Bioavailability Of Organic Chemicals In Soil And Sediment

This book discusses bioavailability concepts and methods, summarizing the current knowledge on bioavailability science, as well as possible pathways for integrating bioavailability into risk assessment and the regulation of organic chemicals. Divided into 5 parts, it begins with an overview of chemical distribution in soil and sediment, as well as the bioavailability and bioaccumulation of chemicals in plants, soil, invertebrates and vertebrates (including humans). It then focuses on the impact of sorption processes and reviews bioavailability measurement methods. The closing chapters discuss the impact of bioavailability studies on chemical risk assessment, and highlights further research needs. Written by a multi-disciplinary team of authors, it is an essential resource for scientists in academia and industry, students, as well as for authorities.

Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.

In the continuing fight against organic environmental xenobiotics, the initial success attributed to bioremediation has paled, in part due to the low availability of xenobiotics entrapped within a soil or sediment matrix. This has generated a very significant wave of interest in the bioavailability issue. However, much experimental evidence is puzzling or contradictory, mechanistic theories are embryonic, and implications for the practice of bioremediation or concerning the natural fate of xenobiotics are still tentative. The debate in Europe and the USA is vigorous. Eastern Europe, following the liberalisation of the economy and political life, is evolving in a similar direction. In many cases, however, limited access to literature sources, severe language barriers, and the lack of a strong pluridisciplinary tradition are hampering the adoption of state of the art techniques. Originally intended to allow scientists in East European countries to become acquainted with the key aspects of the bioavailability debate that is unfolding in the scientific literature in the West, and with its implications for bioremediation efforts, the present book presents a very complete coverage of the theoretical and practical aspects of the (limited) bioavailability of organic xenobiotics in the environment.

Soil and Sediment Remediation discusses in detail a whole set of remediative technologies currently available to minimise their impact. Technologies for the treatment of soils and sediments in-situ (landfarming, bioscreens, bioventing, nutrient injection, phytoremediation) and ex-situ (landfarming, bio-heap treatment, soil suspension reactor) will be discussed. The microbiological, process technological and socio-economical aspects of these technologies will be addressed. Special attention will be given to novel biotechnological processes that utilise sulfur cycle conversions, e.g. sulfur and heavy metal removal from soils. Also the potential of phytoremediation will be highlighted. In addition, treatment schemes for the clean-up of polluted megasites, e.g. harbours and Manufactured Gaswork Plants (MGP), will be elaborated. The aim of Soil and Sediment Remediation is to introduce the reader in: the biogeochemical characteristics of soil and sediments- new techniques to study soil/sediment processes (molecular probes, microelectrodes, NMR) clean up technologies for soils polluted with organic (PAH, NAPL, solvents) or inorganic (heavy metals) pollutants- preventative and remediative strategies and technologies available in environmental engineering novel process applications and bioreactor designs for bioremediation the impact of soil pollution on society and its economic importance.

This book begins with an overview of current thinking on bioavailability, its definition, cutting-edge research in speciation and advancement in tools for assessing chemical bioavailability in the terrestrial environment. The second section of the book focuses on the role of chemical speciation in bioavailability. Section three addresses bioavailability and ecotoxicity of contaminants and leads into the next section on bioavailability of nutrients and agrichemicals. Subsequent sections provide an overview of tools currently being used and new cutting-edge techniques to assess contaminant bioavailability. The last section of the book builds on previous sections in relating bioavailability to risk assessment and how this could be used for managing risks associated with contaminated land. Provides the latest information on developing concepts and definitions of bioavailability Includes a discussion of bioavailability and ecotoxicity of contaminants and bioavailability of nutrients and agrichemicals for applications in agriculture Analyzes tools for assessing bioavailability and the role of bioavailability in risk assessment and remediation

Theoretical considerations of the partition uptake of nonionic organic compounds by soil organic matter. The sorption of nonpolar organics by soils and sediments. Sorption dynamics of organic compounds in soils and sediments. Adsorption and reactions of selected organic molecules on clay mineral surfaces. Effect of sunlight on organic contaminants at the atmosphere-soil interface. Dehalogenation of pesticides by anaerobic microorganisms in soils and groundwater: a review. Volatilization of pesticides from soil. Chlorophenols in soils. Hydrolytic transformations of organic chemicals in the environment. Kinetics of biodegradation in soil. Overview of organic chemical environmental fate and transport modeling approaches. Organic chemical movement over and through soil. Environmental behavior of aquatic herbicides in sediments. Transport processes involving organic chemicals. Movement of volatile organic chemicals in soils. Nonequilibrium transport of organic contaminants in groundwater. Hydrologic processes affecting the movement of organic chemicals in soils. Movement of organic chemicals through landfills and hazardous waste disposal sites.

The increasing awareness of the effects of pollutants in the eco-system and on the development of suitable methods of analysis has stimulated a lot of research recently. This volume comprehensively discusses the range of methods available for the analysis and determination of organic compounds in soils, river and marine sediments and industrial sludges. A review is provided of the instrumentation used in soil and sediment laboratories and an indication of the types of organics that can be determined by each technique. Subsequent chapters discuss the analysis of various types of organics in a logical and systematic manner. Guidance is provided on the applicability of techniques in certain environments, the advantages and disadvantages of using one method over another, likely interference, the sensitivity of particular techniques, and detection limits. The work will be of interest to agricultural chemists, agriculturists concerned with ways in which organic chemicals used in crop or soil treatment permeate the ecosystem and to biologists and scientists involved in fish, plant and insect life. Toxicologists, public health workers, oceanographers, and environmentalists will also find the book beneficial.

In contrast to the classical books which largely focus on separate, individual physicochemical and biological aspects, this book aims to integrate the frontiers of knowledge on the fundamentals and the impact of physicochemical and biological interactions and processes of AOCs in soil, sediment, water and air. The specific objectives of this book are to address: (1) fundamental biophysico-chemical processes of AOCs in the environment, (2) occurrence and distribution of AOCs in air, water, and soil, and their global cycling, (3) the state-of-the-art analytical techniques of AOCs, and (4) restoration of natural environments contaminated by AOCs. The book also identifies the gaps in knowledge on the subject matter and as such provides future directions to stimulate scientific research to advance the chemical science on biophysico-chemical interfacial reactions in natural habitats. By virtue of complex nature of the interactions of AOCs with different environmental components and matrixes, no single available technique and instrument is satisfactory yet for determining their fate, transport, availability, and risk in the environment. In order to fully understand the biophysico-chemical interactions and processes of AOCs in the environment, it is critical to know chemical, physical and biological properties of AOCs and their analytical techniques. The book is unique because of its multidisciplinary approach as it provides a comprehensive and integrated coverage of biophysico-chemical reactions and processes of AOCs in various environments, associated analytical techniques, and restoration of natural environments contaminated by AOCs.