Kornati National Park is considered an environment with a minimal anthropogenic input. The purpose of my thesis was to determine the geochemical, mineralogical and isotopic characteristics of the sediment and muscle tissue of banded dye murex Hexaplex trunculus (Linne, 1758). The locations were selected according to the expected estimated large (Piškera in Vrulje), lower (Lojena in Mana) and minimum (Klobučar) possibility of anthropogenic pollution. Geological outskirts of selected locations represent Cretaceous limestones and dolomites, as well as Quaternary deposits of terra rossa at Vrulje.
Completed method of XRD indicated that carbonate minerals such as calcite, aragonite and dolomite, prevail in recent marine sediments at the selected locations. Quartz and other terrigenous silicates occur in a few more percentages at location Vrulje.
With the use X-Ray Fluorescence (XRF) and Inductively coupled plasma mass spectrometry (ICP-MS) we were able to determine the concentrations of main and trace elements, as well as the concentrations of potentially toxic elements (PTE) in the sediment. Higher PTE content is associated with a higher content of feldspars and terrestrial silicates at individual locations. PTE concentrations do not exceed the limit imission values for soil in Slovenia and Croatia, as well as the Probable effect level (PEL) and Threshold effect level (TEL). We calculated the level of pollution, enrichment factor (EF) and geoaccumulation index (IGEO) for certain PTE depending on the particular locations. At Vrulje there were slightly higher factors calculated for Cr, Cu and Zn, as a result of the use of fertilizers, pesticides and chemical assets to prevent corrosion.
Isotopic measurements of the sediment have shown, that the values of isotopic composition of organic carbon (δ13CORG) at Piškera (‒17,84 ‰) and Vrulje (‒18,50 ‰) were slightly elevated as compared to other locations, which may be the result of sea grass Posidonia oceanica in the sediment or the influx of terrestrial organic matter from the land.
Concentrations δ13CORG and δ15N in muscle tissue are the most positive at Piškera (‒14,47 ‰, +8,87 ‰) and Vrulje (‒15,66 ‰, +10,4 ‰), which indicate the presence of pigment indirubin (C16H10O2N2) which causes the purple colour, and the fact that the organisms are predators. The elevated content of δ15N could also be due to untreated sewage from a nearby marina and village.