Assessment of Water Quality as a Key Component in the Water–Energy–Food Nexus

The intensive economic activity along the Bulgarian Black Sea coast is causing serious changes in the quality of the river water. In view of the topicality of the problem, the main goal of this article is to emphasize the water quality as a necessary key component in the water–energy–food nexus by determining the status of the surface waters of selected Bulgarian Black Sea tributaries from the point of view of their physicochemical characteristics. The research is based on the Water Framework Directive (WFD)—2000/60/EU and the relevant national legislation. In the present study, the Canadian Complex Water Quality Index (CCME, WQI) was applied to determine the quality of river waters. The novelty in the present study is a definite and necessary emphasis on the opinion that the analysis and assessment of water quality should become an integral part of all studies of the water–energy–food nexus.