Water pollution techniques and practices, including data analysis, interpretation and display are described in this book intended primarily for the biologist inexperienced in this work, and for sanitary engineers, chemists, and water pollution control administrators. The characteristics of aquatic environments, their biota, and the effects of various pollutants upon them are discussed and illustrated by examples of field investigations involving organic wastes, silts, toxic wastes, mine drainages, eutrophication, and radioactive wastes. Separate chapters describe the biology of water supplies and sewage treatment. The nature and control of biological nuisances such as slimes are discussed. Bibliography. (Author/AL)