. It responds to the question: What topics, if critically addressed over the next 20 years, would significantly advance radioecology? The three Scientific Challenges presented within the SRA, with their 15 associated research lines, are a strategic vision of what radioecology can achieve in the future. Meeting these challenges will require a directed effort and collaboration with many organisations the world over. Addressing these challenges is important to the advancement of radioecology and in providing scientific knowledge to decision makers. Although the development of the draft SRA has largely been a European effort, the hope is that it will initiate an open dialogue within the international radioecology community and its stakeholders. This is an abbreviated document with the intention of introducing the SRA and inviting contributions from interested stakeholders. Critique and input for improving the SRA are welcomed via a link on the STAR website (www.star-radioecology.org).

  • 14.
    Jaeschke, Benedict C.
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bioaccumulation of tritiated water in phytoplankton and trophic transfer of organically bound tritium to the blue mussel, Mytilus edulis2013In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 115, p. 28-33Article in journal (Refereed)
    Abstract [en]

    Large releases of tritium are currently permitted in coastal areas due to assumptions that it rapidly disperses in the water and has a low toxicity due to its low energy emissions. This paper presents a laboratory experiment developed to identify previously untested scenarios where tritium may concentrate or transfer in biota relevant to Baltic coastal communities. Phytoplankton populations of Dunaliella tertiolecta and Nodularia spumigena were exposed at different growth-stages, to tritiated water (HTO; 10 MBq l(-1)). Tritiated D. tertiolecta was then fed to mussels, Mytilus edulis, regularly over a period of three weeks. Activity concentrations of phytoplankton and various tissues from the mussel were determined. Both phytoplankton species transformed HTO into organically-bound tritium (OBT) in their tissues. D. tertiolecta accumulated significantly more tritium when allowed to grow exponentially in HTO than if it had already reached the stationary growth phase; both treatments accumulated significantly more than the corresponding treatments of N. spumigena. No effect of growth phase on bioaccumulation of tritium was detectable in N. spumigena following exposure. After mussels were given 3 feeds of tritiated D. tertiolecta, significant levels of tritium were detected in the tissues. Incorporation into most mussel tissues appeared to follow a linear relationship with number of tritiated phytoplankton feeds with no equilibrium, highlighting the potential for biomagnification. Different rates of incorporation in species from a similar functional group highlight the difficulties in using a 'representative' species for modelling the transfer and impact of tritium. Accumulations of organic tritium into the mussel tissues from tritiated-phytoplankton demonstrate an environmentally relevant transfer pathway of tritium even when water-concentrations are reduced, adding weight to the assertion that organically bound tritium acts as a persistent organic pollutant. The persistence, potential for biomagnification and the increased toxicity of organic tritium increases the potential impact on the environment following a release of HTO; current legislation does not adequately take into account the nature of organic forms of tritium and therefore may be underestimating accumulation and toxic effect of tritium in the environment. Such information is necessary to accurately assess the distribution of tritium following routine releases, and to adequately protect the environment and humans.

  • 15.
    Jaeschke, Benedict C.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Norwegian University of Life Sciences (NMBU), Norway.
    Lind, O. C.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Salbu, B.
    Retention of radioactive particles and associated effects in the filter-feeding marine mollusc Mytilus edulis2015In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 502, p. 1-7Article in journal (Refereed)
    Abstract [en]

    Radioactive particles are aggregates of radioactive atoms that may contain significant activity concentrations. They have been released into the environment from nuclear weapons tests, and from accidents and effluents associated with the nuclear fuel cycle. Aquatic filter-feeders can capture and potentially retain radioactive particles, which could then provide concentrated doses to nearby tissues. This study experimentally investigated the retention and effects of radioactive particles in the blue mussel, Mytilus edulis. Spent fuel particles originating from the Dounreay nuclear establishment and collected in the field, comprised a U and Al alloy containing fission products such as Cs-137 and Sr-90/Y-90. Particles were introduced into mussels in suspension with plankton-food or through implantation in the extrapallial cavity. Of the particles introduced with food, 37% were retained for 70 h, and were found on the siphon or gills, with the notable exception of one particle that was ingested and found in the stomach. Particles not retained seemed to have been actively rejected and expelled by the mussels. The largest and most radioactive particle (estimated dose rate 3.18 +/- 0.06 Gy h(-1)) induced a significant increase in Comet tail-DNA %. In one case this particle caused a large white mark (suggesting necrosis) in the mantle tissue with a simultaneous increase in micronucleus frequency observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by radiation from the retained particle. White marks found in the tissue were attributed to ionising radiation and physical irritation. The results indicate that current methods used for risk assessment, based upon the absorbed dose equivalent limit and estimating the no-effect dose are inadequate for radioactive particle exposures. Knowledge is lacking about the ecological implications of radioactive particles released into the environment, for example potential recycling within a population, or trophic transfer in the food chain.

  • 16.
    Jaeschke, Benedict
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Lind, Ole Christian
    University of Life Sciences (UMB), Norway.
    Bradshaw, Clare
    Stockholm University, Faculty of Science.
    Salbu, Brit
    University of Life Sciences (UMB), Norway .
    Retention of radioactive particles and associated effects in the filter-feeding marine mollusc Mytilus edulisManuscript (preprint) (Other academic)
    Abstract [en]

    Radioactive particles are aggregates of radioactive atoms formed by, e.g., condensation or precipitation of radionuclides or breakdown of larger radioactive materials, and can contain significant radioactivity. They have been released into the environment from nuclear weapons tests, and from accidents and effluents within the fuel nuclear cycle.

    Aquatic filter feeders can be expected to take up and potentially retain radioactive particles, which could then provide concentrated localised doses to nearby tissues. Despite the high potential for accumulation and the potency of radioactive exposure, studies of the retention of radioactive particles in filter feeders are scarce. This study experimentally investigated the retention and effects of radioactive particles in the blue mussel, Mytilus edulis.

    The spent fuel particles, collected in the field, comprised of a U and Al alloy containing fission products such as 137Cs and 90Sr/90Y. The particles were introduced into mussels in suspension with plankton food or through implantation under the mantle tissue. Induced effects of the particle exposure were measured using micronucleus and Comet assays on haemocytes. Of those particles introduced with food, 37.5 % were retained for 70 h, and were found in the siphons and gills, with the notable exception of one particle that was ingested, found in the stomach. Those not retained seemed to have been actively rejected by the mussels. In several cases where particles were retained or implanted, white marks suggesting necrosis were seen in the tissues near the particles; these are thought to be caused by radiation and physical irritation. The largest and most radioactive particle (estimated dose rate 3.18 ±0.06 Gy.h-1) caused the largest such mark in the mantle tissue; in this case, increased micronucleus frequency and Comet tail DNA % was also observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by the high dose particle.

    The results showed that radioactive particles can potentially be retained by blue mussels and retained high activity particles can potentially induce negative effects, particularly in tissues close to such particles. Thus, current methods which are used for risk assessment that calculate “no-effect dose” estimates and are based upon the absorbed dose equivalent limit are inadequate for radioactive particle exposures. In addition, knowledge is lacking about the ecological implications of radioactive particles, for example potential recycling within a population, or trophic transfer in the food chain.

  • 17.
    Konovalenko, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Andersson, Eva
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, Ulrik
    Transfer of 13 elements in a lake using a process-based ecosystem modelManuscript (preprint) (Other academic)
  • 18.
    Konovalenko, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Andersson, E.
    Kautsky, U.
    Application of an ecosystem model to evaluate the importance of different processes and food web structure for transfer of 13 elements in a shallow lake2017In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 169, p. 85-97Article in journal (Refereed)
    Abstract [en]

    In environmental risk assessments of nuclear waste, there is need to estimate the potential risks of a large number of radionuclides over a long time period during which the environment is likely to change. Usually concentration ratios (CRs) are used to calculate the activity concentrations in organisms. However, CRs are not available for all radionuclides and they are not easily scalable to the varying environment. Here, an ecosystem transport model of elements, which estimates concentrations in organisms using carbon flows and food transfer instead of CR is presented. It is a stochastic compartment model developed for Lake Eckarfjarden at Forsmark in Sweden. The model was based on available data on carbon circulation, physical and biological processes from the site and identifies 11 functional groups of organisms. The ecosystem model was used to estimate the environmental transfer of 13 elements (Al, Ca, Cd, CI, Cs, I, Ni, Nb, Pb, Se, Sr, Th, U) to various aquatic organisms, using element-specific distribution coefficients for suspended particles (K-d PM) and upper sediment (K-d sed), and subsequent transfer in the foodweb. The modelled CRs for different organism groups were compared with measured CRs from the lake and literature data, and showed good agreement for many elements and organisms, particularly for lower trophic levels. The model is, therefore, proposed as an alternative to measured CR, though it is suggested to further explore active uptake, assimilation and elimination processes to get better correspondence for some of the elements. The benthic organisms (i.e. bacteria, microphytobenthos and macroalgae) were identified as more important than pelagic organisms for transfer of elements to top predators. The element transfer model revealed that most of the radionuclides were channelled through the microbial loop, despite the fact that macroalgae dominated the carbon fluxes in this lake. Thus, element-specific adsorption of elements to the surface of aquatic species, that may be food sources for organisms at higher trophic levels, needs to be considered in combination with generic processes described by carbon fluxes.

  • 19.
    Konovalenko, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Andersson, E.
    Lindqvist, Dennis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kautsky, U.
    Evaluation of factors influencing accumulation of stable Sr and Cs in lake and coastal fish2016In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 160, p. 64-79Article in journal (Refereed)
    Abstract [en]

    As a result of nuclear accidents and weapons tests, the radionuclides Cs-137 and Sr-90 are common contaminants in aquatic ecosystems. Concentration ratios (CR) based on concentrations of stable Cs and Sr in biota and media are used for the estimation of transfer of their radioisotopes for radiation dose calculations in environmental and human safety assessments. Available element-specific CRs vary by over an order of magnitude for similar organisms, thus affecting the dose estimates proportionally. The variation could be reduced if they were based on a better understanding of the influence of the underlying data and how that affects accumulation and potential biomagnification of stable Cs and Sr in aquatic organisms. For fish, relationships have been identified between water concentrations of K and CR of Cs-137, and between water concentrations of Ca and CR of Sr-90. This has not been confirmed for stable Cs and Sr in European waters. In this study, we analysed an existing dataset for stable Cs and Sr, as well as K and Ca, in four Swedish lakes and three Baltic Sea coastal areas, in order to understand the behaviour of these elements and their radioisotopes in these ecosystems. We found significant seasonal variations in the water concentrations of Cs, Sr, K and Ca, and in electrical conductivity (EC), especially in the lakes. CR values based on measurements taken at single or few time points may, therefore, be inaccurate or introduce unnecessarily large variation into risk assessments. Instead, we recommend incorporating information about the underlying variation in water concentrations into the CR calculations, for example by using the variation of the mean. The inverse relationships between fish CRCs -[K](water) and fish CRSr-[Ca](water), confirmed that stable Cs and Sr follow the same trends as their radioisotopes. Thus, they can be used as proxies when radioisotope data are lacking. EC was also strongly correlated with K and Ca concentrations in the water and could potentially be used as a quick and cost-effective method to estimate water chemistry to obtain less variable CR. We also recommend some simple improvements to data collection that would greatly enhance our ability to understand Cs and Sr uptake by fish.

  • 20.
    Konovalenko, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kumblad, Linda
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kautsky, U.
    Radionuclide transfer in marine coastal ecosystems, a modelling study using metabolic processes and site data2014In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 133, p. 48-59Article in journal (Refereed)
    Abstract [en]

    This study implements new site-specific data and improved process-based transport model for 26 elements (Ac, Ag, Am, Ca, Cl, Cm, Cs, Ho, I, Nb, Ni, Np, Pa, Pb, Pd, Po, Pu, Ra, Se, Sm, Sn, Sr, Tc, Th, U, Zr), and validates model predictions with site measurements and literature data. The model was applied in the safety assessment of a planned nuclear waste repository in Forsmark, Oregrundsgrepen (Baltic Sea). Radionuclide transport models are central in radiological risk assessments to predict radionuclide concentrations in biota and doses to humans. Usually concentration ratios (CRs), the ratio of the measured radionuclide concentration in an organism to the concentration in water, drive such models. However, CRs vary with space and time and CR estimates for many organisms are lacking. In the model used in this study, radionuclides were assumed to follow the circulation of organic matter in the ecosystem and regulated by radionuclide-specific mechanisms and metabolic rates of the organisms. Most input parameters were represented by log-normally distributed probability density functions (PDFs) to account for parameter uncertainty. Generally, modelled CRs for grazers, benthos, zooplankton and fish for the 26 elements were in good agreement with site-specific measurements. The uncertainty was reduced when the model was parameterized with site data, and modelled CRs were most similar to measured values for particle reactive elements and for primary consumers. This study clearly demonstrated that it is necessary to validate models with more than just a few elements (e.g. Cs, Sr) in order to make them robust. The use of PDFs as input parameters, rather than averages or best estimates, enabled the estimation of the probable range of modelled CR values for the organism groups, an improvement over models that only estimate means. Using a mechanistic model that is constrained by ecological processes enables (i) the evaluation of the relative importance of food and water uptake pathways and processes such as assimilation and excretion, (ii) the possibility to extrapolate within element groups (a common requirement in many risk assessments when initial model parameters are scarce) and (iii) predictions of radionuclide uptake in the ecosystem after changes in ecosystem structure or environmental conditions. These features are important for the longterm (>1000 year) risk assessments that need to be considered for a deep nuclear waste repository.

  • 21.
    Kumblad, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Element composition of biota, water and sediment in the Forsmark area, Baltic Sea: Concentrations, bioconcentration factors and partitioning coefficients (Kd) of 48 elements2008Report (Other academic)
  • 22.
    Kumblad, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Bradshaw, Clare
    Gilek, Michael
    Södertörn University College.
    Bioaccumulation of Cr-51, Ni-63 and C-14 in Baltic Sea benthos2005In: Environmental Pollution, ISSN 1873-6424, Vol. 134, no 1, p. 45-56Article in journal (Refereed)
    Abstract [en]

    The Baltic Sea is a species-poor, semi-enclosed, brackish sea, whose sediments contain a wide range of contaminants, including sediment-associated metals and radionuclides. In this study, we have examined and compared bioaccumulation kinetics and assimilation efficiencies of sediment-associated 51Cr, 63Ni and 14C in three key benthic invertebrates (the deposit-feeding Monoporeia affinis, the facultative deposit-feeding Macoma baltica, and the omnivorous Halicryptus spinulosus). Our results demonstrate that (i) all radionuclides were accumulated, (ii) the different radionuclides were accumulated to various extents, (iii) small changes in organic carbon concentration can influence the accumulation, and (iv) the degree of accumulation differed only slightly between species. These processes, together with sediment resuspension and bioturbation, may remobilise trace metals from the sediment to the water and to higher trophic levels, and therefore should be taken into account in exposure models and ERAs.

    Bioaccumulation of radioisotopes in Baltic Sea benthos has important implications for contaminant transfer and exposure.

  • 23. Lindborg, T
    et al.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Löfgren, A
    Söderbäck, B
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kautsky, Ulrik
    A strategy for describing the biosphere at candidate sites for repositories of nuclear waste: Linking ecosystem and landscape modeling2006In: Ambio, Vol. 35, no 8, p. 418-424Article in journal (Refereed)
  • 24.
    Nascimento, Francisco J. A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Direct and indirect effects of ionizing radiation on grazer-phytoplankton interactions2016In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 155, p. 63-70Article in journal (Refereed)
    Abstract [en]

    Risk assessment of exposure to radionuclides and radiation does not usually take into account the role of species interactions. We investigated how the transfer of carbon between a primary producer, Raphidocelis subcapitata, and a consumer, Daphnia magna, was affected by acute exposure to gamma radiation. In addition to unexposed controls, different treatments were used where: a) only D. magna (Z treatment); b) only R. subcapitata (P treatment) and c) both D. magna and R. subcapitata (ZP treatment) were exposed to one of three acute doses of gamma radiation (5, 50 and 100 Gy). We then compared differences among treatments for three endpoints: incorporation of carbon by D. magna, D. magna growth and R. subcapitata densities. Carbon incorporation was affected by which combination of species was irradiated and by the radiation dose. Densities of R. subcapitata at the end of the experiment were also affected by which species had been exposed to radiation. Carbon incorporation by D. magna was significantly lower in the Z treatment, indicating reduced grazing, an effect stronger with higher radiation doses, possibly due to direct effects of gamma radiation. Top-down indirect effects of this reduced grazing were also seen as R. subcapitata densities increased in the Z treatment due to decreased herbivory. The opposite pattern was observed in the P treatment where only R. subcapitata was exposed to gamma radiation, while the ZP treatment showed intermediate results for both endpoints. In the P treatments, carbon incorporation by D. magna was significantly higher than in the other treatments, suggesting a higher grazing pressure. This, together with direct effects of gamma radiation on R. subcapitata, probably significantly decreased phytoplankton densities in the P treatment. Our results highlight the importance of taking into account the role of species interactions when assessing the effects of exposure to gamma radiation in aquatic ecosystems.

  • 25.
    Nascimento, Francisco J. A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Svendsen, Claus
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Combined Effects from gamma Radiation and Fluoranthene Exposure on Carbon Transfer from Phytoplankton to Zooplankton2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 17, p. 10624-10631Article in journal (Refereed)
    Abstract [en]

    Risk assessment does not usually take into account mixtures of contaminants, thus potentially under- or overestimating environmental effects. We investigated how the transfer of carbon between a primary producer, Pseudokirchneriella subcapitata, and a consumer, Daphnia magna, is affected by acute exposure of gamma radiation (GR) in combination with the polycyclic aromatic hydrocarbon fluoranthene (FA). We exposed D. magna to five concentrations of FA and five acute doses of GR as single contaminants and in nine binary combinations. We compared the observed data for three end points (incorporation of carbon by D. magna, D. magna ingestion rates, and growth) to the predicted joint effects of the mixed stressors based on the independent action (IA) concept. There were deviations from the IA predictions, especially for ingestion rates and carbon incorporation by D. magna, where antagonistic effects were observed at the lower doses, while synergism was seen at the highest doses. Our results highlight the importance of investigating the effects of exposure to GR in a multistressor context. In mixtures of GR and FA, the IA-predicted effects seem to be conservative as antagonism between the two stressors was the dominant pattern, possibly due to stimulation of cellular antioxidative stress mechanisms.

  • 26.
    Nascimento, Francisco J. A.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Svendsen, Claus
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Joint Toxicity of Cadmium and Ionizing Radiation on Zooplankton Carbon Incorporation, Growth and Mobility2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 3, p. 1527-1535Article in journal (Refereed)
    Abstract [en]

    The risk of exposure to radioactive elements is seldom assessed considering mixture toxicity, potentially over-or underestimating biological and ecological effects on ecosystems. This study investigated'how three end points, carbon transfer between phytoplankton and Daphnia magna, D. magna mobility and growth, responded to exposure to gamma-radiation in combination with the heavy metal cadmium (Cd), using the MIXTOX approach. Observed effects were compared with mixture effects predicted by concentration addition (CA) and independent action (IA) models and with deviations for synergistic/antagonistic (S/A), dose-level (DL), and dose-ratio (DR) dependency interactions. Several patterns of response were observed depending on the end point tested. DL-dependent deviation from the IA model was observed for carbon incorporation with antagonism switching to synergism at higher doses, while the CA model indicated synergism, mainly driven by effects at high doses of gamma-radiation. CA detected= antagonism regarding acute immobilization, while IA predicted DR dependency. Both CA and IA also identified antagonism for daphnid growth. In general, effects of combinations of gamma-radiation and Cd seem to be antagonistic at lower doses, but synergistic at the higher range of.the doses tested. Our results highlight the importance of investigating the effects of exposure to gamma-radiation in a multistressor context.

  • 27.
    Stark, Karolina
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gomez-Ros, José M.
    Bathe, Jordi Vives I.
    Lindbo Hansen, Elisabeth
    Beaugelin-Seiller, Karine
    Kapustka, Lawrence A.
    Wood, Michael D.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Real, Almudena
    McGuire, Corynne
    Hinton, Thomas G.
    Dose assessment in environmental radiological protection: State of the art and perspectives2017In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 175, p. 105-114Article, review/survey (Refereed)
    Abstract [en]

    Exposure to radiation is a potential hazard to humans and the environment. The Fukushima accident reminded the world of the importance of a reliable risk management system that incorporates the dose received from radiation exposures. The dose to humans from exposure to radiation can be quantified using a well-defined system; its environmental equivalent, however, is still in a developmental state. Additionally, the results of several papers published over the last decade have been criticized because of poor dosimetry. Therefore, a workshop on environmental dosimetry was organized by the STAR (Strategy for Allied Radioecology) Network of Excellence to review the state of the art in environmental dosimetry and prioritize areas of methodological and guidance development. Herein, we report the key findings from that international workshop, summarise parameters that affect the dose animals and plants receive when exposed to radiation, and identify further research needs. Current dosimetry practices for determining environmental protection are based on simple screening dose assessments using knowledge of fundamental radiation physics, source-target geometry relationships, the influence of organism shape and size, and knowledge of how radionuclide distributions in the body and in the soil profile alter dose. In screening model calculations that estimate whole-body dose to biota the shapes of organisms are simply represented as ellipsoids, while recently developed complex voxel phantom models allow organ specific dose estimates. We identified several research and guidance development priorities for dosimetry. For external exposures, the uncertainty in dose estimates due to spatially heterogeneous distributions of radionuclide contamination is currently being evaluated. Guidance is needed on the level of dosimetry that is required when screening benchmarks are exceeded and how to report exposure in dose-effect studies, including quantification of uncertainties. Further research is needed to establish whether and how dosimetry should account for differences in tissue physiology, organism life stages, seasonal variability (in ecology, physiology and radiation field), species life span, and the proportion of a population that is actually exposed. We contend that, although major advances have recently been made in environmental radiation protection, substantive improvements are required to reduce uncertainties and increase the reliability of environmental dosimetry.

  • 28.
    Tjensvoll, Ingrid
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Eklund, Britta
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Johansson, Lisen
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Suspension of TBT-contaminated sediment causes physiologicalstress in macroalgae and blue musselsManuscript (preprint) (Other academic)
    Abstract [en]

    Tributyltin is a toxic compound that has been used in antifouling paint for boats andships. Due to the immediate toxic effects at very low concentrations it was banned in many countries in 1986. Due to its slow degradation it is expected to be stored in the sediment for many decades. This experiment simulated a small boat harbour with frequent resuspension events of TBT-contaminated sediment to measure the impacts onthe release, bioavailability and effects of tributyltin. Physiological stress responses were measured in two coastal species, the blue mussel, Mytilus edulis, and the red algaCeramium tenuicorne. Response variables measured were respiration, ammonia excretion, clearance rate and survival rate (for mussels) and growth inhibition (for thealga). Resuspension released both dissolved and particle-bound TBT to the surrounding water and made it bioavailable for both organisms. There was a clear toxic effect of the highest concentrations and it was evident that both mussels and algae showed a fasterand more negative response when the sediment was suspended. Repeated or continuous exposure to suspended TBT-contaminated sediment can exert a risk to the organisms living in environments such as harbours.

  • 29.
    Tjensvoll, Ingrid
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sköld, Mattias
    Swedish University of Agricultural Sciences (SLU), Department of Aquatic Resources, Institute of Marine Research.
    Jönsson, Anette
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The extent of sediment resuspension caused by bottom trawling, storms, and dredging in the Baltic ProperManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    This study compares the extent and frequency of seafloor disturbances due to anthropogenic processes (bottom trawling and dredging) with those due to wind-driven waves in the Baltic Proper. There is little overlap between areas affected by bottom trawlers and naturally from waves, and bottom trawling is the main cause of sediment resuspension at greater (>73m) depths. Swedish bottom trawlers annually suspend between 3.8 and 13.6 M tonnes in this area, while from the reported dredging projects (reported between 2007 and 2009) the estimated maximum annual spillage was 0.14 M tonnes. The dominance of bottom trawling as a factor suspending sediment is clear, but management approaches for bottom trawling and dredging are different, despite similar expected effects on organisms and the environment. 

  • 30. Vanhoudt, Nathalie
    et al.
    Vandenhove, Hildegarde
    Real, Almudena
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Stark, Karolina
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    A review of multiple stressor studies that include ionising radiation2012In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 168, p. 177-192Article, review/survey (Refereed)
    Abstract [en]

    Studies were reviewed that investigated the combined effects of ionising radiation and other stressors on non-human biota. The aim was to determine the state of research in this area of science, and determine if a review of the literature might permit a gross generalization as to whether the combined effects of multi-stressors and radiation are fundamentally additive, synergistic or antagonistic. A multiple stressor database was established for different organism groups. Information was collected on species, stressors applied and effects evaluated. Studies were mostly laboratory based and investigated two-component mixtures. Interactions declared positive occurred in 58% of the studies, while 26% found negative interactions. Interactions were dependent on dose/concentration, on organism's life stage and exposure time and differed among endpoints. Except for one study, none of the studies predicted combined effects following Concentration Addition or Independent Action, and hence, no justified conclusions can be made about synergism or antagonism.

  • 31. Vives i Batlle, J.
    et al.
    Aoyama, M.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Brown, J.
    Buesseler, K. O.
    Casacuberta, N.
    Christl, M.
    Duffa, C.
    Impens, N. R. E. N.
    Iosjpe, M.
    Masque, P.
    Nishikawa, J.
    Marine radioecology after the Fukushima Dai-ichi nuclear accident: Are we better positioned to understand the impact of radionuclides in marine ecosystems?2018In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 618, p. 80-92Article in journal (Refereed)
    Abstract [en]

    This paper focuses on how a community of researchers under the COMET (CO-ordination and iMplementation of a pan European projecT for radioecology) project has improved the capacity of marine radioecology to understand at the process level the behaviour of radionuclides in the marine environment, uptake by organisms and the resulting doses after the Fukushima Dai-ichi nuclear accident occurred in 2011. We present new radioecological understanding of the processes involved, such as the interaction of waterborne radionuclides with suspended particles and sediments or the biological uptake and turnover of radionuclides, which have been better quantified and mathematically described. We demonstrate that biokinetic models can better represent radionuclide transfer to biota in non-equilibrium situations, bringing more realism to predictions, especially when combining physical, chemical and biological interactions that occur in such an open and dynamic environment as the ocean. As a result, we are readier now than we were before the FDNPP accident in terms of having models that can be applied to dynamic situations. The paper concludes with our vision for marine radioecology as a fundamental research discipline and we present a strategy for our discipline at the European and international levels. The lessons learned are presented along with their possible applicability to assess/reduce the environmental consequences of future accidents to the marine environment and guidance for future research, as well as to assure the sustainability of marine radioecology. This guidance necessarily reflects on why and where further research funding is needed, signalling the way for future investigations.

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