With its 104 chapters, this Encyclopedia reveals the diversity of issues, problems and challenges that faced, and are facing today, receiving environments. It also indicates ways by which tools, strategies and future investigations can contribute to correct, minimize, solve and prevent water quality degradation. Structured homogeneously, the chapters convey salient information on historical background, features, characteristics, uses and/or applications of treated topics, often complemented by illustrations and case studies, as well as by conclusions and prospects.