Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 39 (thesis year 1994) a total of 13,953 thesis titles from 21 Canadian and 159 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 39 reports theses submitted in 1994, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

Polychlorinated Biphenyls (PCBs) are synthetic chlorinated hydrocarbon compounds, produced commercially since 1929 for use in a variety of products including plastics and adhesives, surface coatings, inks, flame retardants, pesticides and paints. PCBs are environmentally persistent, and accumulate in the food chain. They are designated by the Stockholm Convention on Persistent Organic Pollutants as persistent pollutants, and many countries have severely restricted or banned the production of PCBs. This report evaluates the effects of PCBs on human health, caused due to exposure by inhaling contaminated air or ingesting contaminated food and water.

As progress towards a greater knowledge in sustainability science continues, the question of how better to integrate scientific progress with actual decisions made by practitioners remains paramount. This book aims to help close the gap between science and practice. Based on a two year collaborative project between Harvard and Clark Universities, the book takes as its focus the vulnerability and resilience of people around the world to the effects of environmental change, a mature area of research in which one might expect the gap between science and policy/practice to have been extensively bridged. The book presents analysis of past studies, interviews conducted with the producers and users of scientific knowledge, and case studies performed by leading scholars across a spectrum of international settings and political systems. Crucially, the authors identify new directions and tools for closing the gap between science and policy across a range of situations and societies. The result is an illuminating collection of studies and analyses that suggest to researchers, students, practitioners, and policy-makers alike how best to ensure that high quality environmental research informs good environmental policy and practice. ACKNOWLEDGEMENTS The editors and authors are grateful to Lu Ann Pacenka, who formatted the text of the book. The editors also wish to express their appreciation to Bill Clark and Nancy Dickson of Harvard University, who commissioned and provided oversight for the preparation of the volume. Both editors and authors wish to express their appreciation to the David and Lucile Packard Foundation for providing funds to support the project. Finally, the editors are grateful for the continuing support of the George Perkins Marsh Institute at Clark University. Published with Science in Society

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.