Occurrence and Distribution of Technology-critical Elements (TCE) in Recent Freshwater and Marine Pristine Lake Sediments in Croatia: a Case Study

Abstract

The appearance and vertical distribution of technology-critical elements (TCE) such as Li, Nb, Sc, Ga, Y, La, Sb, Ge, Te, and W were investigated in sediment cores taken in pristine freshwater and marine lakes located within protected areas of Croatia (Plitvice Lakes, Visovac Lake, and Mir Lake). These lake systems are isolated from the direct impact of human activities, and accordingly, the geochemical research in such environments may help to assess temporal trends in historical deposition of anthropogenic TCE. The analytical method of choice in determining the concentration of TCEs was High resolution inductively coupled plasma - mass spectrometry (HR ICP-MS). The results obtained have shown that the measured TCE spanned with wide ranges of concentrations, as a result of the different input of terrigenous material into the investigated lake systems which is further diluted by the formation of authigenic and biogenic carbonates. Evaluation of the anthropogenic impact on TCE levels showed low enrichment of Sb and Te in the upper sediment layers of the Mir Lake and the Plitvice Lakes. Despite that, concentrations of investigated TCE were low, compared to results described in the literature, indicating that the investigated remote lakes can be considered uncontaminated with these elements.