Estuaries in every country exemplify the same paradox — they are among the most productive ecosystems and also among the most impacted by anthropogenic activities. And although estuarine biodiversity is key to the ecological and economic health of coastal regions, estuaries are exposed to toxic effluents transported by rivers from remote and nearby conurbations and industrial and agricultural concerns, putting them at risk. Increased attention to environmental issues highlights the fragility and importance of estuaries and brings to the forefront the need for an up-to-date assessment of techniques.choses…