This study presents a comprehensive investigation of the geochemical baseline values and the spatial distribution of major, trace elements, and rare earth elements in the unpolluted soils of Sicily region. The concentrations of elements were quantified by ICP-OES and ICP-MS. The distribution patterns of major and trace elements are closely linked to the geological features of the area. The major elements Fe, Ca, Al, Mg, and K exhibit the highest concentrations. The order of abundance for trace elements follows this trend: Ba, Sr, Zn, V, Cr, Cu, Rb, Ni, Pb, B, Li, Co, As, Mo, U, Sb, Se, Cd, and Bi. Regional geochemical baseline values were calculated using the UTL95 - 95 method with BCA bootstrap, demonstrating that the regional approach provides a more accurate assessment compared to European and Italian threshold values. A geostatistical approach was used to produce spatial geochemical maps, which allow the prediction of element distributions in unsampled areas. This integrated approach establishes a benchmark for more detailed studies on environmental risk assessment, providing a solid foundation for identifying and understanding natural and anthropogenic geochemical anomalies in the soils of the Sicily region.

Chemical weathering is the main natural mechanism limiting the atmospheric carbon dioxide levels on geologic time scales (>1 Ma) but its role on shorter time scales is still debated, highlighting the need for an increase of knowledge about the relationships between chemical weathering and atmospheric CO₂ consumption. A reliable approach to study the weathering reactions is the quantification of the mass fluxes in and out of mono lithology watershed systems. In this work the chemical weathering and atmospheric carbon dioxide consumption of ultramafic rocks have been studied through a detailed geochemical mass balance of three watershed systems located in the metaophiolitic complex of the Voltri Massif (Italy). Results show that the rates of carbon dioxide consumption of the study area (weighted average = 3.02 ± 1.67 × 10⁵ mol km⁻² y⁻¹) are higher than the world average CO₂ consumption rate and are well correlated with runoff, probably the stronger weathering controlling factor. Computed values are very close to the global average of basic and ultrabasic magmatic rocks, suggesting that Voltri Massif is a good proxy for the study of the feedbacks between chemical weathering, CO₂ consumption, and climate change at a global scale.

Dissolved and suspended toxic elements in water discharged from abandoned and active mining areas pose several critical issues, since they represent a threat to the environment. In this work, we investigated the water, suspended particulates, and stream sediments of a 2.1 km long creek (Fosso della Chiusa) that is fed by waters draining the galleries of the abandoned Hg mining area of Abbadia San Salvatore (Mt. Amiata, Tuscany, central Italy). The geochemical results show evidence that the studied matrices are characterized by relatively high concentrations of Hg and As, whereas those of Sb are generally close to or below the instrumental detection limit. Independent of the matrices, the concentration of As decreases from the emergence point to the confluence with the Pagliola creek. In contrast, Hg concentrations display more complex behavior, as water and sediment are mainly characterized by concentrations that significantly increase along the water course. According to the geoaccumulation index (I_geo), sediments belong to Class 6 (extremely contaminated) for Hg. The I_geo of As varies from Class 6, close to the emergence, to Class 2 (moderately contaminated), dropping to Class 0 (uncontaminated) at the confluence with the Pagliola creek. Finally, the total mass load of Hg and As entering the Pagliola creek was computed to be 1.3 and 0.5 kg/year, respectively, when a mean flow rate of 40 L/s was considered. The calculated loads are relatively low, but, when the Fosso della Chiusa drainage basin is taken into account, the specific load is comparable to, or even higher than, those of other mining areas.

Ab-initio thermophysical properties and isotopic separative effects in MgCr₂O₄ were computed with the CRYSTAL03 code. All calculations were carried out within the LCAO approach (Linear Combination of Atomic Orbitals) by using the Hartree-Fock and the hybrid B3LYP density functional methods. Vibrational frequencies have been computed at the long-wavelength limit corresponding to the center of the Brillouin zone (k → 0). Since thermodynamic functions depend on the phonon dispersion relation, the ab-initio based vibrational analysis of the optical modes has been coupled with the semiempirical Kieffer model for the acoustic modes, which is based on a sine wave dispersion equation. All computed magnitudes (zero point energy, internal energy, Helmholtz free energy, optical vibrational modes, thermal corrections to internal energy, enthalpy and Gibbs free energy, thermal pressure, bulk modulus and its P and T derivatives, entropy, isochoric and isobaric heat capacity, and isotopic separative effects) are consistent with direct observations and/or reasonable estimates, within the accuracy of the method. The computed separative effects are similar to those observed in other Cr³⁺-bearing substances. The crystal field seems to have no influence on the separative effect for an isotopomeric couple with respect to an isolated gaseous couple with Cr³⁺ as central cation.