Natural and anthropogenic effects on the sediment geochemistry of Nestos river, Northern Greece

Fourteen sediment samples from the banks of river Nestos, Northern Greece, were collected, extracted with HNO3 and analyzed for their content in 10 major and 32 trace elements. The analytical methods used were ICP-OES and ICP-MS. The results indicate that the sediments in the northern Greek part of the river have the highest elemental concentrations partly because of human activities, but mainly due to natural processes. The two dams that have been constructed in the middle course play a buffering role on the elemental content, for all the elements analyzed, of the river sediments, decreasing downstream concentrations and sediment load. An increase of concentrations is newly observed in the low course and delta because of the mobilization of fine sediments by natural processes and agricultural practices. The comparison of the river sediment contents with contaminated land guidelines has not revealed any potentially dangerous concentrations for the elements analyzed.