SRC willow development, biomass composition and biofuel potential

The aims of this PhD were to examine nitrogen allocation and partitioning in Short Rotation Coppice (SRC) willow in regard to tree development and to investigate biomass composition and cell wall structure for the purpose of assessing and understanding biofuel potential. To address these topics four major experiments were performed and are presented in the thesis. An investigation of SRC willow development and nitrogen dynamics was conducted as a pot trial comprising 14 different genotypes from a willow mapping population. The genotypes were selected on the extremity and consistency of their field biomass yields. Fertiliser enriched with the stable isotope nitrogen 15 was applied as a means of nitrogen surveillance. One of the findings was that higher biomass yielding varieties of SRC willow had increased nitrogen-use-efficiency yet less (or later) nitrogen remobilisation in the autumn. The recalcitrance of the cell wall to enzymatic saccharification was assessed across 138 field-grown genotypes of the same willow mapping population. The aim was to identify any relationships between glucose yield and several biomass yield traits and to identify any quantitative trait loci (QTL) associated with enzymatic saccharification. Four QTL associated to enzymatic saccharification were identified and no relationship was found between glucose and biomass yield traits. A third experiment aimed to modify cell wall composition and structure of a single cultivar of willow grown in a pot trial. Tension wood, fibre cells containing an extra cell wall layer unique to angiosperms, and cellulose synthesis inhibited phenotypes were both induced. These modifications were accomplished through chemical and environmental treatments during development and their impact on composition and cell wall recalcitrance was assessed. Tension wood formation was found to increase glucose yields. The final main experiment used 35 of the UK’s leading biomass yielding willow varieties, grown in the field, to assess not only the variation in composition and enzymatic saccharification but also to identify any relationships between these two traits and a variety of morphological traits. The final part of the experiment investigated how variation in these traits interacted with dilute acid pretreatment. Surprisingly lignin content did not significantly correlate with cell wall recalcitrance to enzymatic saccharification. Another important finding was that enzymatic saccharification without the pretreatment correlated with enzymatic saccharification after the pretreatment. General introduction and general materials and methods chapters are included. A final summary discussion chapter is also included in order to address the overall impact of these findings on biofuel potential

Webportal

Establish (and maintain) an innovative webportal (the Radioecology Exchange). Ahead of schedule an interim open access website (wiki) was created in time for the STAR project to be publicised at the International Conference on Radioecology and Environmental Radioactivity held in Hamilton, Canada in June 2011. Prior to this a protected access website (also a wiki) was created for STAR partners to exchange information. The open access website was upgraded in October 2011 and is continually developing as the project progresses

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

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

Should we ignore U-235 series contribution to dose?

Environmental Risk Assessment (ERA) methodology for radioactive substances is an important regulatory tool for assessing the safety of licensed nuclear facilities for wildlife, and the environment as a whole. ERAs are therefore expected to be both fit for purpose and conservative. When uranium isotopes are assessed, there are many radioactive decay products which could be considered. However, risk assessors usually assume 235U and its daughters contribute negligibly to radiological dose. The validity of this assumption has not been tested: what might the 235U family contribution be and how does the estimate depend on the assumptions applied? In this paper we address this question by considering aquatic wildlife in Canadian lakes exposed to historic uranium mining practices. A full theoretical approach was used, in parallel to a more realistic assessment based on measurements of several elements of the U decay chains. The 235U family contribution varied between about 4% and 75% of the total dose rate depending on the assumptions of the equilibrium state of the decay chains. Hence, ignoring the 235U series will not result in conservative dose assessments for wildlife. These arguments provide a strong case for more in situ measurements of the important members of the 235U chain and for its consideration in dose assessments

Education and training in radioecology during the EU-COMET project-successes and suggestions for the future

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 ... 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

Whole-organism concentration ratios in wildlife inhabiting Australian uranium mining environments

Wildlife concentration ratios for 226Ra, 210Pb, 210Po and isotopes of Th and U from soil, water, and sediments were evaluated for a range of Australian uranium mining environments. Whole-organism concentration ratios (CRwo-media) were developed for 271 radionuclide-organism pairs within the terrestrial and freshwater wildlife groups. Australian wildlife often has distinct physiological attributes, such as the lower metabolic rates of macropod marsupials as compared with placental mammals. In addition, the Australian CRswo-media originate from tropical and semi-arid climates, rather than from the temperate-dominated climates of Europe and North America from which most (>90%) of internationally available CRwo-media values originate. When compared, the Australian and non-Australian CRs are significantly different for some wildlife categories (e.g. grasses, mammals) but not others (e.g. shrubs). Where differences exist, the Australian values were higher, suggesting that site-, or region-specific CRswo-media should be used in detailed Australian assessments. However, in screening studies, use of the international mean values in the Wildlife Transfer Database (WTD) appears to be appropriate, as long as the values used encompass the Australian 95th percentile values. Gaps in the Australian datasets include a lack of marine parameters, and no CR data are available for freshwater phytoplankton, zooplankton, insects, insect larvae or amphibians; for terrestrial environments, there are no data for amphibians, annelids, ferns, fungi or lichens & bryophytes. The new Australian specific parameters will aide in evaluating remediation plans and ongoing operations at mining and waste sites within Australia. They have also substantially bolstered the body of U- and Th-series CRwo-media data for use internationally