Solubility Sorption And Transport Of Hydrophobic Organic Chemicals In Complex Mixtures

Although toxicologic studies in the laboratory often focus on a single chemical, in the larger world, mixtures of chemicals are routinely encountered. Toxicology of Chemical Mixtures examines the mechanisms of interactions and health effects stemming from chemical mixtures in the environment. Toxicologists, pharmacologists, environmental scientists, and professionals involved in environmental clean-ups will benefit from its content. Emphasis is on low-level, long-term exposure. Key Features * Some of the issues addressed include: * Target organ toxicities in response to chemical mixture exposures * Risk assessment and experimental approaches * Case studies and special pollution problems * Special pollution problems

The Water Research Institute at the Technion (Israel Institute of Technology) is proud to have initiated and sponsored the International Workshop "Soil and Aquifer Pollution: Non-Aqueous Phase Liquids - Contamination and Recla- tion", held May 13th-15th, 1996, on the Technion campus in Haifa. Groundwater contamination is one of the pressing issues facing Israel and other countries which depend on groundwater for water supply. In Israel, 60% of the water supply comes from groundwater, most of it from two large aquifers. The Coastal Aquifer underlies the area where the largest concentration of human activity already takes place, and where much of future development is expected to occur. It is a phreatic sandstone aquifer, vulnerable to pollution from activities at the surface. The Mountain Aquifer is recharged in the higher terrain to the east, and flows, first in a phreatic zone, then confined, westward and underneath the Coastal Aquifer. This limestone aquifer has higher permeabilities and flow velo- ties, so pollution can reach the groundwater quite readily. Smaller local aquifers are also important components in the national water system. While measures are taken to protect these aquifers from pollution, there are locations where contamination has already occurred. Furthermore, accidental pollution may not be totally avoided in the future. Therefore, understanding the processes of groundwater contamination, recommending the proper measures for preventing it, and determining the best means for reclamation once pollution has occurred, are of great practical importance. Non-aqueous phase liquids (NAPLs) are among the most significant contaminants.

In March, 1983 a workshop on Pollutants in Porous Media was hosted by the Institute of Soils and Water of the Agricultural Research Organi zation in Bet Dagan, Israel. At this workshop, the unsaturated zone be tween the soil surface and groundwater was the focal point of discus sions for scientists from various disciplines such as soil chemists, physicists, biologists and environmental engineers. Since then, the prob lem of soil and water pollution has only worsened as more and more cases of pollution caused by human activities including agriculture and industry have been revealed. A great deal of work has been carried out by environmental scientists since 1983 in elucidating the behavior of the many classes of pollutants and the complex physical, chemical, and bio logical transformations which they undergo as they move through the soil to the vadose zone and, in many cases, the groundwater. In light of this, it was felt that another meeting of specialists from the many disciplines which deal with this subject was necessary and so a Second International Workshop on the Behavior of Pollutants in Porous Media, sponsored by IUPAC (the International Union of Pure and Applied Chemistry) and IAHS (the International Association of Hydrological Sciences), was organized and held in the Institute of Soils and Water of the Agricultural Research Organization in Bet Dagan, Israel during 1987. June, The present volume is a selection of the talks presented at this second workshop and deals only with toxic organic chemicals in porous media.

Several long-term trends in technology evolution have become apparent since these symposia began in 1989. Earlier presenters more frequently discussed treatment methods involving harsh and extensive human intervention. As the symposia have continued, the number of presentations describing extremely harsh and expensive treatment technologies have gradually been supplanted by more subtle and gentler methods. Such methods include subsurface-engineered barriers, phytoremediation, and bioremediation. Nineteen manuscripts were selected for inclusion in this volume, based upon peer review, scientific merit, the editors' perceptions of lasting value or innovative features, and the general applicability of either the technology itself or the scientific methods and scholarly details provided by the authors. General topics include: soil treatment, groundwater treatment, and radioactive waste treatment.