Christos Tsadilas, PhD, is a senior researcher of the Institute of Industrial and Forage Crops of the General Directorship of Agricultural Research of the Hellenic Agricultural Organization DEMETER, a public entity supervised by the Ministry of Rural Development and Foods of Greece. He graduated from the Agricultural University of Athens in 1975 and earned his master's degree and PhD from the same university. From 1977 to 1984, he worked at the Institute of Soil Mapping and Classification of the Ministry of Rural Development and Foods as a soil surveyor, and has been a senior scientist of the National Project of Soil Survey Mapping in Greece. Later, he worked as a researcher at the National Agricultural Research Foundation in Greece, which later merged with the current Hellenic Agricultural Organization DEMETER. He has taken post doc studies at the University of Reading (United Kingdom), University of Kentucky, and University of Lincoln (Nebraska), sponsored by the Royal Society of England, OECD, and the Fulbright Foundation, respectively. His main research interests include soil survey and classification, soil chemistry and fertility, soil pollution and remediation, and waste management. He also has work experience on land reclamation of disturbed lands. In the past few years, he has started to deal with the new technologies used in precision farming systems. Dr. Tsadilas is a well-known researcher in the field of trace elements in soils, having published more than 250 papers in peer-reviewed journals, chapters in books, and papers in international conference proceedings. A special mention is made on the book The Soils of Greece (Yassoglou, Tsadilas, and Cosmas, 2017, Springer). He has served as associate editor for several journals including Environmental Pollution, Communications in Soil Science and Plant Analysis, Advances in Agriculture, and the African Journal of Agricultural Research. He also served as president of the Hellenic Soil Science Society for several years. Joerg Rinklebe, PhD, is a professor in soil and groundwater management at the University of Wuppertal, Germany. From 1997 to 2006, he worked as a scientist, research associate, and project leader in the Department of Soil Sciences at the UFZ (Centre for Environmental Research), Leipzig-Halle, Germany. Dr. Rinklebe studied ecology for one year at the University of Edinburgh, Scotland (1992-1993). He studied agriculture, specializing in soil science and plant nutrition, at Martin Luther University Halle-Wittenberg, Germany, where he earned a PhD in soil science. His main research is on wetland soils, sediments, waters, plants, and their pollution (trace elements and nutrients) and linked biogeochemical issues, with a special focus in redox chemistry. He also has expertise in remediation of toxic element-contaminated soils and soil microbiology. Dr. Rinklebe is internationally recognized for his research in the areas of biogeochemistry of trace elements in wetland soils. He has published numerous scientific papers in leading international and national journals, a book, Trace Elements in Waterlogged Soils and Sediments (2016), as well as numerous book chapters. He serves as associate editor of the international journal Environmental Pollution and as a guest editor of the international journals: Journal of Hazardous Materials, Environment International, Science of the Total Environment, Chemosphere, Journal of Environmental Management, Applied Geochemistry, and Environmental Geochemistry and Health. In addition, he is a member of several editorial boards including Ecotoxicology, Geoderma, Water, Air, & Soil Pollution, and Archive of Agronomy and Soil Science, and is a reviewer for many international journals. He has organized several special symposia at various international conferences such as Biogeochemistry of Trace Elements (10th, 11th, 12th, 13th, and 14th ICOBTE) and the International Conference on Heavy Metals in the Environment (15th, 16th, 17th, 18th, and 19th ICHMET). He has been an invited speaker (plenary and keynote) at many international conferences. In October 2016, he was appointed as honorable ambassador for Gangwon Province, South Korea. Since March 2017, he has been a visiting professor at the Department of Environment and Energy at Sejong University, Seoul, South Korea, and a guest professor at the Department of Environmental Engineering, China Jiliang University, Hangzhou, Zhejiang, China. H. Magdi Selim, PhD, 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 BS degree in soil science from Alexandria University, Alexandria, Egypt, and his MS and PhD in soil physics from Iowa State University, (Ames, Iowa). He is internationally recognized for his research in the areas of kinetics of reactive chemicals in heterogeneous porous media and transport modeling of dissolved chemicals in water-saturated and unsaturated soils. He is the original developer of several models for describing the retention processes of chemicals in soils. Pioneering work also includes multistep/multireaction and nonlinear kinetic models for trace elements, heavy metals, radionuclides, explosive contaminants, phosphorus, and pesticides in soils. Other research areas include water quality, soil health, and the fate of applied agricultural chemicals in soils at different scales, as well as best management practices that minimize nutrient and soil loss under different agricultural management. Dr. Selim is the developer of Chem_Transport, a software package of models that describe the fate and transport of reactive chemicals and tracers in soils and geological media. The models represent recent advances made toward the understanding of transport characteristics of chemicals in soils with an emphasis on physical and chemical nonequilibrium. Dr. Selim is the author or coauthor of numerous scientific publications in several journals. He is also editor and coauthor of several books. Dr. Selim is the recipient of several professional awards and honors. He is a member of the American Society of Agronomy, the Soil Science Society of America, the International Society of Soil Science, the International Society of Trace Element Biogeochemistry, the Louisiana Association of Agronomy, and the American Society of Sugarcane Technology. Dr. Selim was elected chair of the Soil Physics Division of the Soil Science Society of America. He has served on numerous committees of the Soil Science Society of America, the 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.