Baseline levels of trace elements in coastal sediments from the central Mediterranean (Tuscany, Italy)

The aim of this paper was to define for the coastal areas of Tuscany (Central Tyrrhenian Sea) relationships between certain trace elements (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, V, and Zn) and others (Al, Ba, Cs, Fe, Li, and Rb) proposed by the literature as useful tracers for natural background levels due to aluminosilicates. Relationships among trace elements and sediment descriptors (pH; oxidative-state (Eh); total inorganic carbon; grain-size; and nutrients, total carbon (TC), total nitrogen (TN), total phosphorous (TP), and organic matter (OM)) were also explored. Some sediment descriptors (pH, Eh, TC, TN, TP, and OM) were strongly auto-correlated. To the best of our knowledge for Cs (<0.01 mg kg−1), Li (38.75, 5.20–80.89 mg kg−1), Rb (39.74, 1.88–197.10 mg kg−1), and V (39.03, 7.84–95.23 mg kg−1), this was the first time that levels were defined in sediments from this geographical area. Results reported in this study evidenced that, among the considered trace elements, Ba and Rb represent useful tools for sediment management purposes and for risk assessment evaluations associated with sediment dredging in harbours and trace-element-polluted sites along the Tuscan coast.