This document is the result of a conference on "Biological Monitoring of Metals" held in Rochester, June 2-6, 1986, organized jointly by the Environmental Health Sciences Center of the School of Medicine and Dentistry of the University of Rochester, NY, and the Scientific Committee on the Toxicology of Metals within the International Commission on Occupational Health (ICOH) at the Karolinska Institute and the National (Swedish) Institute of Environmental Medicine and the University of Umea, Sweden. The aim of the Conference was to define and evaluate the scientific basis for the biological monitoring of metals. The conference was co-sponsored by the World Health Organization through its International Program on Chemical Safety and received substantial encouragement and support from the Swedish Work Environmental Fund and the United States Environmental Protection Agency. This was the second conference organized jointly by the Scientific Committee on the Toxicology of Metals and The Toxicology Division of the University of Rochester. The previous joint conference was held in 1982 on the Reproductive and Developmental Toxicity of Metals. In addition, conferences have been organized by each group (see Appendices A and B). Several of these conferences are specially relevant to the topic of the current conference. These include the joint conference mentioned above and the conferences on dose-effect and dose-response relationship held in Tokyo in 1974 and on accumulation of metals held in Buenos Aires in 1972.

The importance of protecting the environment against pollution is an objective which gained international acceptance in the recent years. According to the first principle of the Declaration of the United Nations Conference on the Human Environment which took place in Stockholm in 1972, "man .... bears a solemn responsibility to protect and improve the environment for present and future genera tions." The United Nations again in their desire to improve the sanitation conditions allover the world decided to proclaim the period between 1981-1990 as the "International Drinking Water Supply and Sanitation Decade." Although attempts have been made by inter national organizations to prevent pollution, it is difficult to say that these attempts gave satisfactory results in developing countries. The most common reasons of failure are: a) To find solutions to their environmental problems, develop ing countries usually seek the assistance of engineers and scientists from developed countries. Many times, how ever, either out of ignorance of the local condition or due to financial motivations, these experts come out with solutions which are far from being considered as the "most appropriate." As a result, the basic objective of protecting the environment is not achieved. b) Attempts made by developed countries to "export" their wastes - especially the hazardous ones - to the developing world, is another danger - and sometimes reason of failure encountered in the field of Environmental Management."

In 1982, three conservationists in the United States discussed a growing concern they shared about the long-term biological consequences of nuclear war; they wondered what such a war would do to the air, the water, the soils 1 the natural systems upon which all life depends. I was one of those three; the others were executives of two philanthropic foundations, Robert L. Allen of the Henry P. Kendall Foundation and the late Robert W. Scrivner of the Rockefeller Family Fund. Together we began trying to find out what the scientific community was doing about the problem and what steps could be taken to alert the environmental movement to the need to address the subject. We knew that a large-scale nuclear war might kill from 300 million to a billion people outright and that another billion could suffer serious injuries requiring immediate medical attention, care that would be largely unavailable. But what kind of world wouldisurvivors face? Would the long-term consequences prove to humanity and survival of all species than the to be even more serious immediate effects? We found that comparatively little scientific research had been done about the envifonmental consequences of a nuclear war of the magni tude that toda, y's huge arsenal could unleash . ."

Reservoirs for Wastewater Storage and Reuse is a compendium of available information on this emergent technology, from the role that wastewater reservoirs can play within general water resources management and wastewater reuse policy, to the design and operation of the units, including removal efficiencies for different pollutants. Furthermore, a detailed description of the ecological structure and function of the ecosystem of reservoirs is given. This book summarizes more than 20 years of research and development in Israel where more than 200 of these reservoirs are in operation. It includes both theoretical developments and practical experience gained by designers, operators and farmers. Potential geographic areas for the use of these reservoirs are the whole Mediterranean region, the Pacific coasts of both South and North America, the Atlantic coasts of Africa, the Middle East, and other regions suffering water shortage.

Volume 9 of Chemical Mutagens consists mainly of chapters discussing the development and validation of short-term assays to detect the mutagenic effects of environmental chemicals. These chapters include an assay with the grasshopper neuroblast, a comparison of mutagenic responses of human lung-derived and skin-derived diploid fibroblasts, a forward-mutation assay in Salmonella, a multigene sporulation test in Bacillus subtilis, a specific locus assay in mouse lymphoma cells, a study of the induction of bacteriophage lambda, and the granuloma pouch assay. In addition, there are two chapters on the identification of mutagens in cooked food and in human feces. Frederick 1. de Serres Research Triangle Park, North Carolina vii Contents Chapter 1 The Grasshopper Neuroblast Short-Term Assay for Evaluating the Effects of Environmental Chemicals on Chromosomes and Cell Kinetics 1 Mary Esther Gaulden, Jan C. Liang, and Martha J. Ferguson 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. Embryo Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. 1. Species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. 2. Origin of Colonies . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. 3. Life Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 4. Colony Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. 5. Pathology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2. 6. Allergy to Grasshoppers . . . . . . . . . . . . . . . . . . . . . . 14 3. Grasshopper Egg, Embryo, and Cells . . . . . . . . . . . . . . . . . 14 3. 1. The Egg Shell and Membranes . . . . . . . . . . . . . . . . . 14 3. 2. Embryonic Development . . . . . . . . . . . . . . . . . . . . . . 17 3. 3. Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4. Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4. 1. Exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4. 2. Preparation of Embryos for Cell Analysis . . . . . . . . . 34 4. 3. Analysis of Mutagen Effects. . . . . . . . . . . . . . . . . 40 . . . 5. Response of the Grasshopper Neuroblast to Mutagens . . . . 50 5. 1. Reproducibility of Data . . . . . . . . . . . . . . . . . . . . . . . 50 5. 2. Radiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 5. 3. Chemical Mutagens . . . . . . . . . . . . . . . . . . . . . . . . . .

From beach encounters, aquaculture perils, and processed-food poisoning to snake bites and biological warfare, natural toxins seem never to be far from the public's sight. A better understanding of toxins in terms of their origin, structure, structure-function relation ships, mechanism of action, and detection and diagnosis is of utmost importance to human and animal food safety, nutrition, and health. In addition, it is now clear that many of the toxins can be used as scientific tools to explore the molecular mechanism of several biological processes, be it a mechanism involved in the function of membrane channels, exocytosis, or cytotoxicity. Several of the natural toxins have also been approved as therapeutic drugs, which has made them of interest to several pharmaceutical companies. For example, botulinum neurotoxins, which have been used in studies in the field of neurobiology, have also been used directly as therapeutic drugs against several neuromus cular diseases, such as strabismus and blepherospasm. Toxins in combination with modem biotechnological approaches are also being investigated for their potential use against certain deadly medical problems. For example, a combination of plant toxin ricin and antibodies is being developed for the treatment of tumors. The great potential of natural toxins has attracted scientists of varying backgrounds-pure chemists to cancer biologists-to the study of fundamental aspects of the actions of these toxins."

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.

The atmospheric scientists of the world are in general agreement that the threat of climate change is real, inevitable, and serious. The accumulation of greenhouse gases, principally CO from burning fossil fuels, is the main cause. 2 At the 1992 United Nations Conference on Environment and Development in Rio de Janeiro, 166 nations signed the Framework Convention on Climate Change and agreed to draw up plans to contain greenhouse gases at 1990 levels. Never in world history had so many nations agreed on anything. . Developing these plans has not been easy and no two countries have had the same circumstances and conditions to meet. Countries have not approached their problems in the same manner and many nations find the task almost impossible to solve under the ground rules set up in Rio. This volume contains the papers presented at a meeting organized by the Center for Environmental Information and held in Washington, D.C., November 30 to December 2, 1994. The principal aim of the meeting was to evaluate the U.S. and other national climate action plans which had been released a few weeks before. Specifically, these papers concentrate on an overview of the U.S. plan; the perspec tives of business, industry, electric utilities, and environmental organizations; mitigation actions in various plans; integrated assessment; an overview of plans from various nations; and the need to amend the convention. The meeting was sponsored and cosponsored by 35 governmental agencies, environ mental groups, industrial organizations, and educational institutions."

This volume constitutes the proceedings of the Produced Water Seminar held in Trondheim, Norway, in September 1995. Hosted by Statoil Research and Development and IKU Petroleum Research, the seminar was an update of the 1992 seminar of the same title held in San Diego, California (Ray and Engelhardt, 1992). Produced water remains the largest volume waste stream from oil and gas production offshore. In the North and Norwegian Seas, produced water volumes are projected to increase significantly over the coming decades, as oil reservoirs near depletion. These releases are therefore the focus of continuing environmental concern. The purpose of this seminar was to provide a forum for scientists, legislators, and industrial and environmental representatives to share recent information and research results, and to encourage cooperative pursuit of solutions in the future. The success of the seminar, and the quality of this volume, are due in large part to the many authors from around the world who presented almost 50 posters and papers focused on environmental issues and mitigation technologies. In addition, we wish to acknowledge the contributions of the local and international organizing committees. Local Committee Asbj0fg 0verli and Heidi Torp, Statoil Egil Wanvik and Laila S. Olden, IKU Petroleum Research International Committee James P. Ray, Shell Chemical and Petroleum Products Companies Alexis E. Steen, American Petroleum Institute Theodor C. Sauer, Battelle Ocean Sciences Steven A. Flynn, British Petroleum Martin C. Th. Scholten, TNO Kjell Lohne, Statoil Ingvild Martinsen, Norwegian Pollution Control Authority.

The study of the relationship between environmental pollution and human health is in its infancy. The number of substances and mixtures that have been identified in uncontrolled hazardous waste sites or that have been in advertently released into the environment is large and data on how thes~ substances are modified as they interact with one another as they migrate through soil, air, and water are limited. There are also limits on our un derstanding of how these substances may be ingested, inhaled, or absorbed by people. The complexity of possible interactions between biological, chemical, and physical components in a given environment makes it virtually impossible to evaluate the potential for adverse biological effects ade quately in the laboratory. Other, more comprehensive methods which provide realistic and interpretable results must be used. Many scientists believe that humans represent the ultimate sentinel species of a toxic exposure re sUlting from environmental pollution, however such exposures may also se verely impact environmental health. There exists a wide variety of organ isms in the natural environment that could be used to provide an early warning for potential human health effects as well as to indicate adverse ecological effects. The issue of effective utilization of sentinel species for environment al monitoring is a rapidly developing area of research which has grown in importance during the last decade.

The pilot study on estuarine management was initiated by the NATO Committee on the Challenges of Modem Society (CCMS). The objective of this project was to make a comparison of several estuarine management strategies and to formulate a set of recommen dations and planning guidelines to restore polluted estuaries, to prevent further estuarine deterioration, and to manage conflicting demands stemming from human activities. The first results of this NATO-CCMS project were reported in 1982, describing six estuaries and their management approaches. In 1985 CCMS decided a subsequent research project should be performed to achieve the original objectives. This second research project was basically done by way of a comprehensive questionnaire that was sent to authorities of estuarine areas all over the world. Eleven questionnaires have been received. In some instances, the questionnaires were not fully completed for several reasons. Especially, data on water quality was lacking. As a result, less attention will be paid to related aspects as originally intended. This study shows that knowledge of the number of functions and conflicts of estuaries may provide relevant information concerning the severity of the problems as well as the propensity towards planning of water systems."

***e FACHGEBIET*** Mathematical Geology, Computer Applications, Artificial Intelligence, Urban Economics and Regional Economics ***INTERESSENTENGRUPPE*** Of interest to Urban and Regional planners, civil engineers, geographers; computer scientists; operations researchers; landscape architects; and advanced students in the above disciplines.- Level: Technical Book, Monograph ***URHEBER*** T.J. Kim, University of Illinois, Champaign, IL; L.L. Wiggins, Massachusetts Institute of Technology, Cambridge, MA; J.R. Wright, Purdue University, Lafayette, IN (Eds.) ***TITEL*** Expert Systems: Applications to Urban Planning ***BIBLIOGRAPHISCHE-ANGABEN*** 1990. XIV, 268 pp. 48 figs. Hardcover DM 78, - ISBN 3-540-97171-8 ***LANGTEXT*** While expert systems have become a popular topic in the computing, medical and engineering fields, the expert system is still a new technology in urban planning. This book introduces expert systems for problem solving in urban planning and describes the way in which heuristic knowledge and rules of thumb of expert planners can be represented through computer programs. The book presents practical applications of expert systems for solving many important urban planning problems, particularly those issues that many practicing planners face in their daily operations. Problems and issues discussed are grouped in the following categories: - Land Use Planning - Transportation Planning - Site Selection and Analysis - Environmental Planning - Conflict Mediation and Legal Disputes - Future Developments and Directions Expert Systems: Applications to Urban Planning will benefit both urban planners who wish to learn how this new technology might be applied to their daily work as well as researchers in expert systems seeking new ideas for systems design.

Biotechnology for Waste Management and Site Restoration covers: waste management - solid, gaseous, liquid; site restoration - radioactivity, organics, toxic metals; educational, economic, social and business aspects; and international collaboration. International collaboration is growing apace and many concrete projects have been started. The body of knowledge is growing. Over the long term, it is envisaged that this international collaboration will result in a long-term scientific and technological strategy, new technologies and alternative solutions, and practical implementations of biotechnology for the nuclear and industrial sectors of the economy.

Although present day politics seems to be preoccupied with questions of economic growth and full employment, the basic environmental problems stemming from the interactions of the economic sphere with global, regional and local environments persist and will have an even greater impact in the future. If economy and ecology are not reconciled in the years to come, mankind will not have a sustainable future on Earth. The typical negation of environmental problems in times of economic crisis is partially due to the fact that environmental and health damages of economic activities are neither priced nor included in our market price system. This allows politicians to focus their attention on insufficient economic indicators which do not reflect the actual development of the welfare of society. If economic lead indicators like GDP or balance of trade figures were better integrated with information on the environmental and health costs caused by the seemingly beneficial economic development, politicians might have better guidance as to what policy choices would benefit society most.

The Council of the North Atlantic Treaty Organization (NATO) established the "Committee on the Challenges of Modern Society" (CCMS) in 1969. The CCMS was charged with developing meaningful environmental and social programmes for solving existing problems and developing long-range goals for environmental protection. In 1983, at the Fall Plenary of the CCMS, the Norwegian delegate Dr. H.C. Christensen, proposed a Pilot Study on "Risk Management of Chemicals in the Environment". A draft proposal, written by Dr. Kari Kveseth of the Center for Industrial Research in Oslo, was presented. Dr. Christensen also informed the participants at the meeting that Norway was willing to act as the Pilot Country. The project was initially planned for 3 years, but it was later extended through 1987. The inaugural meeting was held in Oslo in April 1984 with participants from Denmark, Greece, France and Italy, in addition to representatives from several Norwegian institutions. The attendees concluded that a Pilot Study, as delineated in the draft proposal, would be useful, and it was decided to work out a detailed project plan based on the proposal.

During the past few years the worlds has reverberated of names like Seveso, Love Canal, Lekkerkerk, Times Beach, just to name the most publicized ones. All these names are connected with hazardous or toxic waste, waste from business and industry, especially the chemical industry. The list is endless because there are, all over the world, many thousands of "points noirs" not yet discovered or identified old lagoons and landfills, polluted rivers, estuaries, and harbors needing remedial action, which undoubtedly will reveal more unpleasant secrets of the chemical industry's past. It is not an exaggerated statement that chemists of the past have paid too much attention to the composition of new products while neglecting the disposition of byproducts, i.e., chemical waste. Admittedly, during the last decade this attitude has changed dramatically. Although we cannot yet properly speak of a new science of peri ontology (the theory of residues), we seem to be headed towards substantiated rules, analyses, disposal protocols, definitions and remedial practices in handling the problems of chemical waste. Especially during the last two years comprehensive treatises of the whole complex subject as well as monographs dealing with assorted aspects of waste tech nology have appeared."

During late 1978, a symposium entitled "Science Underlying Radioactive Waste Management" was one component of the Annual Meet ing of the Materials Research Society held in Boston, Massachusetts. The purpose of this Symposium was to bring together for the first time the entire range of sciences that form the basis for the treatment, solidification and isolation of radioactive wastes. Some 79 papers were presented to an international audience of over 300. The Symposium was such an impressive success that another will be held at the 1979 Annual Meeting of the Materials Research Society. The proceedings of the forthcoming symposium will also be published and it is for this reason that the present volume has been desig nated Volume 1. The scope of the Symposium was defined by the following steer ing committee: Rustum Roy, The Pennsylvania State University (Chairman) Richard S. Claassen, Sandia Laboratories Don Ferguson, Oak Ridge National Laboratory Victor I. Spitsyn, U.S.S.R. Academy of Sciences, Moscow David B. Stewart, United States Geological Survey Torbjorn Westermark, Royal Institute of Technology, Stockholm. The program was organized by the following committee: Gregory J. McCarthy, The Pennsylvania State University (Cha- man) Harry C. Burkholder, Battelle Memorial Institute Arnold M. Friedman Argonne National Laboratory Werner Lutze, Hahn-Meitner Institut, Berlin John G. Moore, Oak Ridge National Laboratory Robert W. Potter, II, United States Geological Survey Richard L. Schwoebe1, Sandia Laboratories Roger W. Staehle, Ohio State University."

Metals in the hydrological cycle represent a very broad subject covering all parts of the geological cycle. The present version of this book, therefore, would not have been possible without the comments and suggestions for improvement on draft ver- sions of the various chapters by a large number of colleagues. We wish to express our gratitude to: P.A. Cawse (AERE, UK), J.N. Galloway (University of Virginia, USA) and S.E. Lindberg (Oak Ridge National Labo- ratory, USA) for reviewing the chapter on atmospheric trace metals. G. Batley (CSIRO, Australia) and B.T. Hart (Chisholm In- stitute of Technology, Australia) for reviewing the chapter on speciation of dissolved metals. E.K. Duursma (Delta Institute, The Netherlands), J.M. Bewers and P.H. Yeats (Bedford Institute of Oceanography, Canada) and D. Eisma (Netherlands Institute for Sea Re- search, the Netherlands) for reviewing the chapter on estuaries. P. Baccini (EAWAG, Switzerland) and W. Davison (Fresh- water Biological Association, UK) for reviewing the chapter on lakes. E.T. Degens (University of Hamburg, W-Germany) for re- viewing the chapter on the oceans, and J.P. Al (Public Works Department, The Netherlands) for reviewing most of the indi- vidual chapters. Without the collaboration of these colleagues this book would not have been possible in its present form.

The problem of pollution of the environment arose for the first time with the beginning of Industrialization. At that time there was no need to think about disposal of waste. There was no reason to do so because the space available to man and other living creatures appeared quite adequate. The life expectancy of man has risen as a result of the enormous advances In technology and medicine. In 1650 It was 30 years throughout the world whi Ie In 1970 It had risen to 53 years, and this has consequently been accompanied by a population exp los I on. Whl Ie the world population in 1650 was some 500,000,000, in 1970 It was about 3,600,000,000. Assuming that mortality does not rise sharply, the population potential 1 for the year 2000 is expected to be some 7,000,000,000 * Industrial production has grown to an even greater degree than the world population. The growth of noxious substances has developed with the growth of the population on the one hand and with industrial growth on the other. The growth of slaughterhouse waste is directly related to population growth, because as the population -increases so does the demand for meat and meat products. Consumption habits have also changed with Increasing prosperity so that there has been an increase in the proportion of slaughterhouse by-products which are difficult to market.

The volume contains the main papers presented at the 1994 EUROTOX Congress, Basel, Switzerland, August 21-24, 1994. Toxicology has become a less descriptive science because more importance has been placed on the mechanisms underlying toxic effects. This is reflected in symposia and workshops devoted to species differences in organ toxicity, receptor-mediated toxicity and stereochemical effects of xenobiotics. Recent progress in the fields of immunotoxicology, ecotoxicology, and neurotoxicology is highlighted and documented together with the present discussion on harmonized regulatory guidelines.

The past few years have seen the emergence of a growing, widespread desire in this country, and indeed everywhere, that positive actions be taken to restore the quality of our environment, and to protect it from the degrading effects of all forms of pollution-air, noise, solid waste, and water. Since pollution is a direct or" indirect consequence of waste, if there is no waste, there can be no pollution, and the seemingly idealistic demand for" zero discharge" can be construed as a demand for zero waste. However, as long as there is waste, we can only attempt to abate the consequent pollution by converting it to a less noxious form. In those instances in which a particular type of pollution has been recognized, three major questions usually arise: 1, How serious is the pollution? 2, Is the technology to abate it available? and 3, Do the costs of abatement justify the degree of abatement achieved? The principal intention of this series of books is to help the reader to formulate answers to the last two of the above three questions. The traditional approach of applying tried-and-true solutions to specific pollution problems has been a major factor contributing to the success of environmental engineering, and in large measure has accounted for the establishing ofa "methodology of pollution control.

"Heavy Metals: Problems and Solutions" is divided into three sections dealing with basic geochemical processes, remediation and case studies. The basic geochemical processes are discussed with respect to mobility in the environment and impact as well as methods to derive guidelines for heavy metals. Remediation focuses on currently available methods to treat contaminated sediments and soils. In addition, it considers the concept of geochemical engineering for remediation of large areas contaminated by metals. A number of case studies of polluted sediments and soils and their environmental impact highlight the principles discussed in the first two sections.

The object of sludge characterization must be to get quantitative mea- sures for sludge behaviour in treatment processes and when disposed of. Thus the incentive for characterization could be one of the following: 1. Because sludges exist in large quantities we want to know the amounts and the expenees involved in their treatment and disposal. 2. Because sludges are environmental nuicances/hazards, energy sourc:-es, fertilizers or even food sources; we want to know their potential. 3. Because the processes change the sludge propert~es, we w~nt to know their "treatability". 4. 5ecause sludges have a history, we want to know how the generation process affects the quantities and the properties of raw sludge. Parallel to the characterization of the sludges runs characterization of the sludge treatment-processes and the environment in which we dispose of the sludge. In the following discussion we will group parameters related to sludges into three cathegories: 1. Sludge Quantity. Both total ~nd per capita sludge production data from all connnon sewage and sludge treatment methods are of "interest. 2. Treatability parameters. These are characteristics of how a sludge behaves in a specific process. Typically; dewaterability and digesta- bility. 3. Sludge quality parameters. These are indicators of how the sludge could influence the environment when disposed of. Sludge quality changes through most sludge treatment processes (stabilization, ther- mal etc.) and include concentrations of chemical compounds, pathogenes etc.

The first Symposium on Recent Advances in Problems of Flow and Transport in Porous Media was held in Marrakech in June '96 and has provided a focus for the utilization of computer methods for solving the many complex problems encountered in the field of solute transport in porous media. This symposium has been successful in bringing together scientists, physicists, hydrogeologists, researchers in soil and fluid mechanics and engineers involved in this multidisciplinary subject. It is clear that the utilization of computer-based models in this domain is still rapidly expanding and that new and novel solutions are being developed. The contributed papers which form this book reflect the recent advances, in particular with respect to new methods, inverse problems, reactive transport, unsaturated media and upscaling. These have been subdivided into the following sections: I. Numerical methods II. Mass transport and heat transfer III. Comparison with experimentation and simulation of real cases This book contains reviewed articles of the top presentations held during the International Symposium on Computer Methods in Porous Media Engineering which took place in Giens (France) in October 1998. All of the presentations and the optimism shown during the meeting provided further evidence that computer modeling is making remarkable progress and is indeed becoming an essential toolkit in the field of porous media and solute transport. I believe that the content of this book provides evidence of this and furthermore gives a comprehensive review of the theoretical developments and applications.