Concentration of some elements in the Adriatic coastal sea sediments. Case study: the Kvarner Bay†

The analyses of 15 chemical elements in 70 surface sediment samples along the coast of the Kvamer Bay and its islands were carried out on the grain fractions < 2 mm by using the energy-dispersive x-ray fluorescence (EDXRF) analysis. The range of the measured elemental concentrations in mg/kg were: K (1121-14240), Ca (7200-261600), Ti (81-4178), Cr (6-169), Mn (17-534), Fe (310-34800), Ni (6-212), Cu (5-12640), Zn (12-11860), As (1.1-524.4), Br (14-373), Rb (2-151), Sr (112-1815), Y (8-80) and Pb (3-1430). The sediment concentrations of the biocidal elements Cu, Zn, As and Pb, usual components of available commercial antifouling paints, were found to be several orders of magnitude greater than the background values in sediments close to the marina or shipyard service areas. Contour maps of concentrations in the surface sediment layer for these four elements were produced, indicating the level and range of sediment contamination from the pollution sources. Factor analysis (FA) applied to the Kvarner Bay dataset has confirmed that among the measured elements, Cu, Zn, As and Pb contribute to the anthropogenic factor and the others to the two natural background factors. In order to investigate the negative environmental influence of marinas, shipyards and ports in more detail, the distributions of the element concentrations in the core and surface sediment samples were studied on a small geographical scale with the example of the Punat Bay and its shipyard, determined as contaminated zones in the Kvamer Bay. It was proved that the anthropogenic loads of the elements Cu, Zn and Pb from the local marina and the shipyard are the main sources of the bay pollution. Protection and remediation measures for the Croatian marinas, shipyards and small harbors could be proposed on the basis of these results.