Relationships between radionuclides, metals, and sediment properties in sediment of a bay exposed to anthropogenic pressure and mixed sediment sources (Kaštela Bay, Adriatic Sea, Croatia)

Abstract

Natural and anthropogenic radionuclides, metals, organic matter, sediment grain size, mineral composition, and sediment sources were studied in marine sediment of Kaštela Bay up to a depth of 0.5 m. Deposition of man-modified material into the sea was evidenced in sediment mineral composition. Presence of pyrite and hematite in this sediment may pose an environmental concern. Metals, radionuclides, and organic matter were grouped in three groups: (i) variables under no anthropogenic influence and preferentially associated with carbonates (Ca, Sr); (ii) variables under no or weak anthropogenic influence and preferentially associated with aluminosilicates (Al, K, Ti, V, Cr, Mn, Fe, Co, Ni, Ga, Rb, Y, ⁴⁰K, ²³²Th); (iii) variables under notable anthropogenic influence and/or natural processes of separation (Cu, Zn, Pb, As, ²²⁶Ra, ²³⁸U, ¹³⁷Cs, organic matter). Predominant influencing parameters change with sediment depth for some variables. Anthropogenic influence was the most emphasised for Cu, Zn, and Pb, followed by ¹³⁷Cs.

Keywords: Coastal zone; Flysch; Karst; Marine sediment; PCA; Radioactivity.