This book concerns applications of geochemical modeling to “real-world” environmental problems and issues. What makes the environmental problems and issues real is that federal and state environmental regulations mandate certain actions being taken to prevent, reduce, or remediate environmental pollution. The fact that environmental work is performed within a regulatory framework is essential to the understanding of the role of geochemical modeling and geochemistry in general. It must be understood that environmental work has been, is being, and will be carried out to comply with various regulations every day, regardless of how imperfect our models are or how limited our knowledge might be. Society has a need: human health is at risk, and the environment is deteriorating. Neither situation can afford to wait for scientists to provide all the answers or to wait for agreement before any actions are taken. We think the only course of action is to put the best science available in the hands of environmental specialists.

It is, therefore, an objective of this book to bridge the two worlds, academic research and environmental practice, that seem ever apart. We want to provide a guide on geochemical modeling for practicing geochemists, hydrogeologists, engineers, and regulators. Most practitioners in the environmental field lack formal training in geochemical modeling but have to work under stringent deadline, budget, and regulatory constraints. We hope that this book – with its balanced focus on geochemical background, computer programs, and real-world case studies – will serve as a desktop reference for them.