Heavy metals transport in typical portuguese loamy sand soils

Illegal discharges are of great concern among industry activities, since they occur under uncontrolled conditions. In most cases, effluents are acidic and the concentrations of heavy metals are very high. With this in mind, the main goal of this study was to evaluate the sorption of two of the most toxic heavy metals, Cr(VI) and Pb(II), in those conditions. A loamy sand soil was collected in Oporto, Portugal. Batch equilibrium and kinetic sorption experiments were performed using both metals solutions, with concentrations among 50 mg L-1 and 200 mg L-1, at pH 2 and 5, between 2 h and 288 h. To evaluate the sorption equilibrium, eight isotherm models were fitted. Better adjustments were observed for the Redlich-Peterson and Khan models for the adsorption of chromium (R2 = 0.99), and of lead (R2 = 0.99), respectively. The sorption kinetics was evaluated using three models – Elovich, Pseudo first order and an empirical power function. The retention of lead was almost instantaneous and the empirical power function described better the sorption kinetics of chromium (0.89 < R2 < 0.99). In addition, flow experiments were performed with effluents of both metals (50 mg L-1) at pH 2 and 5, for about 90 h. Results revealed a high retention of chromium, and a weak retention of lead, for low pH values. FTIR analyses to the columns samples revealed that clay minerals have an important role in the retention of both metals

Effect of phosphorus on the attenuation of lead and chromium

This study analyses the adsorption of Pb(II) and Cr(III) in soils. These metals are commonly found together in nature in urban wastes or industrial spillages, and the theoretical approach of the work was to evaluate the response of the soil to continuous Cr and Pb spillages to soil in terms of several physicochemical parameters. The influence of an anthropogenic input of phosphorus was evaluated. Continuous flow experiments were run in duplicates in acrylic columns (25 cm × 3.2 cm). The influent Cr(III) and Pb(II) solutions of 10 mg l−1 and 25 mg l−1 at pH 5 were pumped upward through the bottom of the columns to ensure saturation flow conditions. Also, successive experiments were run with the above concentrations of Cr(III) and Pb(II) and NaH2PO4, keeping metal to phosphorus ratio of 1:0, 1:0.1 and 1:1. Modelling parameters included Freundlich and Langmuir equations, together with the Two-site adsorption model using CXTFIT code. Results obtained allowed concluding that Pb(II) adsorption presents a certain degree of irreversibility and the continued spillages over soil increment the fraction which is not easily desorbed. Cr(III) desorption was almost complete, evidencing its high mobility in nature. The presence of an anthropogenic input of phosphorus leads to a marked increase of both Pb(II) and Cr(III) adsorption in soils. Z-potential measurements allow to discard the electrostatic attraction of Cr(III) and Pb(II) with the surface charged soil as the dominant process of metal sorption. Instead, CheaqsPro simulation allows to identify PbH2PO4 +, PbHPO4 (aq) and CrHPO4 + as the dominant species which regulate Cr(III) and Pb(II) transport in soils.Fundação para a Ciência e a Tecnologi

Adaptation and Validation of QUick, Easy, New, CHEap, and Reproducible (QUENCHER) Antioxidant Capacity Assays in Model Products Obtained from Residual Wine Pomace

Evaluation of the total antioxidant capacity of solid matrices without extraction steps is a very interesting alternative for food researchers and also for food industries. These methodologies have been denominated QUENCHER from QUick, Easy, New, CHEap, and Reproducible assays. To demonstrate and highlight the validity of QUENCHER (Q) methods, values of Q-method validation were showed for the first time, and they were tested with products of well-known different chemical properties. Furthermore, new QUENCHER assays to measure scavenging capacity against superoxide, hydroxyl, and lipid peroxyl radicals were developed. Calibration models showed good linearity (R2 > 0.995), proportionality and precision (CV < 6.5%), and acceptable detection limits (<20.4 nmol Trolox equiv). The presence of ethanol in the reaction medium gave antioxidant capacity values significantly different from those obtained with water. The dilution of samples with powdered cellulose was discouraged because possible interferences with some of the matrices analyzed may take place.The autonomous government of Castilla y León (Project BU268A11-2

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2

Assessment of phenolic herbicide toxicity and mode of action by different assays

A phytotoxicity assay based on seed germination/root elongation has been optimized and used to evaluate the toxic effects of some phenolic herbicides. The method has been improved by investigating the influence of experimental conditions. Lepidium sativum was chosen as the most suitable species, showing high germinability, good repeatability of root length measurements, and low sensitivity to seed pretreatment. DMSO was the most appropriate solvent carrier for less water-soluble compounds. Three dinitrophenols and three hydroxybenzonitriles were tested: dinoterb, DNOC, 2,4-dinitrophenol, chloroxynil, bromoxynil, and ioxynil. Toxicity was also determined using the Vibrio fischeri MicrotoxA (R) test, and a highly significant correlation was found between EC50 values obtained by the two assays. Dinoterb was the most toxic compound. The toxicity of hydroxybenzonitriles followed the order: ioxynil > bromoxynil > chloroxynil; L. sativum exhibited a slightly higher sensitivity than V. fischeri to these compounds. A QSAR analysis highlighted the importance of hydrophobic, electronic, and hydrogen-bonding interactions, in accordance with a mechanism of toxic action based on protonophoric uncoupling of oxidative phosphorylation. The results suggest that the seed germination/root elongation assay with L. sativum is a valid tool for the assessment of xenobiotic toxicity and can be recommended as part of a test battery

Comparación de la estabilidad estructural de suelos de prado y cultivo

6 páginas, 4 figuras, 2 tablas, 14 referencias. Trabajo presentado al citado Simposio, Área temática 1: Calidad vs degradación de los suelos por actividades antrópicas, celebrado del 6-7, julio, 2005, en Madrid, España.[ES]: Se comparan las propiedades estructurales de dos suelos de la zona templado-húmeda española desarrollados sobre granito, dedicados a prado permanente y cultivo, a fin de valorar el impacto del tipo de manejo sobre la calidad estructural. El suelo de prado presentó unas propiedades estructurales más favorables, tales como una menor densidad aparente y mayor porosidad, un mayor tamaño medio de agregados, y una mayor estabilidad de los agregados frente a la agitación mecánica en agua y frente a la acción de la lluvia simulada. Esta mayor estabilidad estructural del suelo de prado se relaciona con su mayor contenido de materia orgánica (MOS). Asimismo, el suelo de prado presentó una mayor actividad microbiana, según se deduce de los valores más altos de respiración en experimentos de incubación, en comparación con el suelo de cultivo. El suelo de prado también presentó los valores más elevados de cociente respiratorio (C-CO2/C orgánico total), de lo que se deduce que la MOS del suelo de prado es más accesible a la degradación microbiana. Sin embargo no se observaron diferencias significativas entre la mineralización del carbono orgánico del suelo disgregado (<1mm) y de agregados intactos del mismo suelo (5-1 mm). Los resultados de este trabajo ponen en evidencia la necesidad de mantener niveles adecuados de MOS a través de enmiendas o reducción del laboreo.[EN]: We compared the structural properties of two neighbouring soils from the NW of Spain in order to evaluate the effect of management on structural quality. The soils were developed on granite under a warm and humid climate but differed in land use (pasture and cultivation). The pasture soil had more favourable structural properties than the cultivated soil, showing lower bulk density, higher porosity and water retention, higher mean aggregate diameter and aggregate stability against mechanical agitation in air and water, as well as lower soil loss under simulated rainfall. This increased structural stability of the pasture soil could be attributed to its elevated organic matter (OM) content. More C-CO2 was also released by OM mineralization in laboratory incubated pasture soil samples than in culture soils, due to higher microbial activity. Respiratory quotient (C-CO2/Corg total) was also higher in the pasture soil, thus indicating that the OM is more accessible to microbial decomposition. Nevertheless no significant differences were observed between organic C mineralization in disturbed ground soil <1 mm and undisturbed 5-1 mm aggregates. The overall results demonstrate the need to maintain adequate levels of OM by means of organic amendments or tillage reduction.Peer reviewe