Investigating the evolution of fractures in clay–based ceramics during repeated freeze-thawing cycles using micro X-ray computed tomography and image analysis

Acknowledgements Ignazio Allegretta was supported by a research grant on the project PON R&I – Progetto AIM1809249 – attivitá 1, linea 1. Data Availability The raw/processed data required to reproduce these findings cannot be shared at this time as they include more than 4TB of raw micro-tomographic data. However, for those researchers interested in analysing this dataset, tomographic data will be made available upon request by contacting the Dr. Carlo Porfido (e-mail: [email protected]). The FracPaQ toolbox, used for image analysis, is freely available to download from the following addresses: http://fracpaq.com/index.html.Peer reviewedPostprin

Dry fractionation as a promising technology to reuse the physically defected legume-based gluten-free pasta

Dry fractionation was applied to the legume-based pasta (yellow lentils:whole rice 90:10 w:w) discarded for physical defects. After the air classification, the fine fraction showed a 33% increment of the protein content compared to the raw material, with a 21% yield. The scanning electron micrographs revealed the presence of protein–starch complexes and broken starch granules which led to a low protein separation efficiency. The fine fraction showed interesting nutritional features due to the high concentration of the essential micronutrients Zn (43.3 mg kg−1) and Fe (72.6 mg kg−1). However, also the alpha-galactosides were enriched into the same fraction. The two fractions, fine and coarse, were both characterised by elevated water absorption capacity, with significantly higher values in the fine one. Finally, the gelling capacity varied among the fractions, being influenced by the protein content. Overall, these ingredients could be used to fortify the protein and the essential mineral contents of bakery products, sauces, and creams

Synchrotron radiation in soil and geosciences

This special issue is the outcome of the Session SSS24 `Synchrotron radiation in soil and geosciences' that was held on 21 April 2009 in Vienna during the EGU (European Geosciences Union) General Assembly 2009, within the Soil System Sciences (SSS) program. In this special issue ten papers are presented, chosen after a selection among 19 written contributions that were received after the scientific Session at EGU

ALKALINE HYDROTHERMAL STABILIZATION OF Cr(VI) IN A SANDY SOIL

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

Investigating Lead Bioavailability in a Former Shooting Range by Soil Microanalyses and Earthworms Tests

Shooting ranges are among the major anthropogenic sources of Pb contamination in soils worldwide. Once they have reached the soil, bullet residues can have different fates according to the characteristics of the soil environment, leading to the formation of different Pb weathering products whose stability is crucial for Pb accessibility to soil biota. In this study, Pb availability in a former polluted shooting range was investigated with a combination of conventional soil analyses, X-ray microanalyses and assays with the bio-indicator earthworm Eisenia andrei. Chemical extractions evidenced a rather low mobility of soil Pb, while micro-X-ray fluorescence spectroscopy (mu XRF) and scanning electron microscopy coupled with microanalysis (SEM-EDX) showed the formation of a weathering crust around Pb-containing bullet slivers dispersed within the soil. Such crusts consisted of a mixture of orthophosphates, including the highly insoluble Cl-pyromorphite. Furthermore, no acute toxicity effects and low Pb concentration values were measured in earthworm tissues (94.9 mg kg(-1)) and coelom fluids (794 mu g L-1) after 28 days of exposure to the polluted soil. These results allow us to assume that most of the Pb in the shooting range soil underwent stabilization processes promoted by phosphatic fertilization. The soil was in fact used for agriculture after being dismissed for firing activities. Such a combined approach can be applied to study Pb bioavailability in other shooting ranges or, more generally, in soils heavily polluted with P

The fertilising potential of manure-based biogas fermentation residues: pelleted vs. liquid digestate

Spreading of manure on agricultural soils is a main source of ammonia emissions and/or nitrate leaching. It has been addressed by the European Union with the Directives 2001/81/EC and 91/676/EEC to protect the environment and the human health. The disposal of manure has therefore become an economic and environmental challenge for farmers. Thus, the conversion of manure via anaerobic digestion in a biogas plant could be a sustainable solution, having the byproducts (solid and liquid digestates) the potential to be used as fertilizers for crops. This work aimed at characterizing and assessing the effect of digestates obtained from a local biogas plant (Biogas Wipptal, Gmbh), either in the form of liquid fraction or as a solid pellet on: (i) the fertility of the soils during an incubation experiment; (ii) the plant growth and nutritional status of different species (maize and cucumber). Moreover, an extensive characterization of the pellet was performed via X-ray microanalytical techniques. The data obtained showed that both digestates exhibit a fertilizing potential for crops, depending on the plant species and the fertilizer dose: the liquid fraction increases the shoot fresh weight at low dose in cucumber, conversely, the solid pellet increases the shoot fresh weight at high dose in maize. The liquid digestate may have the advantage to release nutrients (i.e. nitrogen) more rapidly to plants, but its storage represents the main constraint (i.e. ammonia volatilization). Indeed, pelleting the digestates could improve the storability of the fertilizer besides enhancing plant nutrient availability (i.e. phosphate and potassium), plant biomass and soil biochemical quality (i.e. microbial biomass and activity). The physical structure and chemical composition of pellet digestates allow nutrients to be easily mobilized over time, representing a possible source of mineral nutrients also in long-term applications

Mercury speciation in the colloidal fraction of a soil polluted by a chlor-alkali plant: a case study in the South of Italy

Mercury (Hg) speciation in different size fractions of a soil sample collected near an industrial area located in the South of Italy, which had been polluted by the dumping of Hg-containing wastes from a chlor-alkali plant, was investigated by XANES spectroscopy. In particular, a special procedure has been developed to study the soil colloidal fraction, both for sample preparation and for XANES data collection. In this soil, Hg was speciated in quite insoluble inorganic forms such as cinnabar (alpha-HgS), metacinnabar (beta-HgS), corderoite (Hg3S2Cl2), and some amorphous Hg, S and Cl-containing species, all derived from the land-disposal of K106 Hg-containing wastes. The contribution of the above-mentioned chemical forms to Hg speciation changed as a function of particle size. For the fraction corderoite (26%) > cinnabar (20%) = metacinnabar (20%); for the fraction metacinnabar (24%) > corderoite (20%) > cinnabar (16%); and for the fraction 430-650 nm, where most of the colloidal Hg was concentrated: amorphous Hg-S-Cl (56%) > metacinnabar (33%) > corderoite (6%) > cinnabar (5%). From these data it emerged that, even if Hg was speciated in quite insoluble forms, the colloidal fraction, which is the most mobile and thus the most dangerous, was enriched in relatively more soluble species (i.e. amorphous Hg-S-Cl and metacinnabar), as compared with cinnabar. This aspect should be seriously taken into account when planning environmental risk assessment, since the small particle size in which Hg is concentrated and the changing speciation passing from millimetre to nanometre size could turn apparently safe conditions into more hazardous ones

Nutritional characterization and shelf-life of packaged microgreens

Comprehensive nutritional profile of six microgreens, including proximate composition and bioactive compounds