Sequential solidification/stabilization and thermal process under vacuum for the treatment of mercury in sediments

Purpose  

Millions of cubic meters of sediments are dredged every year in the world. About 10–20% on weight basis of this material is contaminated by organic and/or inorganic pollutants. This work presents the laboratory tests performed to study a system for the remediation and reuse of mercury-contaminated sediments. The treatment is based on a cement-based granulation step (solidification/stabilization (S/S)), followed by a thermal process under vacuum during which volatile and semi-volatile compounds are removed. The experiments focused on: (1) cement hydration reactions; (2) pollutant removal efficiencies; and (3) leaching behavior, in relation to temperature and duration of the thermal process. Mercury speciation was also investigated.     

Fungitoxic metabolites from Erigeron apiculatus

Four enyne derivatives (1-4) and quercitrin were isolated during a bioassay-guided chromatographic separation of a methanolic extract of Erigeron apiculatus. Matricarialactone (1) and lachnophyllumlactone (2) showed a high fungitoxic activity against Pyricularia oryzae. Matricaria acid methyl ester (3) and lachnophyllum acid methyl ester (4) were, instead, less active.     

Heterogeneity of linear forest formations: differing potential for biodiversity conservation. A case study in Italy

Trees outside forests (TOF) are important elements of the landscape and they supply goods and environmental services such as commercial production of timber and fibre, domestic production of food and firewood, carbon sequestration, conservation of habitats and species (plants and animals), erosion control and soil and water quality improvement. TOF include different types of landscape elements: small woodlands, trees along linear features such as property boundaries, roads, railways, rivers and canals, hedgerows or linear forest formations, groups of trees and isolated scattered trees, which have also different ecological functions. The article focuses on the importance and role of linear forest formations (LFF) in the rural context, with special reference to the biodiversity conservation function. It presents the results of research done in the Veneto region, north-eastern Italy. The authors have designed a sampling scheme for LFF based on the Italian National Forest Inventory and tested an indicator system in order to evaluate the quality and biodiversity of the LFF. The indicators used are: LFF type and tree species composition, vertical structure and canopy cover, naturalness, introduced species and deadwood (standing and lying). The main advantages and limitations of the applied method are discussed.     

Determination of carboxylic acids in vinegars and in Aceto Balsamico Tradizionale di Modena by HPLC and GC methods

The presence of carboxylic acids in grape products has been investigated for a long time by researchers, from both the qualitative and quantitative points of view. Evaluation of carboxylic acids requires the study and optimization of some operative variables which are strictly related to the matrix. In particular, the determination of organic acids in real matrixes such as Aceto Balsamico Tradizionale of Modena (ABTM; a traditional balsamic vinegar made from cooked grape must) is often difficult because of the presence of numerous interferences that need to be removed by separation techniques. To this aim, in the present work a solid-phase extraction (SPE) method with C18 and NH(2) exchangers was used to clean the ABTM samples prior to analysis or further treatments. Both HPLC and GC techniques were used to determine organic acids. The efficiency of these two different analytical techniques in the study of ABTM acidic composition has been evaluated. Both methods separately were not able to supply all the data related to carboxylic acids. In particular, HPLC allows acetic and lactic acids quantification, but gluconic and succinic acids are better determined by GC. As far as tartaric, citric, and malic acids are concerned, both HPLC and GC methods give statistically equivalent results. The variation of the single acidic species composition along a series of casks furnished interesting information regarding the chemical transformations taking place during the aging process of this product.     

In vitro modulation of caprine monocyte immune functions by ω-3 polyunsaturated fatty acids

The in vitro effects of the ω-3 polyunsaturated fatty acids (PUFAs) eicosapentanoic acid (EPA) and docosahexanoic acid (DHA) on phagocytosis and the extracellular respiratory burst in caprine monocytes were assessed. Blood monocytes incubated with increasing concentrations of EPA or DHA (25–200 μM) demonstrated increased phagocytosis compared to unexposed monocytes. Generation of reactive oxygen species (ROS) was not markedly affected in the presence of EPA and DHA, except at 200 μM, at which concentrations monocyte viability was also reduced.     

Changes in enzymes involved in photosynthesis and other metabolic processes in the fruit of Opuntia ficus-indica during growth and ripening

The aim of this study was to investigate changes in the abundance of a number of enzymes in the peel, core and seeds of fruits of Opuntia ficus-indica (L.) Miller during development. The enzymes studied were phosphoenolpyruvate carboxylase (PEPC; EC: 4.1.1.31), ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO; EC: 4.1.1.39), aldolase (EC: 4.1.2.13), pyruvate, orthophosphate dikinase (PPDK; EC: 2.7.9.1), phosphoenolpyruvate carboxykinase (PEPCK; EC: 4.1.1.49) and aspartate aminotransferase (AspAT; EC: 2.6.1.1). To detect these enzymes, antibodies specific for each enzyme were used to probe Western blots of sodium dodecyl sulphate polyacrylamide gels. Fruit weight increased throughout development, and during ripening there was both an accumulation of total soluble solids and a decrease in both total titratable acidity and chlorophyll content. In the early stages of its growth the polypeptide pattern and enzyme composition of the fruit chlorenchyma was similar to that of the cladode. In the peel of the fruit PEPC, RUBISCO, plastidic aldolase and PPDK decreased to undetectable amounts as ripening progressed. PEPCK was not detected in either the chlorenchyma of the fruit or cladode. This showed that O. ficus-indica is not a PEPCK type CAM plant and that in this fruit PEPCK is not involved in the metabolism of organic acids. Cytosolic aldolase and AspAT were present in both the peel and core throughout development. The seeds accumulated storage proteins before the fruit ripened, and the abundance of all the enzymes studied declined once the accumulation of storage proteins was complete.     

Evaluation of resistance to Pseudomonas solanacearum in potato under controlled conditions

Summary Potato plantlets derived from in vitro propagation of three cultivars known for their field resistance (Cruza 148 and BR-63.65) or susceptibility (Désirée) to Pseudomonas solanacearum E.F. Smith were artificially inoculated under controlled conditions. The aim of this work was to determine the optimal inoculum concentration and the best observation period in which the cultivars would show different reactions to bacterial infection as expected on the basis of their field performance.A suitable statistical analysis of disease indices is proposed to distinguish between resistant and susceptible responses, with a particular care for the applicative needs and a univocal interpretation of the results. In order to evaluate the significance of sources of variation related to the observed mean differences, the analysis of variance and a convenient clustering procedure of disease index means were applied.The statistical analysis revealed that, under our conditions, an inoculum concentration of 5×10⁶ cfu/plant was suitable for separating resistant from susceptible responses, in accordance with the reactions already observed in field experiments by other authors. Also, differences among the three cultivars were best observed nine to twelve days after inoculation with the pathogen.     

Mineralisation of Surfactants Using Ultrasound and the Advanced Fenton Process

The destruction of the surfactants, sodium dodecylbenzene sulfonate (DBS) and dodecyl pyridinium chloride (DPC), using an advanced oxidation process is described. The use of zero valent iron (ZVI) and hydrogen peroxide at pH = 2.5 (the advanced Fenton process), with and without, the application of 20 kHz ultrasound leads to extensive mineralisation of both materials as determined by total organic carbon (TOC) measurements. For DBS, merely stirring with ZVI and H₂O₂ at 20°C leads to a 51% decrease in TOC, but using 20 kHz ultrasound at 40°C, maintaining the pH at 2.5 throughout and adding extra amounts of ZVI and H₂O₂ during the degradation, then the extent of mineralisation of DBS is substantially increased to 93%. A similar result is seen for DPC where virtually no degradation occurs at 20°C, but if extra amounts of both ZVI and hydrogen peroxide are introduced during the reaction at 40°C and the pH is maintained at 2.5, then an 87% mineralisation of DPC is obtained. The slow latent remediation of both surfactants and the mechanism of degradation are also discussed.