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.

Inhalt

I: Overview of the Problem.- Introductory Comments.- 1 Dimensions of Ground Water Pollution: A Global Perspective.- 1.1 Water Management Misfortunes.- 1.2 The Emerging Perception of Quality Decline.- 1.3 Man's Impact on Ground Water '.- 1.4 A Current Assessment of Ground Water Pollution.- 1.5 Changing Patterns of Waste Disposal.- 1.6 Legislative Controls.- 1.7 The Cleanup.- 1.8 Public Perception.- 1.9 The Professional's Responsibility to the Public.- 1.10 Reasonable Risk.- 1.11 The Future.- 2 Pollution Hazards from Toxic Organic Chemicals.- 2.1 Introduction.- 2.2 The Facts.- 2.2.1 Pesticides in Groundwater.- 2.2.2 Industrial Chemicals in Groundwater.- 2.2.3 Wastewater.- 2.2.4 Mathematical Modelling of Groundwater Contamination.- 2.3 Conclusions.- 2.4 Recommendations.- References.- II: Physicochemical and Biological Interactions with Porous Media.- Introductory Comments.- 3 Interactions of Toxic Organic Chemicals with Humic Substances.- 3.1 Introduction.- 3.2 Soil and Aquatic Humic Substances.- 3.2.1 Introduction.- 3.2.2 Interactive Properties of Humic Substances.- 3.3 Toxic Organic Chemicals.- 3.3.1 Pesticides.- 3.3.2 Polynuclear Aromatic Hydrocarbons.- 3.3.3 Phthalates.- 3.4 Evidence of Interactions of TOC with Humic Substances.- 3.4.1 Soil.- 3.4.2 Waters.- 3.4.3 Sediments.- 3.5 Modes of Interaction of Humic Substances with Toxic Organic Pollutants.- 3.5.1 Adsorption.- 3.5.2 Partitioning.- 3.5.3 Solubilization Effects.- 3.5.4 Hydrolysis Effects.- 3.5.5 Photosensitization.- 3.6 Conclusions and Recommendations.- References.- 4 Surface Interactions of Toxic Organic Chemicals with Minerals.- 4.1 Introduction.- 4.2 Relevant Properties of the Mineral Components of the Solid Phase.- 4.3 Interrelation Between Components of the Solid Phase.- 4.4 The Exchange Complex.- 4.5 Interrelations Between the Phases.- 4.6 Surface Enhanced Transformations.- 4.7 Factors Affecting Surface Interactions.- 4.7.1 Temperature.- 4.7.2 Moisture Content.- 4.7.3 Intrinsic Properties of the Solid Phase.- 4.7.4 The Composition of the Exchange Complex.- 4.7.5 Other Factors.- 4.8 Mechanisms and Kinetic Considerations.- 4.8.1 A Two Phase (Solid-Liquid) System in Which the Adsorption of the Reactant Follows a Linear Adsorption Isotherm.- 4.8.2 A Two Phase (Solid-Liquid) System in Which the Catalytically Active Surface Sites are Saturated with the Reactant.- 4.8.3 A Porous Medium not in Contact with a Free Liquid Phase.- 4.9 A Unified Description of Surface Interactions.- 4.10 Enzymatic Reactions.- 4.11 General Discussion and Conclusions.- References.- 5 Abiotic Transformations of Toxic Organic Chemicals in the Liquid Phase and Sediments.- 5.1 Introduction.- 5.2 Transformations in the Water Column.- 5.3 Transformations in Sediments.- 5.3.1 Hydrolysis.- 5.3.2 Redox Reactions.- 5.4 Transformations in Groundwaters.- 5.4.1 Hydrolysis.- 5.4.2 Redox Reactions.- 5.5 Future Direction.- References.- III: Pesticides in Porous Media.- Introductory Comments.- 6 Predicting the Mobility and Availability of Toxic Organic Chemicals.- 6.1 Introduction.- 6.2 Current Methods for Predicting Adsorption.- 6.3 Molecular Connectivity.- 6.4 MC-SAR Studies.- 6.5 The Need for Future Work.- 6.6 Summary.- References.- 7 Partition and Adsorption on Soil and Mobility of Organic Pollutants and Pesticides.- 7.1 Introduction.- 7.2 Sorption by Soil in Aqueous Systems.- 7.3 Sorption by Soil from Organic Solvents.- 7.4 Sorption by Soil from the Vapor Phase.- 7.5 Influence of Soil Sorption on Pollutant and Pesticide Activity.- References.- 8 Sorption and Transport of Organic Pollutants at Waste Disposal Sites.- 8.1 Introduction.- 8.2 Solubility in Complex Solvents.- 8.2.1 Solubility in Mixed Solvents.- 8.2.2 Solubility in Multi-Phasic Solvents.- 8.3 Sorption from Complex Solvents.- 8.3.1 Sorption from Mixed Solvents.- 8.3.2 Sorption from Biphasic Solvents.- 8.3.3 Sorption from Complex Solvents Containing PMOS and CMOS.- 8.4 Sorption from Aqueous Solutions of Multi-Sorbate Mixtures.- 8.5 Transport in the Presence of Complex Solvents.- 8.5.1 Transport in Mixed Solvents.- 8.5.2 Transport in Biphasic Solvents.- 8.5.3 Transport in Miscible and Immiscible Solvents.- 8.6 Transport of Mixtures of Organic Pollutants.- References.- 9 Accelerated Degradation of Pesticides.- 9.1 Introduction.- 9.2 Accelerated Degradation of Pesticides.- 9.3 Assessment of Accelerated Degradation.- 9.4 Mechanisms of Accelerated Degradation.- 9.5 Persistence of Accelerated Degradation.- 9.6 Cross Accelerated Degradation.- 9.7 Control and Management of Accelerated Degradation.- 9.8 Conclusions and Prospects.- References.- IV: Petroleum Hydrocarbons.- Introductory Comments.- 10 On the Behavior of Petroleum Hydrocarbons in the Unsaturated Zone: Abiotic Aspects.- 10.1 Introduction.- 10.2 Properties of the Interacting Materials.- 10.2.1 Crude Oils and Petroleum Products.- 10.3 Partitioning Between Gaseous, Aqueous, and Solid Phases.- 10.3.1 Migration into the Gaseous Phase.- 10.3.2 Dissolution in the Water Phase.- 10.3.3 Retention by the Solid Phase.- 10.4 Surface Degradation.- 10.5 Multiphase Transport.- 10.6 Conclusions.- References.- 11 Transport of Organic Pollutants in a Multiphase System.- 11.1 Introduction.- 11.2 Classification of LH According to Contamination Criteria.- 11.3 Introduction of the Pollutant into the Subsurface Water.- 11.4 Migration of LHin the Unsaturated Zone.- 11.5 Migration of LH in the Saturated Zone.- 11.6 Modelling Procedures.- 11.6.1 Gross Control Volumes.- 11.6.2 Differential Control Volumes Referring to the Whole Flow Field.- 11.6.3 Differential Control Volumes Referring to Various Parts of the Flow Field.- 11.7 Determination of the Flow Field Characteristics.- 11.8 Practical Aspects.- References.- 12 Biochemical Aspects of Hydrocarbon Biodegradation in Sediments and Soils.- 12.1 Introduction.- 12.2 Biochemical Considerations.- 12.3 Application of Results of Biochemical Considerations.- 12.4 Laboratory Experiments with Fresh Marine Sediment.- 12.5 Laboratory Experiments with a Standardized and Inoculated Sediment Mixture.- 12.6 Anaerobic Degradation.- 12.7 Hydrocarbon Biodegradation in Soils.- 12.8 Conclusions.- References.- V: Restoration of the Unsaturated Zone and Groundwater.- Introductory Comments.- 13 Manipulation of the Vadose Zone to Enhance Toxic Organic Chemical Removal.- 13.1 Introduction.- 13.2 Physical Methods.- 13.2.1 Leaching.- 13.2.2 Enhanced Volatilization.- 13.2…