La completa caratterizzazione elementare di campioni ambientali e agroalimentari è un punto chiave nella ricerca scientifica e nel controllo di qualità. In questo contesto, l'uso di metodologie analitiche che impiegano raggi X consente di analizzare diverse tipologie di campioni riducendone al minimo la preparazione ed evitando, così, la perdita o la contaminazione dei campioni, come spesso accade a seguito di processi condotti in umido. Inoltre, queste metodologie consentono di ridurre i tempi e i costi di analisi, nonché di limitare l‟uso di prodotti chimici. Presso l'Università di Bari è stato di recente realizzato il "Micro X-ray Lab", un laboratorio all'avanguardia internazionale, dotato di strumenti che impiegano raggi X al fine di caratterizzare campioni ambientali, agroalimentari e biologici. Il laboratorio, finanziato dalla Regione Puglia (Reti di Laboratori Pubblici di Ricerca), è dotato di quattro diversi spettrometri di fluorescenza di raggi X, un diffrattometro di raggi X per polveri, un microscopio elettronico a scansione a pressione variabile con sorgente ad emissione di campo e detector di raggi X a dispersione di energia e un microtomografo ad alta risoluzione. Una prima analisi speditiva in situ, viene effettuata con la fluorescenza di raggi X portatile (pEDXRF). In seguito, la concentrazione totale dei vari elementi viene stimata con maggior precisione in laboratorio mediante la fluorescenza di raggi X a dispersione di lunghezza d'onda (WDXRF). Nel caso di suoli, sedimenti e materiali geologici è inoltre possibile studiare la loro composizione mineralogica mediante la diffrazione di raggi X su polveri (XRPD). Per mezzo della micro fluorescenza di raggi X (μXRF) è possibile studiare la distribuzione degli elementi in campioni biologici o inorganici con una risoluzione spaziale di 25 μm. Per campioni più piccoli o per avere una maggiore risoluzione (fino a poche decine di nanometri), è possibile impiegare il microscopio elettronico accoppiato alla microanalisi (FESEM-EDX). Mediante la fluorescenza di raggi X a riflessione totale (TXRF), è possibile stimare la concentrazione di elementi in tracce, a livello di ppb, in campioni sia liquidi che solidi (in sospensione). Questa tecnica consente anche di analizzare micro volumi (10-20 μl) di campione, come nel caso di fluidi biologici, sia animali che vegetali. Infine, attraverso la microtomografia (μCT) è possibile studiare la struttura interna dei campioni con una risoluzione submicrometrica.

Heavy metals (HM) in soils can be toxic for cultivated plants and living organisms and can pose a serious risk for human health, especially if they can reach underground waters or enter the food chain. Determining HM total concentration in soil is only the starting point of a risk assessment, but nowadays information about HM speciation is crucial to understand the real impact of HM pollutants on the environment. In addition, soil is an extremely heterogeneous matrix where different organic and inorganic components are mixed down to the micrometer or nanometer scale. Therefore analytical instruments capable of resolving such a complexity at the nanometer/micrometer scale are also needed. To this purpose, a proper combination of X-ray analyses can provide both information about HM total concentration and speciation also at the nanometer/micrometer level. At the University of Bari a new laboratory called "Micro X-ray Lab" has been created. In this lab, the potentialities of different X-ray based analytical techniques are combined to solve problems related to soil HM pollution and remediation. To this purpose the following instrumentation is available: a portable X-ray fluorescence spectrometer (pXRF) (for quick semiquantitative in situ analyses), a wavelength dispersive X-ray fluorescence spectrometer (WD-XRF) (for more precise determinations of HM in solid and liquid samples), a total reflection X-ray fluorescence spectrometer (TXRF) (for the determination of HM at ppb levels), a micro X-ray fluorescence spectrometer (µ-XRF) and a Variable Pressure Field Emission Scanning Electron Microscope (for the identification of HM pollutants at the micro/nano-scale). In addition, HM-containing mineral phases of soil samples are investigated by X-ray powder diffraction (XRPD) and thermogravimetrical and differential thermal analyses (TGA/DTA). Finally, X-ray microtomography (µ-CT) is used to characterize the soil structure, its porosity as well as the internal structure of microscopic soil minerals. The same methodological approach can be applied to the study of HM in other environmental materials such as plant and biological matrices and to assess the efficacy of technologies developed for the remediation of HM polluted soils. In this work, preliminary results on HM speciation and biaccessibility studies in polluted soils are presented and discussed with a focus on As-polluted soils. The aim of these studies are to identify the source and the fate of pollution as well as to develop suitable physical-chemical procedures to remediate the contaminated sites.

Clay minerals are phyllosilicates originating from the weathering of primary silicates and aluminosilicates. Due to their mineralogical and chemical characteristics they are largely employed in different fields such as chemical, pharmaceutical and food industry, ceramics production, crude oil extraction, etc. In order to assess the suitability of a certain clay material for a particular use, both mineralogical and chemical analyses are usually performed. In particular, for the elemental analysis of clays, standard procedures are based on WDXRF or ICP-OES analyses, which usually require 1-5 g of sample (UNI EN ISO 21587-3:2007, EN ISO 12677:2011). In addition, both the production of beads for WDXRF and the sample digestion for ICP-OES analyses need long and elaborate processing of samples, often requiring costly chemicals which can be also dangerous for the environment and the operator. Furthermore, in case of specific applications (e.g., clay micro-synthesis, bacteria-induced clay synthesis, remediation or sorption studies, etc.) the production of enough amount of sample is often a critical issue. In such cases, chemical analysis is usually performed with SEM-EDS which, besides requiring the use of a complex and expensive instrumentation, cannot provide information about the bulk sample composition. In the last two decades, total-reflection X-ray fluorescence spectroscopy (TXRF) has proven to be a sensitive and fast technique for the elemental analysis of several types of matrices (both organic and inorganic), requiring only a low amount of sample (few mg) and a simple sample preparation. In this work, a simple, fast and reliable method for the elemental analysis of clays employing TXRF is proposed. Clays are analysed by TXRF as suspensions deposited on sample carriers (reflectors). The method has been optimized using a two level full factorial design, using selenium as internal standard, to obtain the best recovery rate for each focused element. In particular, the following factors have been evaluated: sample amount, surfactant volume and reflector type. The best results were obtained by suspending 50 mg of clay in 2.50 ml of surfactant and using quartz reflectors for TXRF analyses. The optimized method has been subjected to in-house validation to evaluate analytical performances such as linearity, quantification limits, trueness and precision. The validation study included the analysis of certified reference materials (SARM-CRPG-CNRS). Satisfactory performances were obtained for most of the major elements including Mg, Al, Si, K, Ca, Ti, Mn and Fe and some minor elements (Cl, Ni, Zn, Ga, Rb, Sr and Pb).

Chromium (Cr) pollution of soil is a serious environmental problem, especially in industrialized areas. Risks for human and environmental health are strictly connected to Cr oxidation state, which is usually trivalent or hexavalent in soil. While Cr(III) is stable, scarcely mobile and weakly toxic, Cr(VI) is highly soluble, mobile and carcinogenic. Among the different remediation strategies, stabilization/solidification (S/S) is used as rapid and cost-effective technique for heavy metal polluted soils. It consists of the addition of appropriate materials to the polluted soil, mostly under alkaline conditions, in order to chemically and/or physically transform the contaminant in a stable and less toxic form. Waste materials like coal fly ash or other cheap sources of Si and Al can be used to stabilize heavy metals in soil (Terzano et al., 2005). This study aims at evaluating a new S/S process for the reduction of Cr(VI) to Cr(III) in polluted soils and the incorporation of Cr(III) in newly formed minerals by using a reactive mixture of glass and aluminum (recovered from solid municipal wastes) and an alkaline hydrothermal treatment.

L’indagine del suolo e delle forme di inquinamento in esso presenti, fino a livelli micrometrici, è uno strumento essenziale ai fini della comprensione delle cause di inquinamento e della definizione e realizzazione delle strategie di bonifica. In presenza di inquinamento da metalli pesanti (MP), non è sufficiente individuare gli elementi con concentrazioni superiori ai valori soglia di contaminazione stabiliti dalla legge, ma occorre altresì indagare la speciazione dei MP e la loro biodisponibilità. In questo studio, tecniche analitiche innovative che impiegano raggi-X e procedure convenzionali sono state utilizzate per caratterizzare alcuni suoli prelevati a Taranto e Altamura (BA), in siti contaminati da MP. Durante il campionamento, sono state individuate le zone a maggiore concentrazione di MP mediante fluorescenza portatile di raggi-X. I campioni sono stati sottoposti alle principali analisi chimico-fisiche, inclusa l’estrazione con DTPA. Il contenuto totale di MP è stato determinato con ICP-AES, dopo digestione acida in microonde. La distribuzione di MP nelle fasi solide del suolo è stata indagata mediante estrazioni sequenziali (metodo BCR modificato, 4 step), nonché analisi di microfluorescenza di raggi-X (μ-XRF) su sezioni sottili di suolo. Un’aliquota finemente macinata di ciascun campione è stata analizzata mediante diffrazione di raggi-X quantitativa e fluorescenza di raggi-X a dispersione di lunghezza d’onda. I due suoli di Taranto, simili tra loro per le proprietà fisico-chimiche (franco sabbiosi, calcarei, pH=8, Corg 2,8%) e mineralogiche, sono risultati caratterizzati da un contenuto elevato di Cu (229 e 140 mg/kg), Pb (415 e 292 mg/kg) e Zn (636 e 574 mg/kg). La frazione estratta in DTPA non ha superato il 12% (Cu), 17% (Pb) e 5% (Zn) rispetto al totale. Le estrazioni sequenziali hanno rivelato che oltre il 92% di questi MP è associato alle frazioni recalcitranti del suolo. In media, il 76% (Cu), 60% (Pb) e 77% (Zn) sono stati determinati nella frazione residua, e il 22% (Cu), 36% (Pb) e 16% (Zn) al termine del IV step (frazione potenzialmente legata alla sostanza organica e ai solfuri). Le mappe μ-XRF hanno rivelato una distribuzione eterogenea di Cu, Pb e Zn, con spot ad elevata concentrazione di dimensioni variabili. I tre MP sono risultati spesso associati tra loro, facendo ipotizzare la presenza di leghe metalliche (stagno al Pb) riconducibili ad attività militari pregresse svolte nel sito. Tali risultati, unitamente ai dati ecotossicologici che hanno rivelato l’assenza di fitotossicità dei suoli, dimostrano la limitata mobilità e disponibilità dei tre MP. Tuttavia, i livelli di Pb misurati nell’estratto di DTPA superano i valori mediamente riscontrati in suoli prossimi a reti stradali, indicando un potenziale rischio ambientale per questo elemento. I dati relativi al sito di Altamura sono in fase di acquisizione. ACKNOWLEDGEMENTS La ricerca è stata finanziata dal Programma “Future in research” (UE, Regione Puglia, A.R.T.I.).

L'inquinamento dei suoli da metalli pesanti comporta problemi sia ambientali che per la salute umana. L’impiego di piante accumulatrici di metalli in processi di phytoremedation rappresenta una possibile strategia di risanamento ambientale. Tuttavia, per le piante coltivate, come il riso, l’interesse è perlopiù rivolto all’identificazione di genotipi in grado di ridurre l'assunzione giornaliera di metalli pesanti come il cadmio (Cd) attraverso la dieta. I meccanismi che regolano l’accumulo di Cd nella pianta sono molto complessi e controllati da molteplici geni. Un aspetto importante che influenza la capacità di acquisizione degli elementi dal suolo è l’architettura radicale. La plasticità dell’apparato radicale consente alla pianta di esplorare diverse zone del suolo in risposta alle necessità della pianta stessa ed alle condizioni specifiche del suolo. Nonostante la sua importanza, poche sono le informazioni relative al contributo che le diverse componenti dell’architettura radicale - quali la lunghezza delle radici ed il root growth angle - possono fornire allo studio dei meccanismi di acquisizione dei metalli pesanti. Una precedente caratterizzazione dello ionoma della granella di una popolazione di 281 varietà di riso ha evidenziato differenze significative nella capacità di accumulo di Cd delle varietà Capataz (alto contenuto di Cd) e Beirao (basso contentuto di Cd). La successiva caratterizzazione fisiologica e molecolare ha permesso di evidenziare come il minor accumulo di Cd nella granella di Beirao fosse attribuibile ad una sua maggiore capacità di ritenere il metallo nelle radici, limitandone così la traslocazione alla parte epigea. In questo lavoro, piante di Capataz e Beirao sono state allevate in rhizobox utilizzando un suolo di risaia. Dalle immagini acquisite dell’apparato radicale è stato possibile stimare una maggiore capacità di esplorazione del suolo di Capataz rispetto a Beirao. Tuttavia l’esperimento condotto in rhizobox consente solo un’analisi bidimensionale dell’apparato radicale. Per ottenere informazioni tridimensionali, è stata avviata un’indagine mediante micro-tomografia computerizzata di assorbimento di raggi-X ad alta risoluzione (X-ray microCT), tecnica di imaging che consente di indagare la struttura interna di oggetti radio-opachi in maniera non distruttiva. Tale approccio infatti rende possibile lo studio dell’apparato radicale direttamente nel suolo, quindi senza minimamente alterarne l’architettura, eseguendo la scansione dell’intero contenitore in cui la pianta è coltivata. A tal scopo, un protocollo analitico è attualmente in fase di allestimento per l’ottimizzazione delle acquisizioni.

L‟arsenico (As) presente nell‟ambiente è estremamente tossico soprattutto nelle sue forme inorganiche per gli uomini, gli animali e le piante. La sua pericolosità può essere valutata attraverso analisi di bioaccumulo ed ecotossicità in organismi bioindicatori. I lombrichi sono potenti bioindicatori di suoli inquinati grazie alla loro capacità di ingerire le particelle del suolo e di avere la superficie corporea continuamente a contatto con il suolo. Il presente lavoro mostra i risultati di analisi di bioaccumulo ed ecotossicità nei lombrichi Eisenia andrei (Bouché) in suoli contaminati da attività minerarie e industriali che presentano differenti e crescenti concentrazioni di As (35, 60, 170, 730, 3000 e 14000 μg·g-1). Lombrichi adulti sono stati esposti a microcosmi contaminati e successivamente adoperati per saggi biologici e chimici. Dopo due giorni di esposizione è stato eseguito un avoidance test sul suolo contaminato; dopo 14 giorni sono stati misurati il tasso di sopravvivenza, la variazione in peso, il contenuto in metallotioneine, lo stress ossidativo e genotossico; dopo 28 giorni è stata valutata la capacità riproduttiva (OECD Test). La distribuzione e il bioaccumulo dell'As nei lombrichi sono stati determinati mediante spettroscopia di microfluorescenza di raggi X (μXRF) e fluorescenza di raggi X a riflessione totale (TXRF). I suoli contaminati sono stati evitati dai lombrichi in tutte le tesi tranne che in quella ad alto contenuto di sostanza organica; in nessun caso l‟esposizione ai suoli contaminati è stata letale dopo 14 giorni; anche il contenuto di metallotioneine e il danno genotossico non sono risultati differenti dal controllo; al contrario il tasso di riproduzione e l‟incremento in peso hanno mostrato una correlazione negativa con la quantità di As e, in tutte le tesi, lo stress ossidativo è risultato maggiore rispetto al controllo. Le analisi effettuate nelle sezioni trasversali dei lombrichi e nei fluidi celomatici mediante μXRF e TXRF hanno evidenziato un notevole accumulo dell‟elemento nella cavità celomatica. Per una migliore interpretazione dei risultati sono in corso ulteriori test per valutare altri biomarkers (stabilità lisosomiale, malondialdeide, enzimi antiossidanti come catalasi, superossidodimutasi e glutatione S-transferasi).

Arsenic concentration and distribution were studied by combining laboratory X-ray-based techniques (wavelength dispersive X-ray fluorescence (WDXRF), micro X-ray fluorescence (μXRF), and X-ray powder diffraction (XRPD)), field emission scanning electron microscopy equipped with microanalysis (FE-SEM-EDX), and sequential extraction procedure (SEP) coupled to total reflection X-ray fluorescence (TXRF) analysis. This approach was applied to three contaminated soils and one mine tailing collected near the gold extraction plant at the Crocette gold mine (Macugnaga, VB) in the Monte Rosa mining district (Piedmont, Italy). Arsenic (As) concentration, measured with WDXRF, ranged from 145 to 40,200 mg/kg. XRPD analysis evidenced the presence of jarosite and the absence of any As-bearing mineral, suggesting a high weathering grade and strong oxidative conditions. However, small domains of Fe arsenate were identified by combining μXRF with FE-SEM-EDX. SEP results revealed that As was mainly associated to amorphous Fe oxides/hydroxides or hydroxysulfates (50-80%) and the combination of XRPD and FE-SEM-EDX suggested that this phase could be attributed to schwertmannite. On the basis of the reported results, As is scarcely mobile, even if a consistent As fraction (1-3 g As/kg of soil) is still potentially mobilizable. In general, the proposed combination of laboratory X-ray techniques could be successfully employed to unravel environmental issues related to metal(loid) pollution in soil and sediments.

Arsenic (As) is a metalloid element, often found in soils and wastes around mines and industrial sites treating As-bare minerals. The assessment of the bioavailability of As in these soils is crucial in order to protect human and ecosystems health. Earthworms are often used to assess the bioavailability of As in soils (Langdon et al., 2003). In this work, Eisenia andrei was exposed to As-polluted soils from two sites in Italy (Valle Anzasca and Scarlino). Different X-ray based techniques and bioassays were used to evaluate the concentration, speciation and distribution of the As both in soils and earthworms.

Arsenic (As) is a metalloid, naturally associated with gold, sulphur, iron and heavy metals and is often found in soils and wastes around former mines and industrial sites because of the processing of As-bare minerals. Assessment of the bioavailability of As in these soils is very important in order to protect human and ecosystems health. Earthworms are often used to assess the bioavailability of As in soils (Langdon et al., 2003). In this work, Eisenia andrei was exposed to As-polluted soils from Valle Anzasca and Scarlino (Italy) in order to evaluate the bioavailability of As. Different X-ray based techniques were used to evaluate the concentration and the distribution of As both in soils and earthworms. For this study, three soil samples per polluted site were collected, sieved (2 mm) and dried. The mineralogical characterization of the soils was carried out by X-ray powder diffraction (XRPD). The total As was estimated on site via portable X-ray fluorescence (XRF), while sequential extractions (Wenzel et al., 2001) coupled with total reflection XRF (TXRF) were used to study the mobility of As. Soil elemental maps were acquired using micro XRF (µXRF) in order to evaluate the As distribution and its correlation with other elements. All the above analyses were conducted also on two control soils. For the assessment of the bioavailability, ten sexually mature earthworms were exposed to each contaminated soil and controls. The mortality was assessed after 14 days of exposure (acute toxicity). Oxidative stress was estimated by mesauring H2O2, catalase, phenoloxidase, glutathione S-transferase and malondialdehyde. The effect of As on the reproduction (chronic toxicity), was assessed after 28 days of exposure. Earthworms were embedded in epoxidic resin and thin sections (100 μm thickness) were analyzed via μXRF in order to localize As accumulation. Since detoxification mechanisms seem to act mainly inside the coelom (e.g. for Cd, Panzarino et al., 2016), coelomic fluids (few µl) were electrically extruded from worms and analysed by TXRF in order to quantify the As concentration....

In this study, we provide experimental evidences that in calcareous soils microbial degradation/decomposition of citrate can promote Al-(hydr)oxide precipitation concurrently decreasing copper (Cu) solubility by a coprecipitation process. Citrate is an organic acid anion commonly released by roots to increase nutrient availability or to limit Al toxicity. However, under specific environmental conditions (i.e. high microbial activity of Al-citrate-degrading bacteria, alkaline pH), this organic acid may become ineffective in mobilizing Cu for the plant acquisition process. To demonstrate this, a calcareous soil and an artificial soil system have been treated with citrate solutions; then, changes in Al and Cu solubility and the formation of Cu-containing Al-(hydr)oxides were monitored. Both in experiments with the artificial soil and in those where the soil was inoculated with microbial strains, the formation of Cu-Al coprecipitates not only occurred but was also concurrent with the decrease of Cu and Al solubility. The role of bacteria in metal-citrate complex degradation has been assessed, and the 16S rDNA of bacteria related with these processes has been sequenced for genus identification. Bacteria belonging to Pseudomonas, Sphingomonas, Bradyrhizobium and Sphingopixis have been identified as possible candidates to degrade Al- and Cu-citrate complexes thus triggering the metal precipitation phenomena.

La comprensione dei meccanismi attraverso cui la pianta percepisce la diversa biodisponibilità dei nutrienti nel suolo e regola la loro complessa interazione nei tessuti rappresenta un importante obiettivo della ricerca per lo sviluppo di pratiche agricole sostenibili. Questo lavoro ha lo scopo di investigare le interazioni tra il ferro (Fe) ed altri micronutrienti. Piante di cetriolo allevate in carenza di Fe (-Fe) mostravano una notevole alterazione del profilo ionomico fogliare. In particolare, il contenuto di zinco (Zn) aumentava del 300% in foglie Fe-carenti rispetto a quello di piante controllo. Il meccanismo alla base dell'interazione Fe-Zn è tuttavia poco noto. Perciò, in questo lavoro è stata avviata, mediante diversi approcci analitici, un’indagine a livello subcellulare volta ad identificare dove questa interazione potesse principalmente realizzarsi all'interno delle cellule fogliari, valutando il contenuto di Fe e Zn nelle diverse frazioni cellulari. E’ stato stimato che l’80% del Fe nelle cellule fogliari è localizzato nei cloroplasti. Di conseguenza, una frazione arricchita in cloroplasti è stata purificata da tessuti fogliari di piante di cetriolo allevate in presenza ed in assenza di Fe. Analisi condotte mediante spettroscopia ICP-MS hanno rilevato una diminuzione del contenuto di Fe del 90% ed un aumento (+60%) del contenuto di Zn in cloroplasti –Fe rispetto a quelli di piante controllo. Risultati simili (+48%) sono stati osservati anche nella frazione arricchita in mitocondri, ottenuta da foglie –Fe rispetto a quelle controllo. Per dettagliare la distribuzione subcellulare del Fe e dello Zn, sezioni dello spessore di circa 100 nm di foglie di piante -Fe e piante controllo sono state analizzate mediante fluorescenza di raggi X con luce di sincrotrone presso lo European Synchrotron Radiation Facility (ESRF) di Grenoble (Francia). I tessuti fogliari sono stati fissati chimicamente, inclusi in resina e posizionati su apposite griglie di SiN. Le analisi sono state effettuate a 17 keV con una risoluzione spaziale variabile fra 10 e 100 nm. La concentrazione di Fe nei tessuti non era sufficiente per ottenere delle immagini di buona qualità relativamente alla distribuzione di questo elemento negli organelli subcellulari. E' invece stato possibile visualizzare chiaramente la distribuzione dello Zn all'interno delle cellule vegetali. Tramite un'analisi semiquantitativa, è stato possibile osservare un aumento dell'85% del contenuto di Zn nei cloroplasti -Fe rispetto al controllo. Un simile aumento è stato osservato anche in altri organelli, tuttavia non è stato possibile discriminare tra mitocondri e perossisomi, in quanto la risoluzione della tecnica non ha consentito di visualizzare le ultrastrutture interne di tali organelli e quindi di differenziarli. Questa indagine ha permesso di valutare, mediante diversi approcci analitici, la distribuzione subcellulare dello Zn in piante sottoposte a carenza di Fe, identificando il cloroplasto come una delle possibili sedi nella cellula in cui avviene la maggiore interazione tra l’omeostasi del Fe e dello Zn.

Plants can cope with Fe deficiency by either acidifying the rhizosphere and enhancing the ferric chelate reductase activity (strategy I) or by releasing high affinity complexing compounds known as phytosiderophores (strategy II). In this research, tomato, barley and cucumber plants were grown hydroponically in an Fe free (–Fe) nutrient solution using the RHIZOtest. Fe-deficient (–Fe) plants were grown on a calcareous agricultural soil and root. Root exudates were determined quali-quantitatively using HPLC and colorimetric analyses. The accumulation of nutrients in plant tissues was measured by ICP-OES. Soil mineral modifications were assessed by XRD and SEM-EDX. Root exudates obtained by the hydroponic system were higher than those obtained from the soil extracts; plant uptake and adsorption by soil particles could be, at least in part, responsible of this result. After a 6-day soil contact the plants show a visible recovery from Fe deficiency symptoms at leaf level suggesting the efficacy, of root exudate release in the mobilization of Fe into soluble soil forms and its uptake. Moreover, significant soil mineral modifications were observed. At last, organic ligands released in Fe-deficient soil conditions show very complex exudation patterns both in monocotyledonous and dicotyledonous plants. For instance, barley plants besides the dominant release of phytosiderophores also significant amounts of amino acids and traces of organic acids were found. The results of this research will enable to better understand the soil influence on the release of root exudates, the dynamics of mineral weathering in the rhizosphere and the capability of plant species to mobilize and take up poorly soluble Fe forms.

Ceramics are multiphase materials usually obtained by the firing of a mixture of clay, water and non-plastic inclusions. According to the raw materials and the production cycle used, ceramics can have different physical properties and, hence, different uses and applications. One of the field of applications in which ceramics are most used is masonry. Like other building materials (concrete, mortars, steel, etc.), ceramics must be subjected to several tests and must follow particular recommendations before the commercialization. One of these tests concerns the assessment of the ability of a ceramic to withstand freeze-thaw stresses (UNI EN 12371). This property is very important in particular for applications where temperature fluctuates around 0 °C. In these conditions, the cycling formation and dissolution of ice may cause the formation of fissures and cracks which can seriously damage the ceramics. In order to understand the causes that may led to structural and microstructural modifications of the ceramics, scanning electron microscopy (SEM) or optical microscopy (OM) observations are usually employed after freeze-thaw tests. However, for this kind of analyses, samples should be usually cut in thin sections or embedded in a resin that can cause further microstructural changes and do not allow to analyse the same sample after a series of freeze-thaw cycles. On the contrary, high-resolution micro x-ray computed tomography (μCT) is a non-destructive powerful method to investigate samples before and after treatments, without any sample preparation. In the present work, μCT equipped with a thermal stage has been used for the characterization of ceramic microstructures after several freeze-thaw cycles. Ceramics were prepared by mixing a kaolinitic clay with 10% (w/w) of water, molding by uniaxial pressing and then fired at 750 and 1000 °C. In order to study the effect of non-plastic inclusions, 5 % (v/v) of quartz or limestone were also added to the mixture. Six samples of 5x5x10 mm (per ceramic) were cut from ceramic briquettes and were subjected to freeze-thaw cycles according to the UNI EN 12371. One of the 6 samples, was also studied via μCT using a cooling stage in order to keep the temperature at -12°C. μCT was equipped with a W source (80 kV and 125 mA) and the following parameters were set up for the analyses: pixel size of 2.4 μm, rotation step of 0.13 deg (0-180 deg) and an exposure of 1980 ms. A 1 mm thick Cu filter was used to improve the signal to noise ratio. Results suggest that the presence of quartz reduces the resistance to freeze-thaw cycles, because the cracks produced by the α-β quartz phase inversion propagates into the ceramics after the crystallization of ice. In conclusion, the possibility to analyze the same sample after several cycles makes μCT a valuable method for the microstructural characterization of ceramic materials subjected to physical stress tests.

Sulphur (S) and iron (Fe) are an essential macro- and micronutrients for plant growth and development. A balanced supply of S and Fe for plants is of major importance since it has been demonstrated that plant capability to take up and accumulate Fe is strongly dependent on S availability in the growth medium and vice versa. In fact, that Fe deficiency adaptation requires the adjustment of S uptake and assimilation rate. Furthermore, it has been demonstrated that providing S above adequate concentrations may result in the improvement of Fe use efficiency in wheat plants and this S nutritional effect seems to be especially advantageous for plants grown under severe Fe limitation. Aim of this study was to evaluate whether and to what extent the changes in S nutrition affect Fe accumulation into grains and whether grain Fe concentrations are significantly correlated with the concentration of Fe in the vegetative tissue. This approach might represent an important tool to realize the improvement of the nutritional value of food crops by increasing Fe content (agronomic biofortification) through soil and crop management strategies which allow to may prevent Fe deficiency in crops without additional input of Fe fertilizers. Durum wheat plants were grown on sand/perlite mixture with sufficient (1.2 mM) and high (2.5 mM) S supplies and with 10 or 80 M Fe-EDTA during the life cycle. In particular, we will discuss the effect of S supply on plant growth parameters (fresh and dry weight and chlorophyll content) and on total S accumulation rate at both leaf and seed level. In addition, the relative changes of the leaf and seed ionome induced by different nutritional conditions were evaluated by using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Finally, whole seeds and seed sections were subjected toinvestigated with micro-focused X-ray fluorescence (XRF) imaging to clarify the elemental distribution maps.of several elements, including S and Fe. Significant differences in the concentration and distribution of a number of elements could be observed according to the different treatments.

Plants release in the rhizosphere flavonoids and organic acids which exert multifunctional roles. In a recent study, we observed that the flavonoid rutin, alone or combined with genistein or organic acids (citrate, malate, oxalate), usually present in plant exudates, mobilized Fe from a calcareous soil with a great efficiency. However, the effects of these exudates on soil mineralogy, especially on Fe-bearing minerals and clays, remained unexplored. This work aims at evaluating the changes in the mineralogical composition of a calcareous soil after 24h-treatment with an aqueous solution of rutin (35 μM), alone or combined with other flavonoids (10 μM) or organic acids (1 mM). After centrifugation, the solid fraction was dried, homogenized with corundum (internal standard) and analysed by X-ray powder diffraction (XRPD), using the Rietveld method for mineralogical quantification. XRPD analysis of the natural soil revealed the presence of calcite (57.0%), illite (17.9%), smectite (5%), quartz (4.2%), heulandite (2.8%), and amorphous phases (13%). No Fe-oxides and oxyhydroxides were detected. In all the treatments with rutin, the sum of illite and smectite considerably increased, compared to the natural soil, especially when rutin was combined with organic acids or genistein. Conversely, the amorphous residue decreased. It can be assumed that the increase of illite+smectite was caused by the transformation of the amorphous phases into clay minerals. Rutin and its combinations with organics possibly mobilized Fe from soil along with other cations which could then find suitable conditions to recrystallize as new forming clay minerals. Na, K, and Ca could enter in the interlayer regions of phyllosilicates, while Al and Si could induce the formation of new sheets. Although the variation in soil mineralogy could not be easily related to Fe mobilization, it was evident that some treatments producing the higher Fe solubilization showed also the higher increase of the illite+smectite fraction.

Il ferro (Fe) è tra gli elementi più abbondanti nel suolo, ma è scarsamente disponibile per le piante in condizioni di pH neutro e alcalino. In Fe-carenza, le dicotiledoni aumentano la disponibilità di Fe nella rizosfera essudando protoni e composti organici ad azione complessante e/o riducente, come acidi organici (AO), flavonoidi e amino acidi (AA). Sebbene il ruolo degli AO sulla mobilizzazione del Fe dal suolo sia stato accertato, resta da comprendere meglio quello delle altre classi di composti. Inoltre, è opportuno indagare sull‟effetto di tali essudati sulla mineralogia del suolo, data la connessione tra i processi di mobilizzazione/assorbimento dei nutrienti e l‟alterazione dei minerali. In questo studio, è stata valutata inizialmente la composizione degli essudati radicali di cetriolo (Cucumis sativus L.) allevato in Fe-sufficienza (+Fe) ed in Fe-carenza (-Fe). Il contenuto di AO, sostanze fenoliche e AA negli essudati delle piante –Fe è risultato nettamente superiore a quello delle piante +Fe. Successivamente, è stata studiata, in un sistema chiuso, l‟interazione tra un suolo calcareo e alcuni composti determinati negli essudati radicali, quali AO (citrato, malato, ossalato) e flavonoidi (quercetina, rutina, genisteina), sia da soli che in combinazione. Dopo 24 ore, è stata determinata la concentrazione di Fe in soluzione mediante ICP-OES, e la composizione mineralogica del suolo mediante XRD. Inoltre, è stata studiata l‟alterazione mineralogica nel suolo rizosferico di piante di cetriolo +Fe e –Fe usando un sistema rhizotest. Nel sistema chiuso, la rutina, sia sola che combinata con gli AO o con la genisteina, ha estratto una quantità di Fe almeno due volte maggiore di quella estratta dal citrato; inoltre, ha dissolto tra il 12% ed il 41% delle fasi amorfe del suolo, ed ha favorito la neosintesi di illite e smectite. Nel suolo rizosferico, il cetriolo –Fe ha dissolto il 55% di amorfo, senza tuttavia promuovere la formazione dei fillosilicati. Pertanto, si può ipotizzare che, nel sistema chiuso, gli elementi liberati dall‟amorfo siano rapidamente precipitati a formare fillosilicati, mentre, nel sistema aperto (suolo rizosferico), tali elementi vengano assorbiti dalla pianta o lisciviati, sottraendosi così alla cristallizzazione. Esperimenti condotti con altre specie vegetali hanno dimostrato che l‟alterazione e la neosintesi dei minerali sono influenzate dalla strategia di mobilizzazione del Fe adottata dalla pianta.

A clean and cheap procedure for the synthesis of zeolites is presented, using glass and aluminum wastes as starting materials. The products are aluminosilicate materials with a high cation exchange capacity (CEC: 259-389.5meq/100g) containing 25-30% of crystalline zeolites. Since the synthesized materials are free of potentially toxic elements, they could be safely used for environmental and agricultural applications. More specifically, a material containing 30% of zeolite A has been synthesized at 60°C in one week, using NaOH as mineralizing agent. About 15% of zeolite A has been obtained at room temperature in six months. When KOH was employed, 25% of edingtonite has been produced in the final material after one week at 90°C. All the materials have been characterized for crystallinity, crystal morphology, particle size, pore size, surface area, and CEC. The whole process has been designed with the aim to recycle useful waste materials and reduce at minimum energy consumption and the production of harmful greenhouse gases.

Iron (Fe) deficiency is one of the major agricultural problems which highly affects the production of cultivated plants, especially in calcareous soils. Therefore, studying Fe uptake and homeostasis in plants is extremely important to develop new agricultural practices aiming at increasing Fe availability in soil for plant nutrition. However, determining Fe concentration and distribution in plants by XRF methods is not always simple, especially in Fe-deficient plants, where Fe concentration can be even below 1 ppm. In this study we investigated the potentiality of different XRF techniques to detect, quantify and map Fe distribution in different plant tissues. In particular, we used synchrotron micro-XRF to map quantitatively Fe in leaf and root (with a confocal geometry) tissues. For comparison, Fe maps were also acquired by using laboratory micro-XRF instruments, both commercial and in-house built. Advantages and limitations, in comparison to synchrotron-based methods will be discussed. In particular, Fe distribution was investigated in leaves of cucumber plants (Cucumis sativus L.) grown in different conditions (-Fe, +Fe, +Fe-chelates) whit three laboratory micro-XRF spectrometers, two polychromatic polycapillary focused micro-XRF and a mono-chromatic micro-XRF developed by the XMI Group at Ghent University. The data showed that, as expected, synchrotron XRF measurements gave better results in a shorter time. However, XRF laboratory instruments gave good results, which can be still useful for agronomic studies. While the mono-chromatic source gave a better signal to noise ratio, thus providing better spectra for quantitative evaluation even at low ppm levels, the two commercial instruments provided better maps (also thanks to the smaller beam size), which means more accurate information about Fe distribution throughout leaves tissues. TXRF is another XRF method very useful to quantify Fe in plant samples, even below 1 ppm level. This technique is particularly suitable to determine Fe concentration in xylem sap and plant tissues with a very limited sample preparation, thus reducing the costs and the artefacts caused by an extensive sample manipulation. Examples from plants grown in symbiosis with plant-growth-promoting-bacteria (PGPB) or cultivated with innovative agronomic practices will be presented. In particular, roots and leaves of cucumber were analysed as powder suspensions while samples of xylem sap, extracted from olive trees, were analysed directly. An increase of Fe concentration was observed in both root and leaves of cucumber treated with PGPB. On the contrary, no variation of Fe concentration was found in the xylem sap of olive trees. In conclusion, all these examples are intended to show the major advantages and limitations of using XRF techniques to study Fe homeostasis in plants and suggest the best XRF analytical approach to be adopted according to the specific case study.

This data article contains mineralogical and chemical data of the wulfenite (PbMoO4) sampled from mine of Fiumarella in Calabria region (Southern Italy). Wulfenite is a rare mineral belonging to the class of minerals called molybdates and if found in large amounts it can be used for the extraction of molybdenum. In the mine of Fiumarella, in addition to primary minerals such as barite, galena, cerussite, anglesite, fluorite and chalcopyrite, wulfenite was also detected. Wulfenite crystals are bipyramidal, few microns in size and grow as single crystals that can reach 1 mm. Methods for obtaining the data sets include optical microscopy, micro X-Ray Fluorescence and micro-Raman spectroscopy.

The modes of the archaeological documentation of prehistoric lithic tools has been widely debated among scholars for long time. In the recent years the introduction of new documentation techniques (e.g. 3D model and 3D scanner), besides the classic drawing, has increased the academic debating. Among these new documentation techniques, 3D photography is now commonly used while X-rays microtomography (μCT) has never be applied on chert artefacts. In the present work, graphite drawing, 3D photography and μCT are used for the techno-functional analysis. For this reason, four chert arrowhead (CN13, CN21, CN39, CN51) from the settlement of Coppa Nevigata (Bronze Age Southern Italy) were analysed with all these three techniques to retrace their different techno-functional sequences. Results show that μCT allows to detect more detachment areas and blows than graphite drawing and 3D photography. Moreover, internal defects and inclusions can be detected only by the use of μCT. In particular, CN39 shows an extensive internal cracking which can be imputed to a heating treatment. Furthermore, one surface of CN39 do not show any crack, which testify the removal of this portion in order to reuse the arrowhead after the heating event. In this way, μCT allowed to identify both a heating event and also its timing, since it occurred between the production and the retouch before a new use. In the case of CN51, the supposed heating identified after optical analysis seems not confirmed by μCT analysis. After the different analytical approaches, also the sample CN13 and CN21 do not show clear evidences of retouching and/or heating as archeologically supposed after optical analysis. Neither the stereoscope nor the 3D photography model give back the same informations obtained by μCT and highlight the potentials and limits of each one to detect microstructural details that can help to understand the techno-functional dynamics. The pros and cons of the old and the new documentation techniques were also discussed, in order to propose specific terms for microstructure description and interpretation.

La complessità e la varietà del sistema suolo pone problematiche metodologiche inerenti lo studio dell'inquinamento da parte di metalli pesanti. Lo sviluppo di metodologie analitiche che permettono di studiare campioni di suolo su scala micrometrica consente oggigiorno di analizzare e comprendere le interazioni che intercorrono tra l'inquinante e le varie componenti solide del suolo. Tra queste tecniche, la spettroscopia di microfluorescenza di raggi X a dispersione di energia (μXRF) è uno strumento molto utile in campo ambientale in quanto consente di effettuare in maniera non distruttiva l'analisi multielementare del campione, conoscere la distribuzione spaziale degli elementi in esso contenuti e quindi comprendere le relazioni tra i diversi elementi. In questo lavoro vengono presentati tre diversi casi di studio in cui l'uso della spettroscopia μXRF si è rilevato di fondamentale importanza per la comprensione della distribuzione e speciazione di metalli pesanti quali arsenico, cromo e rame. I campioni inquinati da arsenico provengono da siti di estrazione dell'oro (Valle Anzasca, Piemonte) e aree industriali (Scarlino, Toscana), mentre i suoli contenenti rame sono stati campionati in vigneti (Turi, Puglia). Infine, il suolo contaminato da Cr è un suolo sabbioso (Ginosa Marina, Puglia) su cui è stato simulato uno sversamento di Cr(VI) e su cui sono state condotte delle prove di risanamento mediante tecniche di solidificazione/stabilizzazione (S/S). Le analisi sono state eseguite su sezioni sottili di suolo (spessore 32 μm) impiegando uno spettrometro di microfluorescenza di raggi X equipaggiato con una sorgente policapillare di rodio (diametro del fascio 25 μm) e due detector SDD. Le analisi sono avvenute in vuoto (20 mbar), al fine di analizzare anche elementi leggeri (da Na a Cl), usando un tempo di acquisizione di 10 ms/px. Dalle analisi emerge che, per quanto riguarda il sito di Valle Anzasca, l'arsenico si trova sempre in associazione col ferro, formando delle deposizioni attorno a granuli di sabbia di quarzo e feldspati. Al contrario, nei suoli di Scarlino, As e Fe presentano distribuzioni differenti. Se nel primo caso i dati concordano con i risultati delle estrazioni sequenziali, nel secondo caso i risultati sono discordanti, in quanto le estrazioni sequenziali suggeriscono un legame dell'arsenico con fasi cristalline di Al o Fe. Il rame presente nei suoli agricoli pugliesi mostra una distribuzione abbastanza uniforme nel campione, molto probabilmente ascrivibile all'associazione del Cu con la sostanza organica del suolo, ma sono anche visibili correlazioni con lo zolfo, riconducibili all'impiego di CuSO4 come fungicida. Infine, in suoli inquinati da Cr(VI) e trattati in condizioni idrotermiche alcaline con scarti di vetro e alluminio da RSU si è osservato l'intrappolamento del Cr in macroaggregati di neoformazione contenenti Fe, Si, Al e K, la cui dimensione aumenta all'aumentare del tempo del trattamento. In conclusione, attraverso la microfluorescenza di raggi X è possibile determinare la distribuzione di metalli pesanti all'interno di campioni di suolo inquinati ed individuare eventuali correlazioni con altri elementi, al fine di comprenderne la speciazione. Inoltre, accoppiato ad altre metodologie di indagine, come le estrazioni sequenziali, consente di comprendere meglio la tipologia di legame tra l'inquinante e le componenti del suolo. Infine, la μXRF è uno strumento estremamente utile per valutare e mettere a punto processi di bonifica di suoli contaminati.

Gli insetti invasivi, alieni o da quarantena rappresentano una seria minaccia a scala mondiale e pongono problematiche complesse per le risorse agrarie quanto per quelle forestali. Le ricadute dei danni inflitti riguardano aspetti economici, paesaggistici e sociali. Fra questi insetti fitofagi, il Rhynchophorus ferrugineus (Olivier 1790), coleottero curculionide meglio noto come Punteruolo Rosso delle palme e diffusosi oltre i suoi habitat endemici a partire dagli anni ’80 del secolo scorso, è responsabile negli ultimi decenni della morte di palme economiche (Phoenix dactylifera) ed ornamentali (Phoenix canariensis) senza precedenti in numerose parti del mondo. Ad oggi infatti, nonostante le misure adottate e gli ingenti sforzi messi in atto per fronteggiare questa emergenza, il coleottero è ancora inarrestabile. In questo contesto la ricerca di base in entomologia gioca un ruolo chiave, spesso negletto. Infatti, la conoscenza accurata e mirata dell’interazione fra insetti infestanti e pianta ospite, ad esempio della loro capacità di trasmettere simbionti o dei loro meccanismi riproduttivi, è di fondamentale importanza proprio per l’elaborazione di efficaci strategie di controllo o gestione. Negli ultimi anni, la micro-tomografia computerizzata di raggi X ad alta risoluzione (HR micro- CT) si sta affermando come tecnica d’eccellenza per lo studio morfologico ed anatomico di un gran numero di insetti. Infatti, da un lato le dimensioni tipiche di questi organismi, in genere variabili da alcune centinaia di micron a qualche centimetro, dall’altra la presenza di esoscheletro ed altre strutture sclerotizzate (che in quanto più dense garantiscono un forte contrasto rispetto ai restanti tessuti più molli), consentono di acquisire dettagli ad altissima risoluzione (pixel size di circa 0,5 μm), ottenendo ricostruzioni ed immagini altamente descrittive. In aggiunta, la micro-CT consente di analizzare i campioni preservandone completamente l’integrità, a differenza delle tecniche più tradizionali che prevedono invece una distruzione più o meno parziale del campione, come per la preparazione di vetrini per microscopia ottica o microscopia elettronica. Questa peculiarità garantisce la possibilità di descrivere le strutture interne senza dover sezionare fisicamente l’organismo, riducendo le operazioni di preparazione del campione e il rischio di creare artefatti. Infine, l’analisi tomografica può essere molto utile per effettuare un’indagine preliminare non distruttiva del campione, sul quale poi effettuare successive indagini distruttive (ad esempio individuare i piani migliori per effettuare sezioni, etc.).In questo contributo, l’applicazione della micro-CT per lo studio dell’ultimo tratto dell’apparato riproduttore della femmina del punteruolo rosso ha consentito di verificare la posizione a riposo all’interno della Base Vaginale di una coppia di tasche rivestite di cuticola, sub-coniche e precedentemente identificate forzandone l’eversione [1], oltre alla possibilità di formulare nuove ipotesi sulla loro funzione. Infatti, l’analisi tomografica in 3D ha mostrato la presenza in queste tasche di un ingentissimo numero di nematodi. Tali organismi, potrebbero essere trasmessi alla pianta ospite durante l’ovodeposizione, suggerendo un ulteriore ruolo del punteruolo come vettore degli stessi. Queste analisi hanno inoltre fornito immagini anatomiche di notevole dettaglio, che rappresentano un ragguardevole passo in avanti rispetto all’attuale stato dell’arte (Fig. 1). Tale tecnica si è rivelata estremamente efficace per lo studio del punteruolo rosso e potrà essere impiegata in futuro per lo studio di altri insetti di interesse agrario e forestale.

La definizione di strategie sostenibili per il rimedio dei suoli inquinati da metalli pesanti rappresenta una delle principali sfide ambientali, considerato che i metalli pesanti non sono degradabili e quindi tendono ad accumularsi nel suolo. Tra le diverse metodologie di bonifica, quella della stabilizzazione/solidificazione (S/S) è sicuramente una delle più efficaci ed economicamente vantaggiose. Essa consiste nell’apporto al suolo di materiali e/o reagenti chimici capaci di ridurre la solubilità e la tossicità degli inquinanti e/o di immobilizzarli all’interno di fasi solide di neosintesi. In questo studio, è stato testato un metodo innovativo di S/S per la stabilizzazione del cromo esavalente (Cr(VI)) in un suolo sabbioso mediante l’impiego di materiali di scarto, quali vetro e alluminio provenienti da RSU, in condizioni idrotermiche alcaline. L’obiettivo è stato quello di valutare la capacità della tecnica di S/S di ridurre il Cr(VI) a Cr(III), forma meno tossica e molto stabile nel suolo, e di immobilizzare successivamente il Cr(III) in minerali di neoformazione. Il suoloè stato inquinato artificialmente con una soluzione di K2Cr2O7 fino a 1500 mg kg-1 (Cr totale) e lasciato poi indisturbato per 3 mesi fino a stabilizzarsi ad una concentrazione finale di 580 mg kg-1 di Cr(VI). E' stato quindi addizionato con una miscela di vetro e alluminio polverizzati e KOH (MIX), in rapporto di 1/10 e 1/20 (MIX:suolo, m/m). I campioni di suolo+MIX sono stati trasferiti in barattoli di HDPE, addizionati con acqua (1:2 m/v) e conservati in stufa a 90°C. Due controlli di suolo senza MIX, trattati a 90°C solo con KOH e solo con acqua, sono stati preparati in contemporanea. Dopo 1, 7, 30 e 60 giorni è stata prelevata da ciascun barattolo un’aliquota di suolo per la determinazione del Cr(VI) e le estrazioni sequenziali del Cr . Inoltre, al fine di comprendere i meccanismi di stabilizzazione del Cr, i campioni sono stati sottoposti ad analisi mineralogica mediante diffrazione di raggi X (XRPD), e di micro fluorescenza di raggi X (µ-XRF). Il trattamento S/S ha prodotto una netta e rapida diminuzione della concentrazione di Cr(VI) nel suolo, soprattutto in presenza di MIX. Dopo soli 7 giorni, la concentrazione di Cr(VI) nel suolo+MIX si è ridotta del 94% e 98% rispetto a quella iniziale (per le miscele 1/10 e 1/20, rispettivamente). Nei campioni controllo, la riduzione è stata invece del 71% (controllo con KOH) e 85% (controllo senza KOH). Prolungando il trattamento fino a 60 giorni, le concentrazioni di Cr(VI) si sono ridotte ulteriormente, risultando il trattamento con MIX sempre quello più efficace (sia 1/10 che 1/20). Inoltre, in presenza di MIX, la mobilità del Cr si è significativamente ridotta rispetto ai controlli, come dimostrato dalle estrazioni sequenziali. Infatti, già dopo 7 giorni ben il 95% e 87% del Cr totale è apparso legato al suolo in forme stabili (per le miscele 1/10 e 1/20, rispettivamente), mentre nei controlli solo il 55% e 38% del Cr è risultato stabilizzato nella fase solida (in presenza e assenza di KOH, rispettivamente). Nei successivi rilievi, la stabilità del Cr è aumentata considerevolmente nel tempo, anche nei controlli, senza tuttavia raggiungere i risultati ottenuti in presenza di MIX. L’analisi mineralogica ha rivelato in tutti i campioni una diminuzione di quarzo e illite e, in alcuni casi, la formazione di zeolite (edingtonite). Il trattamento idrotermico alcalino ha modificato profondamente la struttura del suolo, come dimostrato dall’analisi µ-XRF, e favorito l'intrappolamento del Cr in macroaggregati contenenti Si, K, Al, Fe e Mn. Ulteriori indagini microanalitiche sono in corso per studiare i meccanismi di inclusione del Cr in tali aggregati.

Il ruolo della componente biotica del suolo nei processi rizosferici di mobilizzazione e assorbimento dei nutrienti è ancora oggetto di ampia discussione. Tuttavia sono sempre più numerose le evidenze a supporto di un ruolo determinante svolto dai Plant growth-Promoting Rhizobacteria (PGPR) sull’accumulo dei nutrienti nei tessuti vegetali che è il risultato anche di ciò che accade alla rizosfera nei cicli biogeochimici dei diversi elementi/nutrienti. Pertanto, lo scopo di questo lavoro è stato quello di valutare gli effetti fisiologici e biochimici indotti dal PGPR Azospirillum brasilense su piante di cetriolo cresciute in un suolo calcareo. Inoltre, sono stati valutati anche gli effetti indotti dal rilascio di essudati radicali sulle componenti mineralogiche del suolo. A tale scopo, le piante di cetriolo sono state cresciute per 14 giorni in coltura idroponica in condizione di carenza di Fe e successivamente poste in contatto per 7 giorni con un suolo calcareo inoculato con A. brasilense. Al momento del campionamento, sono stati rilevati i parametri di crescita delle piante, i profili quali-quantitativi degli essudati rilasciati e il contenuto dei nutrienti nei tessuti. Inoltre, le variazione nella componente mineralogica del suolo sono state studiate mediante la tecnica XRPD (X-ray powder diffraction). I risultati ottenuti mostrano che la presenza di A. brasilense nel suolo facilita il recupero delle piante dalla clorosi ferrica, molto probabilmente tramite la modulazione dell’attività di essudazione della pianta, sia da un punto di vista qualitativo che quantitativo. In particolare, è stato evidenziato che due amminoacidi, la glicina e il glutammato, potrebbero essere coinvolti nell’interazione tra la pianta e il microrganismo nel processo di mobilizzazione del Fe dal suolo. L’analisi XRPD del suolo rizosferico di piante di cetriolo cresciute in carenza di Fe ha evidenziato una drastica riduzione della componente amorfa, probabilmente causata dal rilascio di amminoacidi, composti fenolici e acidi organici. In ogni caso, tali analisi hanno evidenziato che gli essudati rilasciati da piante di cetriolo carenti di Fe sono in grado di indurre modificazioni nella componente mineralogica del suolo calcareo in un breve lasso di tempo (7 giorni).

Iron (Fe) sources available for plants in the rhizospheric solution are mainly a mixture of complexes between Fe and organic ligands, including phytosiderophores (PS) and water-extractable humic substances (WEHS). In comparison with the other Fe sources, Fe-WEHS are more efficiently used by plants, and experimental evidences show that Fe translocation contributes to this better response. On the other hand, very little is known on the mechanisms involved in Fe allocation in leaves. In this work, physiological and molecular processes involved in Fe distribution in leaves of Fe-deficient Cucumis sativus supplied with Fe-PS or Fe-WEHS up to 5days were studied combining different techniques, such as radiochemical experiments, synchrotron micro X-ray fluorescence, real-time reverse transcription polymerase chain reaction and in situ hybridization. In Fe-WEHS-fed plants, Fe was rapidly (1day) allocated into the leaf veins, and after 5days, Fe was completely transferred into interveinal cells; moreover, the amount of accumulated Fe was much higher than with Fe-PS. This redistribution in Fe-WEHS plants was associated with an upregulation of genes encoding a ferricIII-chelate reductase (FRO), a Fe2+ transporter (IRT1) and a natural resistance-associated macrophage protein (NRAMP). The localization of FRO and IRT1 transcripts next to the midveins, beside that of NRAMP in the interveinal area, may suggest a rapid and efficient response induced by the presence of Fe-WEHS in the extra-radical solution for the allocation in leaves of high amounts of Fe. In conclusion, Fe is more efficiently used when chelated to WEHS than PS and seems to involve Fe distribution and gene regulation of Fe acquisition mechanisms operating in leaves.

La fluorescenza di raggi X a riflessione totale (TXRF) è una tecnica analitica emergente, che negli ultimi anni è stata applicata a un numero considerevole di materiali e settori spaziando dall'analisi dei semiconduttori alla caratterizzazione di prodotti agroalimentari. A differenza delle altre tecniche di fluorescenza di raggi X, il ridotto effetto di autoassorbimento da parte del campione consente di effettuare l'analisi chimica multielementare in tracce fino a livelli di ppb e sub ppb, risultando competitiva con altre tecniche più consolidate come l'ICP-OES. Nel presente lavoro la TXRF è stata impiegata per caratterizzare campioni biologici al fine di i) controllare la qualità di prodotti agroalimentari, ii) individuarne ”impronte digitali” ionomiche e iii) monitorare l'inquinamento ambientale in aree industriali. La caratterizzazione al fine del controllo di qualità è stata effettuata su frutti di pomodoro (Solanum lycopericum L.), alimento importante specialmente nella dieta mediterranea. Campioni di pesca (Prunus persica L.) sono stati analizzati per individuarne specifici “pattern” ionomici in grado di metterli in relazione con le pratiche agronomiche impiegate per la produzione. Infine, è stata condotta una caratterizzazione chimica multielementare di api bottinatrici (Apis mellifera L.) campionate da alveari opportunamente collocati in aree prossime a siti industriali e oggetto di monitoraggio ambientale. Le analisi sui frutti di pomodoro e le api sono state condotte sui campioni tal quali, essiccati e macinati per mezzo di un mulino planetario con giare in zirconio. Per le pesche, si è proceduto con l‟analisi del succo, estratto dalla polpa per centrifugazione, e del nocciolo, in seguito a macinazione. Le analisi hanno portato alla completa caratterizzazione elementare dei campioni di pomodoro rivelandone il contenuto di micronutrienti e senza evidenziare la presenza di alcun elemento potenzialmente nocivo per la salute umana. Nel caso delle pesche sono state individuate differenze nel profilo ionomico a seguito delle diverse pratiche agronomiche impiegate per la produzione. Infine, nelle api è stata registrata una variazione dei contaminanti ascrivibili alle attività industriali monitorate (principalmente Fe e Zn) nei diversi mesi dell'anno.

La micro-tomografia computerizzata di assorbimento di raggi-X (X-ray microCT) è una tecnica di imaging tridimensionale che consente di indagare la struttura interna di un campione in maniera non distruttiva. Nei comuni micro-tomografi da laboratorio il fascio conico di raggi-X (cone beam) emesso dalla sorgente radiogena incontra il campione rotante, e viene in parte assorbito ed in parte trasmesso, in maniera proporzionale al locale coefficiente di assorbimento µ (dove µ∝Z4). L’insieme delle proiezioni acquisite in corrispondenza di ciascuno step di rotazione del campione consente così una ricostruzione via software, che restituisce la distribuzione tridimensionale dei coefficienti di assorbimento nell’ambito dell’intero volume indagato. Le applicazioni della microCT sono le più trasversali, dalla medicina alle scienze dei materiali, dalle geoscienze all’informatica e così via. Vedere dentro un oggetto senza doverlo distruggere (tanto più importante quando il campione a disposizione è limitato, di particolare interesse scientifico o prezioso), eseguire analisi quantitative di porosità, volumi, superfici, osservare modificazioni strutturali in corrispondenza di prove di carico o cambiamenti termici controllati, rendono di fatto la microCT sempre più indispensabile nei moderni laboratori. In questa presentazione verranno mostrate alcune possibili applicazioni in campo Agrario, Ambientale ed Alimentare, ottenute mediante uno strumento da laboratorio con una risoluzione massima di 350 nm. In particolare, allo scopo di evidenziare alcune delle potenzialità della tecnica verranno mostrati i risultati relativi a campioni di:  Suolo: in base ai diversi valori di µ relativi alle frazioni principali, è possibile distinguerle e svelarne le caratteristiche morfometriche, quali volume, superficie, ecc. Laddove è presente un sufficiente contrasto fra le diverse componenti è anche possibile discriminare le diverse fasi mineralogiche, porosità e apparati radicali delle piante;  Biochar: ne può essere calcolata la porosità e la superficie attiva, parametri fondamentali per studiare il materiale come ammendante col suolo;  Semi: le strutture interne possono essere visualizzate e studiate senza "aprire" il seme;  Lombrichi: le caratteristiche morfologiche dell’organismo vengono mostrate con una risoluzione di pochi micron in modo da poter “entrare” nei diversi organi e visualizzarne una qualsiasi sezione;  Pane e prodotti da forno: può esserne determinata la struttura e la porosità al fine di migliorare la qualità del prodotto. I diversi esempi evidenziano come la microCT sia uno strumento molto importante per le moderne indagini analitiche grazie sia alla possibilità di imaging in senso stretto, sia per analisi quantitative di tipo strutturale (es. porosità, area superficiale), consentendo in alcuni casi notevoli miglioramenti in termini di consumo di tempo e di qualità del dato rispetto ad altre metodologie analitiche tradizionali.

Arsenic (As) is a metalloid element, naturally associated with gold, sulphur, iron and heavy metals and is often found in soils around former mines and industrial sites treating As-bearing minerals. The assessment of the bioavailability of As in these soils is very important in order to protect human and ecosystem health. Earthworms are the most used organisms to assess the bioavailability of As in contaminated soils. The present work aims at evaluating the bioavailability of As in six polluted soils sampled in the industrial area of Scarlino (Tuscany, Italy) and the gold mining site of the Anzasca Valley (Piedmont, Italy), using Eisenia andrei as a bioindicator and a multianalytical X-ray based approach. The soils were preliminary analysed in situ by portable energy dispersive X-ray fluorescence spectrometry (pEDXRF) which detected As concentrations ranging from 20 to 800 mg/kg in Scarlino, and from 20 to 20000 mg/kg in Anzasca Valley. X-ray powder diffraction (XRPD) detected no As-bearing mineral. Only in the most contaminated soil from Anzasca Valley, jarosite and goethite were detected as minerals formed as a consequence of the alteration of pyrite and arsenopyrite. In order to have more information about As speciation, micro X-ray fluorescence (μXRF) analysis were performed on soil thin sections, which showed the co-presence of Fe and As around quartz or feldspar grains. This is in accordance with the results of sequential extractions which indicated that As was mainly associated with amorphous and/or well-crystallized Fe oxides and hydroxides. To study As bioavailability, ten sexually mature earthworms were exposed to contaminated and control soils. After 14 days, mortality (which gives information about acute toxicity) and oxidative stress were measured. The chronic toxicity was estimated with reproduction tests after 28 days. μXRF analyses on earthworm thin sections revealed that As accumulates mainly in the coelomic cavity while no As was detected in other parts of the body. Given that As detoxification in earthworms seemed to involve mainly the coelom, coelomic fluids were electrically extruded and the As concentration was estimated via total-reflection X-ray fluorescence (TXRF) spectroscopy. In all cases, no earthworm died after 14 days of exposure to contaminated soils even if an oxidative stress was measured. A chronic toxicity was observed after 28 days with a reduction in new born organisms with the increase of As concentration. TXRF analyses on coelomic fluids suggested that the As concentration in the fluids was closely related with the As available fraction (adsorbed or loosely bound to Fe oxides and hydroxides) and not with the total As concentration in soils. In fact, when a consistent part of the As was associated with well crystallized Fe-hydrous oxides (the low available fraction) the concentration of As in the coelomic fluids was comparable to that found in earthworms exposed to control soils. Finally, this study showed the usefulness of laboratory x-ray based techniques for bioavailability studies and could be used as a base for the development of new procedures for the assessment of As bioavailability in contaminated soils.

This study was carried out in two olive orchards (Olea europaea L., cv. Chemlali) located in a polluted area near a fertilizers factory and in a control unpolluted site, managed with similar cultivation techniques. The aim was to investigate the physiological and biochemical responses of polluted plants (PP), exposed to atmospheric metal contamination (Cd, Cu, Fe, Mn, Ni and Pb) as compared to control plants (CP). Leaves, roots and fruits of PP showed a depression of their non-enzymatic and enzymatic antioxidant defences and a disruption of their hormonal homeostasis. The anomalous physiological status of PP was also demonstrated by the lower values of pigments in leaves and fruits, as compared to CP. Atmospheric metals negatively affected olive oil chemical and sensory quality. However, despite metal deposition on fruit surfaces, the accumulation of potentially toxic metals in olive oil was negligible. Considering that olive oil is an important food product worldwide and that many productive olive orchards are exposed to several sources of pollution, this work could contribute to clarify the effects of atmospheric metal pollution on olive oil quality and its potential toxicity for humans.

Background and purpose: Recycling waste materials by transformation into new useful products requires that both the starting raw material and the transformed commodity are chemically and physically characterized for safety and quality issues. In this context, X-ray analyses can provide valuable tools to non-destructively investigate the chemical composition as well as the internal structure of materials with trace-level sensitivity and (sub)micrometric resolution. Methods: At the Micro X-ray Lab different new generation X-ray-based instruments are available: a X-ray powder diffractometer (XRPD), a portable energy dispersive X-ray fluorescence (pXRF), a wavelength dispersive X-ray fluorescence (WDXRF), a total reflection X-ray fluorescence spectrometer (TXRF), a micro X-ray fluorescence spectrometer (μXRF), a high resolution X-ray microtomograph (μCT), and a variable pressure field emission scanning electron microscope (VP-FESEM) equipped with energy dispersive X-ray microanalysis (EDX). Results and Conclusions: The instrumentations available at the Micro X-ray Lab allow for fast non destructive chemical analyses of all types of solids and liquids, powders, suspensions and particles, from bulky materials down to nanometer sized samples. In addition, 2D chemical mapping and 3D volume rendering of different types of raw and transformed materials is possible. Such combined X-ray approach is used to support the development of new technologies in recycling waste materials.

Plant growth-promoting rhizobacteria (PGPR) are soil bacteria that are able to colonize rhizosphere and to enhance plant growth by means of a wide variety of mechanisms like organic matter mineralization, biological control against soil-borne pathogens, biological nitrogen fixation, and root growth promotion. A very interesting feature of PGPR is their ability of enhancing nutrient bioavailability. Several bacterial species have been characterized as P-solubilizing microorganisms while other species have been shown to increase the solubility of micronutrients, like those that produce siderophores for Fe chelation. The enhanced amount of soluble macro- and micronutrients in the close proximity of the soil-root interface has indeed a positive effect on plant nutrition. Furthermore, several pieces of evidence highlight that the inoculation of plants with PGPR can have considerable effects on plant at both physiological and molecular levels (e.g., induction of rhizosphere acidification, up- and downregulation of genes involved in ion uptake, and translocation), suggesting the possibility that soil biota could stimulate plants being more efficient in retrieving nutrients from soil and coping with abiotic stresses. However, the molecular mechanisms underlying these phenomena, the signals involved as well as the potential applications in a sustainable agriculture approach, and the biotechnological aspects for possible rhizosphere engineering are still matters of discussion.

A revegetation process of a closed urban solid waste landfill was initiated in 2009 for the environmental restoration of the site. The landfill is located in Foggia district in the North part of the Apulia region. Growth experiments in pots and in open field were carried out on eight plant species in order to select those that could be more appropriate in the particular extreme field conditions (climate, high slope of the walls, bad leachate control). In particular, plant growth was assessed in two different soil types (agricultural and leachate contaminated soil). Among the different species assessed, Pistacia lentiscus L. and Puccinellia borreri. L. were selected because of their performance in the contaminated soil and mostly since they are typical native Mediterranean plant species. Rhizosphere and bulk soil of these two plant species, sampled from the pots, has been characterized by biochemical and molecular methods in order to highlight shift in the composition of the microbial community caused by the presence of leachate. Enzymatic activities (dehydrogenase, fluorescein diacetate hydrolysis, ?-glucosidase and protease) and microbial biomass C were analyzed to evaluate the activity of microbial population of soils. The molecular characterization was carried out by the direct extraction of DNA, gene amplification of the 16S rRNA of the Eubacteria by PCR and specific groups such as the Actinomycetes and Ammonia-oxidizing bacteria. The amplification products were separated by DGGE under appropriate conditions of denaturation and the resulting genetic fingerprinting were analyzed using the software Bionumerics.

Arsenic (As) co-precipitation is one of the major processes controlling As solubility in soils and waters. When As is co-precipitated with Al and Mg, the possible formation of layered double hydroxides (LDHs) and other nanocomposites can stabilize As in their structures thus making this toxic element less available. We investigated the nature and reactivity of Mg-Al-arsenate [As(V)] co-precipitated LDHs formed in solution affected by As concentration, pH, and aging. At the beginning of the co-precipitation process, poorly crystalline LDH and non-crystalline Al(Mg)-oxides form. Prolonged aging of the samples promotes crystallization of LDHs, evidenced by an increase in As K XANES intensities and XRD peak intensities. During aging Al- and/or Mg-oxides are likely transformed by dissolution/re-precipitation processes into more crystalline but still defective LDHs. Surface area, chemical composition, reactivity of the precipitates, and anion exchange properties of As(V) in the co-precipitates are influenced by pH, aging, and As concentration. This study demonstrates that (i) As(V) retards or inhibits the formation and transformation of LDHs and (ii) more As(V) is removed from solution if co-precipitated with Mg and Al than by sorption onto well crystallized LDHs.

Soilless cultivation systems represent an alternative to traditional agriculture, as they offer the possibility to reduce water use and to design nutrient formulations of the hydroponic solutions in order to maximize yield and quality of the products. Reduction in accumulation of undesired compounds, like e.g. nitrate, and enhanced nutritional value for human consumption, like e.g. Se-rich compounds, could be reasonably achieved. These aspects, together with the extension of the shelf life, would increase the market value of ready-to-cut vegetables. This review discusses how recent advances in understanding the role of plant nutrients and their interactions and the management of nutrient solution composition, including the addition of non-essential elements, micronutrients' biofortification, biostimulants, together with the control of some crucial environmental conditions, like temperature, can help accomplishing this task.

Besides the variety of colours and flavours, microgreens show interesting nutritional properties, mainly regarding their contents of mineral nutrients and bioactive compounds. To date, the literature has prevalently focused on the individual nutritional features of microgreens usually belonging to Brassicaceae. The present study reports an articulated nutritional profile of six genotypes of microgreens, belonging to three species and two families: chicory (Cichorium intybus L., Puglia's local variety 'Molfetta', CM, and cultivar 'Italico a costa rossa', CR) and lettuce (Lactuca sativa L. Group crispa, cultivar 'Bionda da taglio', LB, and 'Trocadero', LT), from Asteraceae; and broccoli (Brassica oleracea L. Group italica Plenk, Puglia's local variety 'Mugnuli', BM, and cultivar 'Natalino', BN) from Brassicaceae. All the microgreens, except LB, can be considered good sources of Ca, whilst LT and CM also showed considerable amounts of K. As regards bioactive compounds, Brassica microgreens were the richest in phenolic antioxidants. The microgreens also presented higher amounts of α-tocopherol and carotenoids compared to mature vegetables. In particular, broccoli microgreens and LB showed the highest amounts of vitamin E, while Asteraceae microgreens presented the highest levels of carotenoids. Due to their delicate tissues, fresh cut microgreens showed a shelf life not exceeding ten days at 5 °C. The results obtained highlight the possibility to exploit genetic biodiversity in order to obtain tailored microgreens with the desired nutritional profiles, with particular regard to mineral nutrients and bioactive compounds. Appropriate pre- and post-harvest strategies should be developed, so as to allow microgreens to retain as long as possible their nutritional value.

La pericolosità dell'Arsenico (As) nei suoli è strettamente correlata alla sua speciazione, che ne influenza la frazione biodisponibile e quindi il reale rischio per le catene alimentari. Il presente contributo vuole fornire i risultati preliminari di analisi di speciazione, bioaccumulo e tossicità acuta e cronica nei lombrichi in suoli contaminati da attività minerarie e industriali che presentano differenti e crescenti concentrazioni di As (35, 60, 170, 730, 3000 e 14000 μg/g). I lombrichi sono potenti bioindicatori largamente usati in studi di ecotossicità di suoli inquinati grazie alla loro capacità di ingerire le particelle del suolo e di avere la superficie corporea continuamente a contatto con il suolo. Lombrichi della specie Eisenia andrei (Bouché) sono stati esposti a microcosmi contaminati e successivamente adoperati per saggi biologici e chimici. Dopo 14 giorni di esposizione il tasso di sopravvivenza, la variazione in peso e lo stress ossidativo dei lombrichi sono stati misurati per una stima della tossicità acuta. La stima della tossicità cronica è stata effettuata valutando la capacità riproduttiva dopo esposizione per 28 giorni (OECD Test). La distribuzione e il bioaccumulo dell'As nei tessuti dei lombrichi sono stati determinati mediante spettroscopia di microfluorescenza di raggi X (μXRF), che consente una mappatura e quantificazione elementare di sezioni dei lombrichi inclusi in resina epossidica. Su tutti i suoli sono state effettuate analisi chimiche e mineralogiche mediante spettrometria XRF (sui suoli tal quali) e μXRF (suoli in sezione sottile), e per diffrazione di raggi X su polveri (XRPD). I risultati preliminari mostrano che in nessun caso l’esposizione ai suoli contaminati è stata letale dopo 14 giorni; il tasso di riproduzione mostra una correlazione negativa con la quantità di As; in tutte le tesi lo stress ossidativo è risultato maggiore rispetto ai suoli di controllo. L’analisi della distribuzione dell’arsenico nelle sezioni trasversali dei lombrichi mediante μXRF ha evidenziato un notevole accumulo dell’elemento nella cavità celomatica piuttosto che nei tessuti. Campioni di fluido celomatico sono in fase di analisi mediante fluorescenza di raggi X a riflessione totale (TXRF) per determinarne il contenuto di As. Per una migliore interpretazione dei risultati sono in corso l’acquisizione di mappe di sezioni longitudinali dei lombrichi con la μXRF ed ulteriori test per valutare altri biomarkers (metallotioneine, malondialdeide, danno genotossico, enzimi antiossidanti come catalasi, superossido dimutasi e glutatione S-transferasi).

A proper soil risk assessment needs to estimate the processes that affect the fate and the behaviour of a contaminant, which are influenced by soil biotic and abiotic components. For this reason, the measurement of biomarkers in soil bioindicator organisms, such as earthworms, has recently received increasing attention. In this study, the earthworm Eisenia andrei was used to assess the pollutant-induced stress syndrome after exposure to sublethal concentrations of Cd (10 or 100 microg g-1) in OECD soil, after 14 d of exposure. Cadmium bioaccumulation and potential biomarkers such as catalase (CAT), hydrogen peroxide (H2O2), glutathione-S-transferase (GST), malondialdehyde (MDA), phenoloxidase (PO), metallothioneins (MTs) and genotoxic damage were determined. Results suggested that the exposure to 10 and 100 mg g1 Cd significantly increased Cd bioaccumulation, MTs and MDA; 100 microg g-1 Cd contamination evidenced significantly higher values of H2O2 content and PO activity; CAT activity was inhibited at the higher concentration while GST and Comet assay did not show any significant differences from the control. Rank-based biomarker index showed that both different contaminated soils had an effect on the earthworms and allowed to validate the ecotoxicological relevance of this battery of biomarkers for a promising integrated multi-marker approach in soil monitoring and assessment.

A new screening strategy using Petri dishes with a gradient of distances between germinating seeds and a metal-contaminated medium was used for studying alterations in root architecture and morphology of Arabidopsis thaliana treated with cadmium, copper and zinc at sub-toxic concentrations. Metal concentrations in the dishes were determined by anodic stripping voltammetry on digested agar samples collected along the gradient, and kriging statistical interpolation method was performed. After two weeks, all agar dishes were scanned at high resolution and the root systems analyzed. In the presence of all the three metals, primary root length did not significantly change compared to controls, excepting for zinc applied alone (+45% of controls). In metal-treated seedlings, root system total length increased due to the higher number of lateral roots. The seedlings closer to the agar sectors including metals showed a marked curvature and a higher root branching in comparison to those further away from the metals. This behavior, together with an observed increase in root diameter in metal-treated seedlings could be interpreted as compensatory growth, and a thicker roots could act as a barrier to protect root from the metals. We therefore propose that the remodeling of the root architecture in response to metals could be a pollution 'escaping strategy' aimed at seeking metal-free Patches.

Soil is an extremely heterogeneous matrix where organic and inorganic phases coexist with a variety of living organisms. In particular, the rhizosphere is a very dynamic environment where plants and microorganisms compete (or cooperate) for mineral nutrients. In such a dynamic system, thermodynamic previsions about chemical processes can be controverted by peculiar conditions, which may kinetically favor other unexpected reactions. It is widely accepted that low-molecular-weight organic acids released into the rhizosphere have complexing properties thereby enhancing the solubility of several mineral elements and increasing their availability for plant uptake. Among these, it is well known that citrate can increase mineral nutrients mobility (particularly Fe), especially in alkaline soils. However, experimental evidence showed that, in a calcareous soil (pH 8.2, CaCO3 61.8% w/w, Corg 0.86% w/w), citrate (0.1 mM and 1 mM) was not as effective in solubilizing Cu as Al, Fe and Mn from soil. In addition, Automated Particle Analyses (APA) using Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy (SEM-EDX) and Cluster Analysis evidenced the formation of a large number of aluminum oxide (AlOx) particles, about 50% of which containing a significant amount of Cu. In this research we demonstrated that in particular conditions of alkalinity and high microbial activity, which can be typically found in the rhizosphere of plants grown in calcareous soils, citrate efficacy in mobilizing Cu is strongly reduced by co-precipitation of the metal within Al (hydr)oxides. To prove this hypothesis, conditions similar to those occurring in the real soil (100% calcite, pH 8.2, [Al]=17 mg/l, [Cu]=7 mg/l) have been simulated, at first, by gradually reducing the concentration of citrate and thus mimicking the action of soil microorganisms feeding on citrate (as also observed experimentally) and, in a second step, by introducing soil microorganisms into the system. As a result, in both cases we observed a significant and concomitant decrease of Al and Cu solubility; then APA analyses on the solid phase revealed the formation of Cu-containing Al (hydr)oxides almost identical (in size, shape and composition) to those observed in the real sample. In addition, 16S rDNA PCR-DGGE of DNA extracted from the samples revealed changes in microbial communities suggesting that specific bacteria may be responsible for the degradation of citrate-metal-complexes. Sequencing of the main DNA gel bands allowed identification of these bacteria as Sphingomonax sp., Sphingopyxis sp. and Propionibacterium sp. In conclusion, in highly calcareous soils, citrate can be ineffective in mobilizing Cu from soil because specific soil microbes can degrade Al-citrate complexes thus causing the co-precipitation of soluble Cu within Al-(hydr)oxides and making it unavailable for plants.

In this research, the optimum growth conditions for two zinc solubilizing bacteria (ZSB) have been studied for their potential application as bioinoculants to overcome Zn unavailability in soils. For this purpose, a laboratory-scale experiment was carried out to evaluate the zinc solubilizing ability of 80 plant growth promoting bacteria (PGPB) strains isolated from the rhizosphere of barley and tomato plants. To select effective ZSB, isolates were evaluated on Tris-mineral medium supplemented separately with zinc oxide, zinc carbonate, and zinc phosphate at a concentration of 0.1%. Two strains (Agrobacterium tumefaciens and Rhizobium sp.) were selected, based on a clear halo zone around their colonies in the solid medium supplemented with zinc oxide after 10 days of incubation at 29 °C. Results of solubilization at different pH values showed that these strains had solubilization activity in the range of pH 8-10 while no solubilization was observed at pH 6 and 7. The maximum Zn solubilization values were noted at pH 9: 51.4 mg L-1 (Agrobacterium tumefaciens) and 72.1 mg L-1 (Rhizobium sp). According to findings, bacterial growth was affected by different NaCl concentrations under in vitro condition. The salt concentration required for 50% inhibition of absorbance was 2.11 and 2.27% NaCl for Agrobacterium tumefaciens and Rhizobium sp., respectively. The maximum bacterial growth was observed at about 0.8% NaCl concentration.

Iron is an essential element in plant nutrition and the determination of its concentration, location and chemical form is of paramount relevance to study Fe homeostasis in plants. Assessing the mechanisms of Fe uptake, transport and storage by plants is critical to overcome nutrition deficiencies for cultivated plants and to improve the nutritional value of food crops. For such studies, researchers need to visualize where iron is located at the level of the whole plant, the individual cell and the organelle. This requires a μm or sub-μm spatial resolution and a ppm or sub ppm detection sensitivity. Fe is not easy to analyze in plant materials because of its highly heterogeneous distribution with large differences in concentration, ranging from sub ppm to %, depending to its location. Especially the lower concentrations are hardly detectable with normal laboratory equipments (e.g., Electron Probe Micro Analysis, Proton Induced X-ray Emission). In this study, intact freeze dried leaves and roots of model plants such as tomato and cucumber have been studied for Fe distribution by scanning SXRF and confocal SXRF, without the need of sectioning. Quantification has been reached by using Fundamental Parameter algorithms coupled with standards analysis. With such an approach Fe distribution maps could be obtained with concentrations ranging from 100 ppb to 0,1%, with an accuracy of 2%. Such accurate distribution maps can be extremely useful to compare Fe allocation and concentration between plants altered with respect to the genes they express and/or the environmental conditions under which they are grown.

Lo studio dei meccanismi biogeochimici che regolano il destino dei metalli pesanti (MP) nei suoli inquinati è indispensabile al fine di comprendere il grado di mobilità e biodisponibilità dei MP e, quindi, il loro effetto sull’uomo e sull’ambiente. Quando l’inquinamento interessa il suolo agrario, è ancora più urgente la comprensione di tali dinamiche, al fine di ridurre al minimo i rischi di trasferimento dei MP dal suolo alla pianta e, attraverso la catena alimentare, all’uomo. Il suolo possiede una propria capacità naturale di attenuazione dell’inquinamento da MP, che si esplica nei processi di complessazione da parte della sostanza organica, adsorbimento sulle superfici dei colloidi, intrappolamento nelle microporosità dei minerali primari e secondari, nonché precipitazione e coprecipitazione. Lo studio di tali importanti fenomeni richiede l’ausilio di tecniche in grado di risolvere l’estrema complessità del sistema suolo fino a livelli micrometrici. Nel presente lavoro, molteplici tecniche di analisi di raggi-X sono state utilizzate, congiuntamente a tecniche convenzionali, per indagare la distribuzione e l’eventuale immobilizzazione del Cr e altri MP (Zn, Pb e Cu) in un suolo agrario pugliese sottoposto nel passato ad ammendamento con compost miscelato a rifiuti di provenienza incerta. È stata condotta sui campioni di suolo una caratterizzazione chimico-fisica di base, che ha consentito di accertare la presenza, in media, di un elevato contenuto di Corg (130 g kg-1) e CaCO3 (105 g kg-1), nonché Cr e Zn in concentrazioni molto elevate (4480 e 1220 mg kg-1, rispettivamente), e livelli di Cu e Pb meno allarmanti ma comunque superiori ai limiti di legge. Le estrazioni sequenziali con il metodo BCR hanno rivelato la scarsa mobilità di Cr, Cu e Pb, tutti prevalentemente associati alle componenti organiche del suolo e ai minerali della frazione residua, ed una discreta mobilità dello Zn, distribuito per circa il 40% nella frazione riducibile o associata ai carbonati. La concentrazione di Cr(VI) è stata determinata con i metodi ufficiali USEPA (3060A e 7196A); tuttavia l’elevato contenuto di sostanza organica del suolo ha interferito negativamente sul metodo, dando recuperi pari a zero. L’analisi di diffrazione di raggi-X (XRD) ha evidenziato la presenza di calcite, quarzo, illite, rutilo, caolinite e albite, e l’assenza di minerali cristallini contenenti Cr o altri MP. L’analisi di fluorescenza di raggi-X a dispersione di lunghezza d’onda (WD-XRF) ha rivelato che il suolo inquinato ha un minore contenuto di Al e Si ed un maggiore contenuto di Ca, P e S rispetto al suolo di controllo (campionato nella stessa zona e non inquinato). L’analisi con microfluorescenza di raggi-X (μ-XRF) su sezioni sottili di suolo ha evidenziato la presenza diffusa di Cr, che è apparso distribuito in particelle di dimensioni variabili (da pochi micrometri a qualche millimetro). Il Cr è risultato associato a Ca, Zn, P, S e Fe, ma non a Si e Al. L’elaborazione degli spettri acquisiti per ciascun pixel della mappa di microfluorescenza ha consentito di indagare le correlazioni tra gli elementi. Lo studio della correlazione Si-Al (Fig. 1a) ha rivelato la presenza nel suolo di due frazioni, una alluminosilicatica di tipo autoctono (Fig. 1a, in verde), e una alloctona (assente nel suolo di controllo), quest’ultima ricca in Cr ma povera in Si e Al (Fig. 1a, Cr in scala di grigio). Numerose particelle contenenti Cr sono apparse circondate da un bordo alluminosilicatico, ben evidente soprattutto nelle particelle di dimensioni minori. L’analisi di microscopia elettronica a scansione accoppiata alla microanalisi (SEM-EDX) delle sezioni sottili e delle singole particelle di suolo ha confermato la presenza, nelle particelle, di uno strato esterno alluminosilicatico, e di una porzione interna ricca in Cr, Ca, Fe, P, S e Zn (Fig. 1

Qual è il rischio per la salute umana nell‟impiego di suoli contaminati da arsenico (As) in agricoltura o per il pascolo? Come è noto, non è tanto la concentrazione totale del contaminante a costituire di per sé una minaccia, quanto la sua distribuzione nelle diverse forme chimiche (speciazione), che ne influenza la frazione biodisponibile e quindi le sue possibilità di entrare nella filiera alimentare. E‟ in questa direzione che si muove il presente lavoro, volto a determinare il rischio reale che deriva dalla presenza di As in suoli campionati in aree pertinenti ad ex attività industriali (Scarlino, GR) e minerarie (Valle Anzasca, VB), con concentrazioni tra le decine ad alcune migliaia di ppm. È così stato adottato un duplice approccio, mirato ad ottenere da un lato una puntuale caratterizzazione chimico-mineralogica dei suoli stessi e quindi informazioni circa la speciazione dell‟As, dall‟altro a valutarne la biodisponibilità e l‟ecotossicità. Le analisi chimiche e mineralogiche dei suoli sono effettuate mediante tecniche che impiegano radiazione X; in particolare la caratterizzazione chimica in situ viene condotta tramite spettrometria di fluorescenza portatile con rivelatore a dispersione di energia (ED-pXRF), e in laboratorio mediante dispersione di lunghezza d‟onda (WD-XRF). In via preliminare esse hanno permesso di individuare nei suoli di Valle Anzasca una certa correlazione tre le concentrazioni rispettivamente di As e Fe e di As e S. La caratterizzazione mineralogica è invece condotta con un diffrattometro di raggi X su polvere (XRPD), introducendo corindone (Al2O3) come standard interno per la quantitativa. Non sono stati però rivelati minerali dell‟As, per via della loro scarsa concentrazione. Anche a questo proposito, sono in atto procedure di estrazione sequenziale (metodo Wenzel), per valutare la maggiore o minore mobilità dell‟As, ma pure ottenere informazioni complementari circa i minerali dell‟As presenti (ad esempio è stato individuato pentossido di As in un campione di Scarlino). Ulteriori dati circa la distribuzione dell‟As nei suoli vengono ottenuti per mezzo di una microfluorescenza di raggi X (ED-μXRF), effettuando scansioni dei suoli in sezione sottile. La biodisponibilità viene valutata utilizzando lombrichi epigeici della specie Eisenia andrei (Bouché), esposti a microcosmi contaminati e sottoposti ad analisi dei fluidi celomatici mediante TXRF e della distribuzione dell‟elemento nel corpo mediante ED-μXRF.

Plants have evolved two different strategies (Strategy I and II) to cope with Fe shortage, based on the exudation of organic and inorganic compounds to favor its mobilization and the root uptake. The role of the soil biotic component in the nutritional processes in the rhiszophere needs to be elucidated, since plants inoculated with PGPR showed an increased content of nutrients and a stronger resistance to abiotic stresses. The aim of the present work is the evaluation of the physiological effects, induced by Azospirillum brasilense in a calcareous soil on cucumber plants. Plants were grown in hydroponic Fe deficient solution followed by a 7-day period of contact with the A. brasilense-inoculated calcareous soil. At sampling, biometrics measurements, quali-quantitative analyses of root exudates and analyses of the nutrients content in plant tissues were carried out. Variations in soil mineralogy were assessed by X-ray powder diffraction (XRPD). Our results showed that A. brasilense facilitates plant growth in calcareous soils due to an enhanced recovery from the micronutrient deficiency. A. brasilense increases most likely the Fe availability within the rhizosphere by a) affecting the solubilisation of Fe thanks to the siderophore release and b) up and down-regulating the exudation activity of plants with an effect also on its molecular complexity. Further studies are needed to better understand and highlight the interactions between these two mechanisms and microorganisms. In particular, the present study shed light for the first time on two AAs, namely Gly and Glu, which could be involved in the plant-microorganism-soil interaction for the retrieval of Fe within a calcareous soil. XRPD analysis revealed a slight decrease of calcite and an increase of smectite under Fe-deficiency conditions.

Root exudates such as low molecular weight organic acids (e.g. citric acid, malic acid, oxalic acid), phenolic compounds (e.g., flavonoids), and siderophores of microbial or plant origin can alter soil mineralogy in the rhizosphere thereby releasing trace elements in solution, which can act as essential micronutrients or dangerous pollutants for plants. This research assesses the effect of various root exudates (citric acid, malic acid, oxalic acid, genistein, quercetin and siderophores) on the mineralogy of two different soils (an agricultural calcareous soil and an acidic polluted soil) and evaluates possible synergic or competitive behaviors. X-ray diffraction (XRD) coupled with Electron Probe Micro Analysis (EPMA) was used to identify the crystalline and amorphous phases which were subjected to mineral alteration when exposed to the action of root exudates. Solubilization of trace metals such as Cu, Zn, Ni, Cr, Pb, Cd as well as of major elements such as Si, Al, Fe and Mn was assessed by means of Inductively Coupled Plasma Optical Emission Spectroscopy (ICPOES). It was also found that soil microorganisms attenuated mineral weathering by reducing the concentration of active root exudates in solution. This information is an important cornerstone to better understand the biogeochemical processes acting in the rhizosphere which can play an important role in the availability of trace elements (either nutrient or toxic) for plant acquisition. Research supported by MIUR – FIRB “Futuro in ricerca” (RBFR08L2ZT), internal grant of Unibz (TN5031) and Provincia BZ Rhizotyr TN5218.

Clay minerals are phyllosilicates originating from the weathering of primary silicates and aluminosilicates. Their importance in agricultural and environmental sciences is due to their physical and chemical properties, such as their capability to retain water, ions, pollutants and organic molecules in their lattice structure. Usually, a large amount of soil is needed to extract a sufficient amount of clay minerals for their study and characterisation. In addition, long and elaborate procedures are normally employed to extract soil minerals from soil, requiring in some cases several weeks. After extraction, chemical analyses are usually performed using ICP-OES or WDXRF spectroscopies, which require 1-5 g of sample for digestion or bead/pellet production, respectively. Both these procedures need a time-consuming and elaborate processing of samples, and the use of expensive and dangerous chemicals in the case of acid digestion. Moreover, in the case of specific applications such as clay micro-synthesis, bacteria-mediated clay synthesis and remediation or sorption studies, the production of a sufficient amount of sample is often a critical issue. In these cases, chemical analysis is usually performed by Scanning Electron Microscopy coupled to microanalysis (SEM-EDS) which, besides requiring the use of a complex and expensive instrumentation, cannot provide information about the bulk sample composition. In the last two decades, total-reflection X-ray fluorescence spectroscopy (TXRF) has proven to be a sensitive and fast technique for the elemental analysis of several types of matrices (both organic and inorganic), requiring only a low amount of sample (few mg) and a simple sample preparation. In this work, a simple, fast, green and reliable method for the elemental analysis of clays employing TXRF is proposed. Clays are directly analysed by TXRF as suspensions deposited by a micropipette on sample carriers (reflectors). The method has been optimized using a two level full factorial design, to obtain the best recovery rate for each investigated element. Selenium (Se) was employed as internal standard. In particular, the following factors have been evaluated: sample amount, surfactant volume and reflector material. The best results were obtained by suspending 50 mg of clay in 2.50 ml of surfactant and using quartz reflectors. The optimized method has been subjected to in-house validation to evaluate analytical performances such as linearity, quantification limits, trueness and precision. The validation study included the analysis of certified reference materials (SARM-CRPG-CNRS). Satisfactory performances were obtained for most of the major elements including Mg, Al, Si, K, Ca, Ti, Mn and Fe and some minor elements (Cl, Ni, Zn, Ga, Rb, Sr and Pb).

The consumer demand for healthy environmentally friendly food products has today become a very high priority. Fruit and vegetable production is one of the most important in the Italian agri-food system, thus it needs to assure high quality products. The majority of elements that make up a plant, except for carbon and oxygen, are obtained from soil through the roots. Thus, the elemental composition of a tissue, i.e. the ionome, is mainly a consequence of plant-soil environment interactions. This study examined whether different soil management practices generated different metabolomic and ionomic profiles in peach fruit as assessed through HPLC/MS and TXRF analyses. Fruits (30 per treatment) were sampled at harvest from sustainable orchards (e.g. no-tillage, mulching of pruning residues, calculated irrigation, compost supply and cover crops) receiving a total of about 8 t ha-1 carbon per year, and from conventional orchards (soil tillage, burning of pruning residues, mineral fertilization, empirical irrigation). Preliminary results show that the management options impacted the metabolomic and ionomic profiles of fruit. Particularly, in fruit picked at the sustainable orchard, the content of certain key metabolites for human health and food industry were higher than that in conventional fruit (e.g. +5% for quinic acid and derivatives, +30% for gluconic acid and +15% for amygdalin). Similarly, the ionomic profile of fruit was differentiated by the orchard management highlighting that some mineral elements (e.g. Mn, Ni, Cu and Zn) could be associated to the different management options. The identification of ionomic and metabolomic profile of fruit seems to be a promising approach that could be used for characterization of an environmentally friendly product being conceivably supportive for the implementation of quality product certification strategy.

Arsenic (As) is a metalloid often associated to mining and industrial sites and its presence can cause health problems to living organisms and human beings. In order to assess As bioavailability in soils, tests which use earthworms as sentinel organisms are usually done. The evaluation of As concentration in the earthworm is commonly done after the whole digestion of the organism, which can lead to the overestimation of the concentration due to the possible presence of soil residues in the intestine. However, As is mainly accumulated by earthworms in the coelomic cavity , in particular in the coelomic fluid. This fluid can be easily extracted without killing the organism and analysed. Due to its small amount (less than 100 microliters), total x-ray fluorescence spectroscopy (TXRF) has demonstrated to be a powerful method for As detection in coelomic fluid extracts [1]. For these reasons, the present work aims at developing a new method to assess As bioavailability in contaminated soils by analyzing the As concentration in coelomic fluid extracts with TXRF. Six natural As polluted soils and two control soils were characterized by XRPD and WDXRF, while the As mobility was assessed by a sequential extraction procedure. Then, 10 sexually mature earthworms were exposed to each soil for 14 days. The elemental distribution inside the earthworm was studied by μXRF on thin sections, which localized As only in the coelomic cavity. After 24h without nourishment, three earthworms per soil were washed with distilled water and coelomic fluid extracts were collected from each of them applying a voltage of 5 V for 3 seconds. Ten microliters of extract were mixed with 80 µl of PVA and 10 µl of Y standard solution (10 mg/l). In order to compare the As concentration in the coelomic fluid extracts with the As concentration in the earthworm body, additional three earthworms per soil were depurated, dryed at 60 °C and pulverized. Slurry suspensionswere prepared using 100 mg of powder, 5 ml of Triton X-100 and 10 µl of Y standard solution (1000 mg/l). In both cases, 10 µl of sample were pipetted onto a quartz reflector and were left drying at 50 °C. TXRF analysis were performed with a S2 Picofox spectrometer (Bruker) using an acquisition time of 1000 s. Results revealed that As (both in fluids and whole bodies) increased with increasing mobile As in the soil. hHowever, As saturation (in both fluid and body) was observed when the mobile As fraction exceeded 200 mg/kg. Finally, the As concentration in coelomic fluids was positively correlated with that in the whole body. These results show that TXRF is a powerful tool to determine As concentration in earthworm coelomic fluids and that it can be used for As bioavailbility studies in soils. [1] I. Allegretta, C. Porfido, O. Panzarino, M.C. Fontanella, G.M. Beone, M. Spagnuolo, R. Terzano, Spectrochimica Acta Part B 130, 2017, 21-25.

Hexavalent chromium (Cr(VI)) is one of the most dangerous metals in polluted soils because of its carcinogenicity and high bioavailability. Conversely, its reduced form Cr(III) is low-toxic and very stable in the soil, since it occurs mainly as precipitated hydroxides. Different strategies can be adopted to remediate Cr(VI)-polluted soils and, among these, solidification/stabilization (S/S) is very efficient, being usually a cost-effective and rapid technology. It consists on the soil treatment with materials or reagents able to decrease the solubility and toxicity of heavy metals and/or entrap them in stable solid phases. In this study, glass and aluminium recycled from municipal solid wastes were used to treat, under alkaline hydrothermal conditions, a Cr(VI)-spiked soil with the aim of reducing Cr(VI) to Cr(III) and immobilizing Cr(III) in insoluble newly formed solid structures. A sandy soil was spiked with a solution of Cr(VI) to obtain, after 3 months of aging, a stable concentration of 580 mg kg-1. The soil was then added with a mixture (MIX) of pulverized glass and aluminium (1/10 and 1/20 MIX/soil, w/w). The samples were then added with KOH and deionised water (1:2 w/v), and stored at 90°C in closed HDPE bottles. Two controls without MIX, one containing KOH and the other with water alone, were also prepared. After 1, 7, 30, 60 and 90 days, soil aliquots were sampled and analyzed for Cr(VI) concentration (methods USEPA 3060A and 7196A) and Cr fractionation (BCR sequential extractions). Chromium stabilization was further investigated by analyzing the soil samples for elemental distribution (micro X-ray fluorescence – μXRF), mineralogical composition (X-ray powder diffraction – XRPD), and 3D structure of the solid phases of new formation (high resolution micro X-ray computed tomography - μCT). The reduction of Cr(VI) to Cr(III) was accelerated and intensified by the S/S treatment. In fact, about 98% Cr(VI) was reduced in only 7 days of treatment with MIX 1/20. To obtain a similar result, 30 days of treatment with MIX 1/10 and 90 days with KOH alone were needed. Prolonging the S/S process, Cr(VI) concentration was further decreased proving that Cr(III), once reduced, is not re-oxidised. Chromium mobility decreased considerably and continuously during the treatment with MIX. After 7 days, the amount of Cr associated to the more recalcitrant soil fractions was higher than 85% in the presence of MIX (at both ratios), and equal to 55% and 38% in the controls with KOH and water, respectively. Soil structure was significantly modified by the alkaline hydrothermal treatment, as proved by the formation of large soil aggregates containing Cr along with Si and Al. In fact, the addition of MIX, enriching the soil with Si and Al, accelerated the formation of soil aggregates characterized by a high micro-porosity, as revealed by μCT analysis. In most of the samples, XRPD analysis revealed the formation of a K-zeolite (edingtonite) and a strong decrease of quartz and illite. However, the stabilization of Cr was not related to zeolite formation. The innovative S/S treatment tested in this study efficiently reduces Cr(VI) to Cr(III) in the soil and stabilises Cr in newly formed soil aggregates. Scanning electron microscopy analysis of soil aggregates is also going to be performed to better understand the mechanisms of Cr stabilization within the aggregates.

La valutazione ecotossicologica e uno degli argomenti di discussione e approfondimento piu attuali nel mondo scientifico in previsione di una piu accurata determinazione dei limiti di sostenibilita dell’inquinamento ambientale. Fino ad oggi, gli studi a riguardo sono stati condotti principalmente su lombrichi, crostacei, mitili e lumache, mentre solo poche specie di insetto sono state utilizzate a questo scopo. Il presente contributo vuole fornire i risultati preliminari del saggio di determinazione delle metallotioneine applicato su Bombyx mori L. (Lepidoptera: Bombycidae) e su Galleria mellonella L. (Lepidoptera: Pyralidae). Il baco da seta e la tarma della cera sono stati utilizzati come modelli in quanto di facile manipolazione e gestione in laboratorio. L’indagine ha lo scopo di comparare le risposte di un biomarker di esposizione (metallotioneine) al rilievo di un metallo pesante (cadmio), avendo l’intento di estendere tale esperienza ad altri biomarkers, su altre specie di insetto e in condizioni naturali. Il baco e la tarma sono stati sottoposti a una dieta artificiale specifica per consentire il loro regolare sviluppo larvale. L’alimento e stato contaminato con acetato di cadmio per disporre di due tesi a differente concentrazione in cadmio: 10 e 100 ug.g-1. Per ogni trattamento e per il testimone sono state allestite tre repliche. Sei larve di B. mori di IV eta e sei larve di G. mellonella di V eta per replica sono state esposte per 5 e 6 giorni rispettivamente, a 29+-1C e 60+-5% U.R., alle tesi previste. Al termine dell’esposizione, gli individui sono stati avviati alla determinazione delle metallotioneine. Le larve di B. mori si sono mantenute vitali fino al termine della prova e il contenuto di metallotioneine e stato significativamente maggiore nei trattati con 10 ug g-1 di Cd (14,4 +- 8,5 nmol/mL) e con 100 ug g-1 di Cd (19,4 +- 0,5 nmol/mL) rispetto al controllo (2,3 +- 0,2 nmol/mL); anche le larve di G. mellonella si sono mantenute vitali fino al termine della prova e sono state apprezzate variazioni significative nel contenuto di metallotioneine tra i trattati con 10 ug g-1 di Cd (19,9 +- 1,8 nmol/mL) e con 100 ug g-1 di Cd (20,4 +- 2,4 nmol/mL) ed il controllo (12,1 +- 1,7 nmol/mL). Pertanto, la sensibilita al Cd da parte delle popolazioni delle due specie di insetto saggiate e stata simile. Una variazione significativa del contenuto di metallotioneine si e osservata in entrambe le tesi inquinate rispetto al controllo mentre l’effetto dose dipendenza tra le due tesi e risultato statisticamente non significativo.

The study of trace elements in the environment requires sophisticated analytical techniques capable of probing the samples from the field scale to the microscopic scale. In addition, environmental samples can have very different aggregation states and compositions, and therefore highly versatile analytical procedures are desirable. X-ray based analytical techniques are suitable to address both these needs being very flexible for the analysis of all kind of samples (liquids, suspensions, solids, powders, living organisms, thin samples, etc.) at different length scales (from bulk to nanometer scale). Furthermore, X-ray analyses can provide different types of information (chemical, morphological, structural) which can be finally combined together for a more comprehensive view of specific environmental issues. Limited sample preparation and non destructivity are other two key characteristics which make X-ray analyses very effective for environmental applications. However, most often this type of instrumentation is dedicated to sectoral investigations and combining different techniques requires the involvement of a number of laboratories and analytical expertises. Within this context, a team of experts in different fields of X-ray analysis at the University of Bari has created a laboratory where different X-ray analytical techniques and expertises are available in a single place for several environmental applications. In particular, the following laboratory instrumentation is available: X-ray powder diffraction (XRPD), portable X-ray fluorescence (pXRF, for field studies), wavelength dispersive X-ray fluorescence (WDXRF), energy dispersive x-ray fluorescence (EDXRF), total reflection X-ray fluorescence (TXRF), micro X-ray fluorescence (μXRF), high resolution computed X-ray tomography (HRCT) and field emission scanning electron microscopy coupled with energy dispersive X-ray microanalysis (FESEM-EDX). Long experience with synchrotron X-ray analyses and connections with the main European synchrotron facilities also allows the team to perform advanced experiments with combined synchrotron X-ray techniques. All the information coming from both laboratory and synchrotron analyses, together with routine chemical-physical approaches, can be then combined to solve complex scientific problems related to trace elements in the environment. An overview of the techniques available at Micro X-ray Lab will be presented together with some applications in the field of soil, plant and Earth sciences.

Chemical, microstructural and mineralogical studies of minerals and materials require sophisticated analytical techniques capable of probing the samples down to the nanometer scale. In addition, since this type of sample materials can have very different chemical and physical characteristics, highly versatile analytical procedures are needed. X-ray based analytical techniques are suitable to address both these needs being capable of analysing all kind of samples (solids, liquids, suspensions, powders, thin films, etc.) at different length scales (from bulk to nanometer scale). Furthermore, X-ray analyses can provide different types of information (chemical, morphological, structural) which can be finally combined for a more comprehensive view of specific issues. Limited sample preparation and non destructivity are other two key characteristics which make X-ray analyses very effective for material science studies. However, most often this type of instrumentation is dedicated to sectorial investigations and combining different techniques requires the involvement of a number of laboratories and expertise. Within this context, a team of experts in different research fields from the University "Aldo Moro" and Polytechnic University of Bari has created the “Micro X-ray Lab”: a laboratory where different X-ray analytical techniques and expertises are available in a single place for several applications. In particular, the following laboratory instrumentation is available: powder X-ray diffraction (XRD), portable X-ray fluorescence (pXRF, for field studies), wavelength dispersive X-ray fluorescence (WDXRF), energy dispersive x-ray fluorescence (EDXRF), total reflection X-ray fluorescence (TXRF), micro X-ray fluorescence (μXRF), high resolution computed X-ray tomography (HRCT) and field emission scanning electron microscopy coupled with energy dispersive X-ray microanalysis (FESEM-EDX). Long experience with synchrotron X-ray analyses and connections with the main European synchrotron facilities also allows the team to perform advanced experiments with combined synchrotron X-ray techniques. All the information coming from both laboratory and synchrotron analyses, together with routine chemical-physical approaches, can be then combined to solve complex scientific problems related to Earth and material science. An overview of the techniques available at Micro X-ray Lab will be presented together with some applications in Earth and material sciences.