engleski

Trace metals (Cd, Pb, Cu, Zn and Ni) in sediment of the submarine pit Dragon ear (Soline Bay, Rogoznica, Croatia)

The pit represents natural trap for all kind of particles enabling historical interpretation of trace metal influence on marine environment. Vertical profiles of trace metal (Cd, Pb, Zn, Cu, Ni) concentrations, organic matter content, carbonate content and granulometric composition were determined in two sediment cores from the submarine pit Dragon Ear. Higher concentrations of trace metals were determined in fine-grained sediment. Mean concentrations of analyzed metals (Cd: 0.06-0.12 mg kg-1, Pb: 28.5-67.3 mg kg-1, Zn: 17.0-65.4 mg kg-1, Cu: 21.1-51.9 mg kg-1, Ni: 27.8-40.2 mg kg-1) were in range usual for unpolluted carbonate marine sediments. Nevertheless, concentrations of Cu, Zn, and especially Pb in the upper layer of sediments (top 12 cm) reflected anthropogenic influence. Principal Component Analysis and the regression analysis were used to interpret the variations of trace metals, organic matter and carbonate content with depth, and to separate metals according to origin. Results of analysis indicated that, according to origin, Cd and Ni are derived primarily from natural sources, Pb originates primarily from human activities, while Cu and Zn originate from both natural and anthropogenic sources. Obtained results indicated that, except for lead which was enriched in surface sediment, in the time of sampling (before the building of the nautical marina) investigated area belonged to unpolluted areas.

Croatia; organic matter; sediment; submarine pit; trace metals

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