The use of various methods for the study of metal pollution in marine sediments, the case of Euvoikos Gulf, Greece

This study presents the results on heavy metal (Mn, Fe, Cu, Zn) analyses of sediments taken from Euvoikos Gulf, Greece, which is a semi-enclosed system receiving pollution loads from several urban and industrial sources and is affected by a strong tidal current. A sequential extraction schema and two single-step methods were used for the determination of trace metals. The data of the 1997 period are compared with data from previous studies carried out in the authorsʹ laboratory in the area (1980, 1993) using various analytical techniques, in an attempt to evaluate both the evolution of pollution in the area and the effectiveness of analytical methods. It has been confirmed that a significant part of the pollution load remains in coastal localities in the vicinity of the land based pollution sources, whereas there are also some more remote sites where small polluted particles are transported, deposited and accumulated. The sedimentology regime of the area affects the concentration of metals in a rather complex way depending also on its content of carbonates, organic C and clay minerals. The study of sediment cores has indicated elevated metal concentrations in recent surface sediments. On the other hand, some environmentally positive trends were also observed (i.e. the reduction of mobile metals). A systematic monitoring is needed in the marine environment coupled with some reduction in pollution inputs and integrated management on the coastal zone because the overall hydrological characteristics of the area favour its rapid self-restoration.