Trace metals conservation in Morinje Bay sediment: Historical record of anthropogenic imissions into a shallow Adriatic Bay

Geochemical and sedimentological characteristics, the sediment accumulation rate (by Cs-137 dating) and vertical distribution of trace metals (Pb, Cu, Zn) in sediments from Morinje Bay (Central Dalmatia-Croatia) have been studied. The sediment is fine-grained, well-sorted silt throughout the investigated section. The very high average sedimentation rate (4.5 cm in 3 years, or 1.65 g dry sediment/cm(2) per year) in Morinje Bay, compared to the nearby coastal areas of the Rogoznica lake and the Krka river estuary, may be a result of high aeolian supply of material from the agricultural field of Donje polje, and influenced by the seasonal input from the rapid streamlet Ribnik draining the surrounding area. Concentrations of most trace metals in the Morinje Bay sediments are in the range typical of unpolluted marine carbonates. However, concentrations of Pb, Cu and Zn, in recent and subrecent (down to 50 years before the present) sediments reflect anthropogenic influences. Leaded gasoline seems to be the principal anthropogenic source of Pb enrichment, while Zn and Cu may be of urban and agricultural origin