This book discusses various freshwater ecosystems and methods used for the purposes of water quality monitoring, including those utilising aquatic macrophytes. Early-established management plans provide the first steps towards sustainable management of aquatic environments. Thus, the methods used for managing aquatic plants, including mechanical or manual harvesting, hand-pulling and biological control are discussed. The removal efficiency of nutrients and of metal by macrophytes is examined, as well as the potential use of these plants in wastewater treatment. This book surveys and critically reviews existing literature regarding the presence of steroid sex hormones in freshwater ecosystems, their sources and potential fate. Discharges from wastewater treatment plants and transport from agricultural operations are also examined. Finally, this book discusses the role of NF-kB inhibitors, an inducible transcription, in marine chemical ecology, as well as its role in biomedicine.