This textbook is aimed at students and professionals in environmental and chemical engineering, as well as those in disciplines related to chemical transport. It explores the challenges of estimating the transport and fate of chemicals released into the environment. The book applies the mathematics of diffusion, turbulent diffusion, and dispersion across various environmental media such as the atmosphere, rivers, groundwater, and oceans. The content is enriched with numerous case studies and examples to illustrate the theoretical principles and computational methods used in environmental transport modeling. The text is designed to develop practical skills in solving environmental transport problems and verifying computational solutions.