Radionuclide Contamination And Remediation Through Plants

This book focuses on the mechanistic (microscopic) understanding of radionuclide uptake by plants in contaminated soils and potential use of phytoremediation. The key features concern radionuclide toxicity in plants, how the radioactive materials are absorbed by plants, and how the plants cope with the toxic responses. The respective chapters examine soil classification, natural plant selection, speciation of actinides, kinetic modeling, and case studies on cesium uptake after radiation accidents. Radionuclide contaminants pose serious problems for biological systems, due to their chemical toxicity and radiological effects. The processes by which radionuclides can be incorporated into vegetation can either originate from activity interception by external plant surfaces (either directly from the atmosphere or from resuspended material), or through uptake of radionuclides via the root system. Subsequent transfer of toxic elements to the human food chain is a concrete danger. Therefore, the molecular mechanisms and genetic basis of transport into and within plants needs to be understood for two reasons: The effectiveness of radionuclide uptake into crop plants – so-called transfer coefficient – is a prerequisite for the calculation of dose due to the food path. On the other hand, efficient radionuclide transfer into plants can be made use of for decontamination of land – so-called phytoremediation, the direct use of living, green plants for in situ removal of pollutants from the environment or to reduce their concentrations to harmless levels.

This book provides extensive and comprehensive information to researchers and academicians who are interested in radionuclide contamination, its sources and environmental impact. It is also useful for graduate and undergraduate students specializing in radioactive-waste disposal and its impact on natural as well as manmade environments. A number of sites are affected by large legacies of waste from the mining and processing of radioactive minerals. Over recent decades, several hundred radioactive isotopes (radioisotopes) of natural elements have been produced artificially, including 90Sr, 137Cs and 131I. Several other anthropogenic radioactive elements have also been produced in large quantities, for example technetium, neptunium, plutonium and americium, although plutonium does occur naturally in trace amounts in uranium ores. The deposition of radionuclides on vegetation and soil, as well as the uptake from polluted aquifers (root uptake or irrigation) are the initial point for their transfer into the terrestrial environment and into food chains. There are two principal deposition processes for the removal of pollutants from the atmosphere: dry deposition is the direct transfer through absorption of gases and particles by natural surfaces, such as vegetation, whereas showery or wet deposition is the transport of a substance from the atmosphere to the ground by snow, hail or rain. Once deposited on any vegetation, radionuclides are removed from plants by the airstre am and rain, either through percolation or by cuticular scratch. The increase in biomass during plant growth does not cause a loss of activity, but it does lead to a decrease in activity concentration due to effective dilution. There is also systemic transport (translocation) of radionuclides within the plant subsequent to foliar uptake, leading the transfer of chemical components to other parts of the plant that have not been contaminated directly.

This book provides extensive and comprehensive information to researchers and academicians who are interested in radionuclide contamination, its sources and environmental impact. It is also useful for graduate and undergraduate students specializing in radioactive-waste disposal and its impact on natural as well as manmade environments. A number of sites are affected by large legacies of waste from the mining and processing of radioactive minerals. Over recent decades, several hundred radioactive isotopes (radioisotopes) of natural elements have been produced artificially, including 90Sr, 137Cs and 131I. Several other anthropogenic radioactive elements have also been produced in large quantities, for example technetium, neptunium, plutonium and americium, although plutonium does occur naturally in trace amounts in uranium ores. The deposition of radionuclides on vegetation and soil, as well as the uptake from polluted aquifers (root uptake or irrigation) are the initial point for their transfer into the terrestrial environment and into food chains. There are two principal deposition processes for the removal of pollutants from the atmosphere: dry deposition is the direct transfer through absorption of gases and particles by natural surfaces, such as vegetation, whereas showery or wet deposition is the transport of a substance from the atmosphere to the ground by snow, hail or rain. Once deposited on any vegetation, radionuclide s ar e removed from plants by the airstream and rain, either through percolation or by cuticular scratch. The increase in biomass during plant growth does not cause a loss of activity, but it does lead to a decrease in activity concentration due to effective dilution. There is also systemic transport (translocation) of radionuclides within the plant subsequent to foliar uptake, leading the transfer of chemical components to other parts of the plant that have not been contaminated directly.

In recent years, radioactive contamination in the environment by uranium (U) and its daughters has caused increasing concerns globally. This book provides recent developments and comprehensive knowledge to the researchers and academicians who are working on uranium contaminated areas worldwide. This book covers topics ranging from the beginning of the nuclear age until today, including historical views and epidemiological studies. Modelling practices and evaluation of radiological and chemical impact of uranium on man and the environment are included. Also covered are analytical methods used for the determination of uranium in geo/bio environments. Some chapters explore factors which influence uranium speciation and in consequence plant uptake/translocation. Last but not least, several chapters provide approaches and practices for remediation of uranium contaminated areas.

Most of the nuclear facilities built since the Second World War have ceased active operation and have been decommissioned. Some of the sites are heavily contaminated with radioactive substances. Correct and efficient action to mitigate the radiological consequences of such contamination will only be possible when the behaviour of radionuclides in the terrestrial environment is sufficiently well known. Yet radioecologists often find it difficult to study the transfer of radioactivity in agricultural land and semi-natural ecosystems, because of the complexity and diversity of such environments. The present book presents an analysis of all the factors that affect the behaviour of radionuclides as they move from their point of release through the environment and then enter the tissues of biota living in the ecosystems, in particular plants and animals consumed by humans. The course on which the book is based was held in a region that is heavily contaminated by radioactive discharges into the environment during nuclear weapons fabrication in the 1950s and '60s, and due to a severe accidental release following the explosion of a rad-waste tank in 1957. This allowed in situ training of the students. The book's main emphasis is on specific radioecological problems in severely contaminated areas in the former Soviet Union: the Southern Urals Trail, the rivers Techa-Isert-Tobol-Irtis-Ob, and the 30 km zone around Chernobyl. Systems examined include soils, arable and pasture land, forests, lakes and rivers. Special attention is paid to the effects of radiation on natural ecosystems: trees, soil-dwelling organisms, and aquatic organisms. Synergistic effects are also considered. Short, medium and long term countermeasures are discussed.

This book offers extensive and comprehensive knowledge to the researchers and academicians who are working on decontamination of radioactively contaminated areas. Remediation strategies for contaminated sites are provided. Readers who will find this book useful include professionals specializing in radioecology, safe disposal of radioactive waste, as well as decontamination, remediation legacies and impact of radioactive waste material on the environment. The chapters give a broad overview and reviews of a number of original publications on remediation strategies that were explored after the Chernobyl and Fukushima Nuclear Power plant accidents. Useful case studies are provided that explore the latest technological developments and future trends for affected area decontamination.

Inorganic Contaminants and Radionuclides is a single reference covering common inorganic contaminants in detail, including their distribution in the environment, challenges linked to management, geogenic sources, anthropogenic sources, exposure and effects, international agreements and legislation relating to the contaminant, remediation options and global case studies. In addition, the book provides summaries of contaminated sites and key details about contaminants to present a more comprehensive understanding and improve remediation and management practices. The book's clear, consistent organization makes it a valuable resource for researchers, students and practitioners working in environmental science, environmental management and environmental engineering. One of the major constraints to assessing and remediating contaminated sites is the lack of awareness of the extent and severity of contaminated sites amongst the community, regulators, policymakers, industry operators, university graduates and environmental managers. This book helps to manage these constraints. Provides a one-stop reference on the nature and properties of inorganic contaminants, including a transdisciplinary approach to managing contaminated sites Includes global case studies covering contaminated site assessment, management and remediation Presents in-depth research and data on specific contaminants, with a separate chapter for each contaminant

Behaviour and significance of radioactive substances released into agricultural, forestry and fisheries; Radioation in the environment; Radioecology, behaviour, significance, models; Chernobyl and other accidents; Some international situation in Europe after Chernobyl; Some international implications; Soil and crop contamination by rarioactive fallout; Agricultural and forestry soils as a vital global resource; Soil in the nutrient cycle; Sources and nature of radioactive contamination; Biological significance of contaminated soils; Behaviour in soils and movement into foodwebs; Detection and measurement; Countermeasures, reclamation and use of contaminated soils; Concluding comments; some questions and needs.