This book provides the fundamentals for the understanding of reactive chemicals retention and their transport in soils and aquifers. The book offers the first comprehensive treatment with supporting examples of mathematical models that describe contaminants reactivity and transport in soils and aquifers. It is also a practical guide for designing experiments and collecting data that focuses on characterizing retention as well as release kinetic reactions in soils and contaminant transport experiments in the laboratory, greenhouse (column) and in the field.

H. Magdi Selim is Professor of Soil Physics and George and Mildred Caldwell Endowed Professor of Soil Science, School of Plant, Environmental and Soil Sciences at Louisiana State University at Baton Rouge. He received his B.S. degree in Soil Science from Alexandria University, Alexandria, Egypt, and his M.S. and Ph.D. in Soil Physics from Iowa State University, Ames, Iowa. Professor Selim is internationally recognized for his research in the areas of transport and kinetics of reactive chemicals in heterogeneous porous media and modeling of dissolved chemicals in water-saturated and unsaturated soils. He is the original developer of several conceptual models for describing the retention processes of dissolved chemicals in soils and natural materials in porous media. Pioneering work also include two-site and

multireaction and nonlinear kinetic models for trace elements, heavy metals, radio-nuclides, explosive contaminants, phosphorus and pesticides in soils and geological media.

Professor Selim is the author or coauthor of numerous scientific publications in several journals. He is author and co-author of several books. He is a member of the American Society of Agronomy, Soil Science Society of America, International Society of Soil Science, International Society of Trace Element Biogeochemistry, Louisiana Association of Agronomy, and American Society of Sugarcane Technology. Dr. Selim was elected chair of the Soil Physics Division of the Soil Science Society of America. He served on numerous committees of the Soil Science Society of America, American Society of Agronomy, and the International Society of Trace Element Biogeochemistry. He also served as associate editor of Water Resources Research and the Soil Science Society of America Journal and as Technical Editor of the Journal of Environmental Quality.

Professor Selim is a Fellow of the American Society of Agronomy and the Soil Science Society of America. Dr. Selim is the recipient of several professional awards and honors. Awards received include Phi Kappa Phi Research, Gamma Sigma Delta Award for Research, Joe Sedberry Graduate Teaching Award, First Mississippi Research Award, Doyle Chambers Achievements Award, and EPA Environmental Excellence Award. Recent awards include the Soil Science Research Award from the Soil Science Society of America (SSSA) and von Liebeg Award from the International Union of Soil Science (IUSS).

Soil-Chemical Interaction: Basic concept. Transport of Reactive Chemicals in soils: Basic concept. The Chemical Equilibrium in Approaches. The Multi-Reaction Transport Model (MRTM). The Second-Order Transport Model (SOTS). The mobile-immobile Chemical non-equilibrium model (MIM). Simulation of multiple chemical species in soils. Simulation of chemicals in heterogeneous media. Conclusion.