Potentially toxic elements in ultramafic rocks and soils: A case study from the Voltri Massif (NW Italy)

openHigh concentrations of potentially toxic elements (PTEs) in surface and near-surface environment may be attributed to both anthropogenic sources, including industrial and agricultural activity, and geogenic source, mainly due to natural weathering of rocks. Considering the geogenic sources, ultramafic rocks (e.g., dunite, peridotite, pyroxenite, and serpentinites) are among the most critical from the environmental point of view; in fact, they are characterized by high contents of Cr, Ni, Co, and other PTEs which can have potential harmful impact on ecosystems and human health if released into soils and waters during weathering and pedogenic processes. As a matter of the fact, weathering of ultramafic rock produces ultramafic soil containing high concentration of PTEs, including Cr, Ni, and Co compared to soils derived from non-ultramafic bedrock. Although ultramafic rocks and relative soils cover approximately 1% of the Earth’s surface, they are distributed worldwide and are commonly associated with ophiolite complexes; for this reason, they play an important role in environmental management. The main objective of this PhD thesis was to determinate the mineralogy and the chemistry of PTEs of ultramafic soil profiles from the Voltri Massif and to evaluate how lithological, textural, and structural properties of the ultramafic bedrock with various degree of serpentinization and deformation may affect the PTEs re-distribution and the fate in the soils during pedogenesis, as well as to assess their environmental implications in the ecosystem. The multidisciplinary and multiscale approach, used in this PhD thesis, has allowed to highlight a series of considerations that led to the following conclusions: • In the studied rocks, Cr, Ni, and, subordinately, Co are invariably the PTEs with the highest concentrations; in addition, V, Cu, and Zn are generally found in high concentrations. The main factors controlling the PTEs distribution within the studied ultramafic rocks appeared to be the serpentinization degree and the deformation style and intensity. The main source of the PTEs are spinel-group minerals. Moreover, PTEs-bearing phases are also represented by the other rock-forming minerals (such as serpentines, olivines, pyroxenes, and chlorites) and some accessory phases (e.g., ilmenite and other oxides, sulfides). • The studied ultramafic soil profiles vary in thickness from 35 to 80 cm and are characterized by weakly developed A and C horizons and a very thin O horizon (up to 5-10 cm). In general, in the soils the mineralogy of the skeleton (sandy and silty fractions) is closely related to bedrock mineralogy as expected for primitive A-C soils (in order of abundance: antigorite, chlorite, spinel-group minerals, pyroxenes, authigenic phases, quartz, olivine, and tremolite). The clay fraction is mainly composed by amorphous or low-crystalline Fe-oxyhydroxides, serpentines, smectite and illite/smectite mixed-layer clay, and clinochlore. Cr and Ni values have very variable concentrations over a wide range. Cr and Ni decrease according to serpentinization degree of bedrock. Co, Zn, and Cu do not show a clear correlation with bedrock serpentinization. V increase with the serpentinization of the bedrock. The PTEs concentrations in the studied ultramafic soil profiles are linked both to the primary minerals, inherited by bedrocks (e.g., serpentines, spinel-group minerals, pyroxenes, chlorites), and to their stable authigenic products (Fe-oxyhydroxides and clay minerals). The PTEs leached from the primary minerals is mainly scavenge by goethite, and subordinate by clay. • The results evidence that Cr, Ni, and, Co systematically exceed (up to one order of magnitude) the residential and industrial threshold values (CSC) according to Italian law (D.M. 471/1999; D.Lgs 152/2006) both in rocks and soils. However, combining all my results, I have demonstrated that the critical PTEs concentrations in the studied profiles have a geogenic origin and are linked both to the primary minerals, inherited by bedrocks, and to their stable authigenic products. Considering the high stability of authigenic products in supergenic environment, it is evident that this mineral species are effective and often permanent traps for the most important PTEs of ultramafic soils and bedrocks, thus reducing its bioavailability. A study of this kind that combine the bulk chemistry of outcropping rocks and the relative soil profiles with their geological, structural, mineralogical, and crystallochemical data, can be also a useful tool in environmental concerns to determine the PTEs distribution, to evaluate their potential mobility and bioavailability as well as to discriminate the natural geochemical background from possible source of contamination.openXXXI CICLO - SCIENZE E TECNOLOGIE PER L'AMBIENTE E IL TERRITORIO (STAT) - Scienze della terraCOMODI, PAOLA (Università di Perugia)Fornasaro, Silvi

Sers-based nanosensors for the sensitive detection of reactive oxygen species

The unbalanced production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been implicated in the pathogenesis of several human diseases. Indeed, there is great interest in developing methods for measuring quantitatively and selectively the production of ROS/RNS in living cells. Here, we report a simple and sensitive method for the detection of ROS, based on surface-enhanced Raman scattering (SERS) spectroscopy

Meccanica Lagrangiana Relativistica

La presente tesi ha lo scopo di sfruttare gli strumenti propri della meccanica analitica per dedurre alcuni risultati di notevole importanza nella teoria della relatività ristretta sviluppata da Albert Einstein nel 1905. In particolare verrà utilizzata la metrica dello spaziotempo per ricavare la funzione Lagrangiana, e attraverso le equazioni di Eulero-Lagrange si studierà l'equazione del moto di una particella libera e, successivamente, soggetta a un campo elettromagnetico

Targeting natural antioxidant compounds to the brain: a metabolomic assessment

2013/2014A diet rich in fruits and vegetables has been associated with a decreased risk of brain diseases. Some plant-specific compounds occurring in fruits and vegetables, such as flavonoids, have been found to exert neuroprotection, thus decreasing neurological disease risk. The current hypothesis is that neuroprotection is due to the antioxidant properties of flavonoids. The main aims of this PhD thesis were: i) to assess whether some flavonoids are transported from the blood into the brain across the blood-brain barrier, ii) to understand if neuroprotection is mediated by an impact on brain metabolism. The first part of the thesis describes in vivo experiments with cyanidin 3-glucoside (C3G), implementing different metabolomics analyses approaches. Mean Time (MT) parameters are reported as useful indicators of the retention properties of C3G in peripheral tissues. The second part deals with the development and characterisation of a selective and sensitive analytical method, based on Surface-Enhanced Raman Spectroscopy (SERS), enabling the assessment of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in living cells.Una dieta ricca in frutta e verdura è stata associata a un ridotto rischio di malattie neurodegenerative, e alcuni composti antiossidanti presenti in frutta e verdura, come i flavonoidi, sono stati riconosciuti come agenti neuroprotettivi. Gli obiettivi principali dell’attività di ricerca riportata in questa tesi sono stati la valutazione del passaggio dal sangue al cervello, attraverso la barriera emato-encefalica, di alcuni flavonoidi, la comprensione del loro impatto sul metabolismo del cervello e del loro meccanismo d'azione come agenti neuroprotettivi. La prima parte della tesi descrive diversi approcci di analisi metabolomica utilizzati in esperimenti in vivo con cianidina 3-glucoside (C3G). Parametri di tempo medio sono riportati come utili indicatori delle proprietà di ritenzione di C3G nei tessuti periferici. La seconda parte presenta lo sviluppo e la caratterizzazione di un metodo analitico, basato sulla spettroscopia Raman amplificata da superfici (SERS), per la determinazione di specie reattive dell’ossigeno e dell’azoto (ROS/RNS), in cellule viventi.XXVII Ciclo198

Primary and authigenic minerals in serpentine soils under temperate climate conditions: source or trap for potentially toxic elements (PTEs)

In this study, we have analysed the mineralogy and the crystal chemistry of serpentine soils from ultramafic rocks of the metaophiolitic Voltri Massif (Liguria, Italy), in order to determine the primary and authigenic mineral species controlling the distribution and the mobility of PTEs during pedogenic processes. These serpentine soils were characterised by PTEs contents commonly exceeding the concentration limits laid down by environmental agencies, particularly for Cr (1200-2500 mg/kg) and Ni (1000-4200 mg/kg). With these hazardous PTEs concentrations, the knowledge of the distribution of PTEs-bearing minerals is of paramount importance for understanding their origin and their fate during the development of serpentine soil profiles and can allow to evaluate their effective bioavailability. All the studied soil profiles were restricted in depth (10-50 cm) and showed a low degree of maturity with weakly developed A-C horizons. Soil samples were subdivided into three aliquots in order to separate the soil skeleton (2 mm-63 \u3bc m) from the silt (63-2 \u3bc m) and clay fraction (<2 \u3bc m). Quantitative mineralogical analyses were performed in all aliquots by using XRPD data collected with synchrotron sources at the MCX beamline (ELETTRA - Synchrotron, Trieste, Italy) and refined with EXP-GUI GSAS software. Trace metals were determined with energy and wavelength electron microscopy. The mineralogy of the coarse and silty fractions was closely related to bedrock mineralogy. The following minerals were detected in decreasing order of abundance: antigorite, chlorite, tremolite, magnetite, Cr-rich spinel, chrysotile, ilmenite, clinopyroxenes, olivine. Allochthonous quartz and albite were always present as minor to trace constituents. The clay fraction was mainly composed by Fe-oxides and -oxyhydroxides (mainly hematite and goethite) with subordinate amounts of mixed-layer clay minerals (chlorite-smectite, chlorite-vermiculite). These authigenic secondary minerals were characterised by poor crystallinity, intimate intergrowths, and fine-scale heterogeneities. PTEs were hosted mainly in the residual primary minerals deriving from the underlying parent material and subordinately in secondary authigenic phases. Cr was mainly contained within spinels (magnetite, Cr-magnetite, ferrichromite, picotite, and hercynite), antigorite, diopside and augite. Nonnegligible amounts of Cr was also present in authigenic hematite (up to 0.1 wt%) and goethite (up to 0.15 wt%). The main Ni-bearing minerals were olivine and antigorite but significant Ni concentration was also detected in authigenic hematite (up to 2.8 wt%) and goethite (up to 4.2 wt%) which thus represented effective traps for Ni leached through mineral weathering to the soils solution. These results are the preliminary step for the evaluation of the role of mineral species in controlling the PTEs mobility during the evolution of serpentine soil profiles. Quantitative mineralogical data will be further used to perform mass balance calculations as well as to interpret and model the results of batch leaching experiments that will be conducted on the different soil fractions

Potentially Toxic Elements in Ultramafic Soils: A Study from Metamorphic Ophiolites of the Voltri Massif (Western Alps, Italy)

Ultramafic soils are characterized by severe edaphic conditions induced by a low content of essential nutrients, an adverse Ca/Mg ratio, a low water-holding capacity, and high contents of geogenic potentially toxic elements (PTEs), in particular Cr, Ni, and Co. These metals commonly exceed the content limits set by environmental agencies and governments, representing serious environmental risks for ecosystems and human health. In alpine environments, ultramafic soils are characterized by modest thickness and poor horizon differentiation. Several studies on ultramafic soils have shown that their properties may be directly related to the characteristics of the parent rocks, but most of these studies deal with soil chemistry, metal availability, isotopic composition, and pedological characterization. The aim of this research is to investigate how much the geotectonic characteristics of ultramafic bedrocks, such as the degree of serpentinization, metamorphic imprint, and deformation, may affect the mineralogical and chemical variations of ultramafic soils, including the occurrence and potential mobility of the PTEs. Using a multiscale and multi-analytical approach, we fully characterize the properties and mineralogical composition of soil profiles with different ultramafic parent rocks, i.e., partially serpentinized peridotite, massive serpentinites, and foliated serpentinites, sampled within the Voltri Massif High Pressure\u2013 Low Temperature (HP\u2013LT) metaophiolite (Western Alps, Italy). Our results, related to soils located at comparable latitude, altitude, landscape position, and pedological environment, outline that the degree of serpentinization, the metamorphic imprint, and the deformation history of the ultramafic parent rocks are key factors influencing soil evolution, mineralogy, and chemistry, as well as PTEs distribution and mobility. Moreover, this study shows that the high content of Cr, Ni, and Co in the studied ultramafic soils has to be considered of geogenic origin and highlights the need for new approaches and methods to obtain indications on the potential contamination of natural or anthropogenic soils

On the possibility of low cost, adherent therapeutic drug monitoring in oncology

A frequent quantification of drugs concentrations in plasma of patients subject to chemotherapy is seldom performed, mostly because the standard methods (Gas or Liquid Chromatography coupled with Mass Spectroscopy) are expensive and time consuming. In this paper we report the approach pursued in one of the research units of the EU project RAMAN4CLINICS to tackle the problem of a low cost, time adherent quantification of drugs used for oncological patients using a Surface Enhanced Raman Scattering (SERS) spectroscopy. More specifically, the issues concerning the repeatability of the nanostructured substrates will be presented and some promising results to increase the selectivity of the measures toward specific drugs will be discussed, with examples concerning one cytotoxic agent, Irinotecan and one kinase inhibitor, Sunitinib

Potentially toxic elements distribution in the serpentinized and deformed ultramafic rocks from the Voltri Massif (NW, Italy)

The aim of the work is to assess the role of local-scale lithological, textural, and structural factors in the distribution of potentially toxic elements (PTEs) in different ultramafic rocks from the high-pressure ophiolitic Voltri Massif (Central Liguria, NW Italy). The results evidenced that Cr (up to 4183 ppm), Ni (up to 3900 ppm), and Co (up to 334 ppm) are invariably the PTEs with the highest concentrations; in addition, V, Cu, and Zn are systematically found in non-negligible amounts. Spinel-group minerals (chromium spinel, ferrian chromite, chromium magnetite, and magnetite) are by far the main potential source of the PTEs. Nevertheless, several PTEs are also present within serpentines, olivines, pyroxenes, chlorites, as well as within accessory phases (e.g., ilmenite and Ni-sulphides) and within authigenic minerals formed in the early stages of rock weathering (cryptocrystalline to amorphous Fe-oxides and -oxyhydroxides). The result obtained allowed to evidence that the main factors controlling the PTEs distribution within the rocks resulted to be the serpentinization degree and the deformation style and intensity which, in turn, strictly control the mineral assemblages and the mineral chemistry

Physical, Biochemical and Biological Characterization of Two Opposite Areas in the Southern Adriatic Sea (Mediterranean Sea)

The Drini and Manfredonia Gulfs were investigated in May 2008 and April 2009, respectively. The gulfs are located in the South Eastern (Gulf of Drini) and South Western (Gulf of Manfredonia) Adriatic Sea. The areas are partially influ- enced by two main Adriatic surface currents: the Eastern Adriatic Current-EAC that flows north-westward along the eastern side, and the Western Adriatic Current-WAC that flows south-eastward along the western side of the basin. The spatial variations of temperature, salinity, fluorescence, dissolved oxygen concentration, Coloured Dissolved Or- ganic Matter-CDOM, nutrients, chlorophyll a and phytoplankton composition parameters in the two areas were ob- served and compared. CDOM regulates the penetration of UV light into the sea and plays an important role in many hydrological and biogeochemical processes on the sea surface layer including primary productivity. The phytoplankton specific diversity of the Gulf of Manfredonia showed a spring community with dinoflagellates (21 taxa) as the main important fraction, coccolithophorales (6 taxa) and diatoms with 10 identified taxa. The phytoplankton distribution along the eastern coast showed a different biodiversity: a prevalence of dinoflagellates (58 taxa) included harmful mi- croalgae such as Alexandrium, Dinophysis and Lingulodinium genus. Diatoms were less abundant, among them Pseudo-nitzschia was also reported which could include some potentially toxic species. Nanoplankton are ever abun- dant in offshore waters and an exceptional bloom of cyanobacteria was registered in Buna-Boyana estuary due to strong industrial impact. The gulfs showed similar physical and biochemical characteristics despite the WAC carried out along the western Adriatic Sea the water rich in nutrients from the major northern Italian rivers. No correlations were found between CDOM and chlorophyll a in the two areas and this implied that, probably, the primary source of CDOM might come from terrestrial input rather than the biological production from phytoplankton. The Gulf of Drini is impacted by the runoff of the Buna-Bojana River that makes this gulf an eutrophic area despite the mostly eastern side of the Adri- atic being an oligotrophic basin