This guidebook provides theoretical and practical information for using a variety of isotope tracers for dating old groundwater, i.e. water stored in geological formations for periods ranging from about 1000 to one million years. Theoretical underpinnings of the methods and guidelines for their use in different hydrogeological environments are described. The guidebook also presents a number of case studies providing insight into how various isotopes have been used in aquifers around the world. The methods, findings and conclusions presented in this publication will enable students and practicing groundwater scientists to evaluate the use of isotope dating tools for specific issues related to the assessment and management of groundwater resources. In addition, the guidebook will be of use to the scientific community interested in issues related to radioactive waste disposal in geological repositories.

Groundwater Age is the first book of its kind that incorporates and synthesizes the state-of-the-art knowledge about the business of groundwater dating - including historical development, principles, applications, various methods, and likely future progress in the concept. It is a well-organized, advanced, clearly written resource for all the professionals, scientists, graduate students, consultants, and water sector managers who deal with groundwater and who seek a comprehensive treatment of the subject of groundwater age.

This book is a printed edition of the Special Issue "Environmental Tracers" that was published in Water

Environmental Tracers in Subsurface Hydrology synthesizes the research of specialists into a comprehensive review of the application of environmental tracers to the study of soil water and groundwater flow. The book includes chapters which cover ionic tracers, noble gases, chlorofluorocarbons, tritium, chlorine-36, oxygen-18, deuterium, and isotopes of carbon, strontium, sulphur and nitrogen. Applications of the tracers include the estimation of vertical and horizontal groundwater velocities, groundwater recharge rates, inter-aquifer leakage and mixing processes, chemical processes and palaeohydrology. Practicing hydrologists, soil physicists and hydrology professors and students will find the book to be a valuable support in their work.

There remains a lack of understanding of environmental isotopes and their use; students and practitioners typically find the concepts of isotope concentrations and partitioning to be more complicated than for geochemistry. However, this need not be so, if the basics are presented together with geochemistry, using case studies and examples to make the point. This new book presents the basics of environmental isotopes and geochemistry together, with case studies and simple examples that build a real understanding of their use in natural and contaminated groundwater.