Pollution mechanisms in a Ramsar wetland: delta of the River Evros, Greece

The pollution mechanisms affecting the protected wetland of the river Evros delta, were investigated during an one year survey (1992-1993). The eastern part of the wetland was mainly influenced by river transported pollution which is generated in the greater catchment basin of the river Evros, in Bulgaria, Turkey and Greece. In this part of the wetland, the highest concentrations of organic matter were found during summer, but nutrients concentrations increased during the early winter months. Nitrogen concentrations remained high throughout spring but SRP concentrations decreased considerably during the same period. In the western part of the wetland, the watercourses were mainly influenced by local activities (agriculture and animal breeding) but pollutant concentrations were lower than in the river stations. These preliminary results indicate that river transported pollution is the major factor for the quality degradation of the wetland's waters.