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.

Although valuable resources in river basins and other aqueous environments, sediments often receive much less attention from researchers, policymakers, and other professionals than other components of the ecosystem. Until now. Highlighting the important role that sediments play in the geoenvironment, Sediments Contamination and Sustainable Remediat

Sediments are increasingly recognized as both a carrier and a possible source of contaminants in aquatic systems, and they may also affect groundwater quality and agricultural products when disposed on land. Four aspects are covered reflecting the development of knowledge in particle-associated pollutants during the past twenty-five years: - the identification, surveillance, monitoring and control of sources and distribution of pollutants, - the evaluation of solid/solution relations of contaminants in surface waters, - the study of in-situ processes and mechanisms of pollutant transfer in various compartments of the aquatic ecosystems, - the assessment of the environmental impact of particle-bound contaminants, i.e. the development of sediment quality criteria. A final chapter focusses on practical aspects concerning contaminated sediments.

This document is a compendium of scientifically valid and accepted methods that can be used to assess sediment quality and predict ecological impacts...the intent here is to provide the most useful overall measures or predictors of ecological impacts currently in use rather than procedures that may have limited application outside of a particular regulatory framework... parag The information provided in the compendium on the relative strengths and weaknesses of the different assessment methods can provide assistance in selecting the appropriate methods.

This book provides a risk-based framework for developing and implementing strategies to manage PCB-contaminated sediments at sites around the country. The framework has seven stages, beginning with problem definition, continuing through assessment of risks and management options, and ending with an evaluation of the success of the management strategy. At the center of the framework is continuous and active involvement of all affected parties-particularly communities-in the development, implementation, and evaluation of the management strategy. A Risk-Management Strategy for PCB-Contaminated Sediments emphasizes the need to consider all risks at a contaminated site, not just human health and ecological effects, but also the social, cultural, and economic impacts. Given the controversy that has arisen at many PCB-contaminated sites, this book provides a consistent, yet flexible, approach for dealing with the many issues associated with assessing and managing the risks at Superfund and other contaminated sites.