Chemical Fate and Transport in the Environment, Fourth Edition explains the fundamental principles of mass transport, chemical partitioning, and chemical/biological transformations of pollutants and naturally occurring chemicals in surface waters, in the subsurface (which includes soil and groundwater), and in the atmosphere. Each of these three major environmental media is introduced by a descriptive overview, followed by presentations of the governing physical, chemical, and biological processes. The text emphasizes intuitively based mathematical models for chemical equilibria, transformations, and transport in the environment. This book serves as a primary text for graduate and senior undergraduate courses in environmental science and engineering, provides relevant scientific knowledge for students of public health and environmental policy, and is a useful reference for environmental practitioners. This fourth edition builds on the third edition, which won a 2015 Textbook Excellence Award (Texty) from The Text and Academic Authors Association. This updated textbook expands the discussion of global climate change, presents concepts of stationarity and sustainability, provides additional coverage of wastewater treatment and air pollution abatement technologies, and includes information on additional anthropogenic pollutants such as plastics, PFAS, and nanoparticles. Tables, figures, and references are updated, and worked examples and practice exercises are included for each chapter.