Temporal changes in gamma dose rates in the Esk Estuary, UK

Over the last 30 years there has been a reduction in the radioactive discharges from the UK's Sellafield site. Radionuclide activity concentrations in the environment around Sellafield have declined as a result. However, routine monitoring results from the nearby Esk Estuary show a less clear trend, with fluctuations in gamma dose rate measurements being reported from year to year. A comprehensive survey (n = 576) of gamma dose rates in the Esk Estuary was undertaken in 2007 and the data compared to a similar survey carried out in 1989. There was a highly statistically significant decrease in the external gamma dose rates within the Esk Estuary between 1989 and 2007. The measured total gamma dose rate range in 2007 was 0.064 - 0.235 μGy h-1with a mean of 0.123 μGy h-1. This equates to a maximum exposure of 0.200 μSv h-1. There was no evidence of large-scale sediment redistribution under current conditions. However, there was limited evidence to suggest that part of the reason for the reduction in measured dose rates was the burial of contaminated sediment deposits by uncontaminated sediments transported by tidal processes

Cadmium uptake from sediment by Cylindrotheca closterium and the effect of diatom presence on partitioning of cadmium between sediment and water: A laboratory study

Although it is well established that microalgae take up metals and other contaminants from water and it has been suggested that algae may play a significant role in mobilizing sediment bound contaminants, there has been little research on the uptake of sediment‐associated contaminants by microalgae. This may be important for microphytobenthos, which is closely associated with sediments. We report on laboratory experiments investigating the uptake of cadmium (Cd) from sediment and water by Cylindrotheca closterium over 96 h. The role of microalgae in the partitioning of Cd between sediment and water was also investigated. While concentrations do not typically represent those in the natural environment, we showed C. closterium takes up Cd from sediment, and concentration in microalgae is affected by sediment organic matter content. Cylindrotheca closterium influenced Cd movement between sediment and water: transfer from water to sediment was slowed, while transfer from sediment to overlying water (all treatments) and interstitial water (unprocessed sediment treatments) was increased. This is the first article to describe Cd uptake by diatoms from intertidal sediment in relation to sediment properties and mobilization of Cd from sediment in the presence of diatoms. Microalgae may serve as a pathway for sediment‐associated metals to enter into aquatic food webs, and their presence appears to increase metal concentrations in water potentially making any mobilized metals available for uptake by other species. Given this and their importance as the basis of the food chain, there may be implications for environmental and human health and potential impacts for the biological stability of the sediment

Uptake and partitioning of metals by microphytobenthic diatoms: metadata for the ARCoES project

As part of University of Stirling's contribution to the ARCoES project, data were collected to determine the uptake and mobilisation of metals associated with estuarine intertidal sediment by microphytobenthic diatoms. The research was carried out as three studies at a range of scales and levels of realism, from a laboratory experiment in a controlled environment facility, through a study using an intertidal mesocosm, to the field. http://hdl.handle.net/11667/11

Radiological Protection of the Environment

Ecotoxicology offers a comprehensive overview of the science underpinning the recognition and management of environmental contamination. It describes the toxicology of environmental contaminants, the methods used for assessing their toxicity and ecological impacts, and approaches employed to mitigate pollution and ecological health risks globally. Chapters cover the latest advances in research, including genomics, natural toxins, endocrine disruption and the toxicology of radioactive substances. The second half of the book focuses on applications, such as cradle-to-grave effects of selected industries, legal and economic approaches to environmental regulation, ecological risk assessment, and contaminated site remediation. With short capsules written by invited experts, numerous case studies from around the world and further reading lists, this textbook is designed for advanced undergraduate and graduate one-semester courses. It is also a valuable reference for graduate students and professionals. Online resources for instructors and students are also available

A method for assessing exposure of terrestrial wildlife to environmental radon ( 222 Rn) and thoron ( 220 Rn)

A method is presented to calculate radiation dose rates arising from radon, thoron and their progeny to non-human biota in the terrestrial environment. The method improves on existing methodologies for the assessment of radon to biota by using a generalised allometric approach to model respiration, calculating dose coefficients for the ICRP reference animals and plants, and extending the approach to cover thoron in addition to radon-derived isotopes. The method is applicable to a range of environmental situations involving these radionuclides in wildlife, with an envisaged application being to study the impact of human activities, which bring NORM radionuclides to the biosphere. Consequently, there is a need to determine whether there is an impact on non-human biota from exposure to anthropogenically enhanced radionuclides

Radiological Protection of the Environment

Ecotoxicology offers a comprehensive overview of the science underpinning the recognition and management of environmental contamination. It describes the toxicology of environmental contaminants, the methods used for assessing their toxicity and ecological impacts, and approaches employed to mitigate pollution and ecological health risks globally. Chapters cover the latest advances in research, including genomics, natural toxins, endocrine disruption and the toxicology of radioactive substances. The second half of the book focuses on applications, such as cradle-to-grave effects of selected industries, legal and economic approaches to environmental regulation, ecological risk assessment, and contaminated site remediation. With short capsules written by invited experts, numerous case studies from around the world and further reading lists, this textbook is designed for advanced undergraduate and graduate one-semester courses. It is also a valuable reference for graduate students and professionals. Online resources for instructors and students are also available

Low dose γ-radiation induced effects on wax moth (Galleria mellonella) larvae

Larvae of the greater wax moth Galleria mellonella are common pests of beehives and commercial apiaries, and in more applied settings, these insects act as alternative in vivo bioassays to rodents for studying microbial virulence, antibiotic development, and toxicology. In the current study, our aim was to assess the putative adverse effects of background gamma radiation levels on G. mellonella. To achieve this, we exposed larvae to low (0.014 mGy/h), medium (0.056 mGy/h), and high (1.33 mGy/h) doses of caesium-137 and measured larval pupation events, weight, faecal discharge, susceptibility to bacterial and fungal challenges, immune cell counts, activity, and viability (i.e., haemocyte encapsulation) and melanisation levels. The effects of low and medium levels of radiation were distinguishable from the highest dose rates used – the latter insects weighed the least and pupated earlier. In general, radiation exposure modulated cellular and humoral immunity over time, with larvae showing heightened encapsulation/melanisation levels at the higher dose rates but were more susceptible to bacterial (Photorhabdus luminescens) infection. There were few signs of radiation impacts after 7 days exposure, whereas marked changes were recorded between 14 and 28 days. Our data suggest that G. mellonella demonstrates plasticity at the whole organism and cellular levels when irradiated and offers insight into how such animals may cope in radiologically contaminated environments (e.g. Chornobyl Exclusion Zone)

Variation in chronic radiation exposure does not drive life history divergence among Daphnia populations across the Chernobyl Exclusion Zone

Ionizing radiation is a mutagen with known negative impacts on individual fitness. However, much less is known about how these individual fitness effects translate into population‐level variation in natural environments that have experienced varying levels of radiation exposure. In this study, we sampled genotypes of the freshwater crustacean, Daphnia pulex, from the eight inhabited lakes across the Chernobyl Exclusion Zone (CEZ). Each lake has experienced very different levels of chronic radiation exposure since a nuclear power reactor exploded there over thirty years ago. The sampled Daphnia genotypes represent genetic snapshots of current populations and allowed us to examine fitness‐related traits under controlled laboratory conditions at UK background dose rates. We found that whilst there was variation in survival and schedules of reproduction among populations, there was no compelling evidence that this was driven by variation in exposure to radiation. Previous studies have shown that controlled exposure to radiation at dose rates included in the range measured in the current study reduce survival, or fecundity, or both. One limitation of this study is the lack of available sites at high dose rates, and future work could test life history variation in various organisms at other high radiation areas. Our results are nevertheless consistent with the idea that other ecological factors, for example competition, predation or parasitism, are likely to play a much bigger role in driving variation among populations than exposure to the high radiation dose rates found in the CEZ. These findings clearly demonstrate that it is important to examine the potential negative effects of radiation across wild populations that are subject to many and varied selection pressures as a result of complex ecological interactions