Organic chemical exposure in soil toxicity tests and in ecological risk assessment of terrestrial systems is usually expressed as the total chemical measured. Possible alternatives to total chemical measures of organic chemical bioavailability and exposure include body residues in test organisms, soil extraction with selective solvents, and passive sampling devices (PSDs) as biological surrogates. Semipermeable membrane devices (SPMDs) offer potential as a biological surrogate in soil systems. Solid-phase microextraction (SPME) fibers are a rapid and sensitive means for detecting PAHs in soil and have the advantage of not requiring solvent extraction of soil. The objective of this study was to compare chemical uptake and residues in earthworms, SPMDs, and SPMEs exposed in artificial soil spiked with phenanthrene (PHE). Bioavailable PHE, as assessed by mortality and PHE body residues, varied dramatically with soil organic matter content. Both SPMEs and SPMDs could discriminate differences in PHE availability between treatments. However, PHE levels measured using SPMEs were more precise and allowed discrimination between toxic and non-toxic levels of PHE, while PHE levels in SPMDs were too variable for use as a predictive tool.

In this book, both basic and advanced concepts are discussed for considering mixtures from initial exposure characterization through evaluation of risk associated with combined exposures. This book will provide an introduction to key issues and multiple options for evaluating both the toxicity of mixtures as well as the risk associated with exposure to mixtures. Additionally, promising tools adapted from other disciplines will be discussed in the context of mixtures toxicology and risk assessment. Finally, the discussion will move beyond chemical mixtures to address incorporating non-chemical stressors into toxicity studies and cumulative risk assessments. Although exposure to multiple chemical and non-chemical stressors is the rule, not the exception, consideration of mixtures in toxicology and risk assessment continues to be a significant challenge. This book will be an essential resource for researchers and professionals in the fields of toxicology, epidemiology, exposure science, risk assessment, and statistics.

Some of the nation's estuaries, lakes and other water bodies contain contaminated sediments that can adversely affect fish and wildlife and may then find their way into people's diets. Dredging is one of the few options available for attempting to clean up contaminated sediments, but it can uncover and re-suspend buried contaminants, creating additional exposures for wildlife and people. At the request of Congress, EPA asked the National Research Council (NRC) to evaluate dredging as a cleanup technique. The book finds that, based on a review of available evidence, dredging's ability to decrease environmental and health risks is still an open question. Analysis of pre-dredging and post-dredging at about 20 sites found a wide range of outcomes in terms of surface sediment concentrations of contaminants: some sites showed increases, some no change, and some decreases in concentrations. Evaluating the potential long-term benefits of dredging will require that the U.S. Environmental Protection Agency step up monitoring activities before, during and after individual cleanups to determine whether it is working there and what combinations of techniques are most effective.

Following up on his popular Techniques in Aquatic Toxicology with a second volume, now nine years later, Dr. Ostrander has once again called on the top aquatic toxicologists from across the world to present 39 chapters of unique collection and testing procedures. Updating five techniques from the first volume, the authors have gone on to add over two dozen new techniques. Every chapter covers a specific procedure that can easily be reproduced by any competent technician with basic knowledge. Each of the chapter authors provides and interprets typical and anomalous results, false positives, and artifacts. Data is provided either from recently published experiments or from work being published for the first time.