Stabilization of lead and copper contaminated firing range soil using calcined oyster shells and fly ash

A stabilization/solidification treatment scheme was devised to stabilize Pb and Cu contaminated soil from a firing range using renewable waste resources as additives, namely waste oyster shells (WOS) and fly ash (FA). The WOS, serving as the primary stabilizing agent, was pre-treated at a high temperature to activate quicklime from calcite. Class C FA was used as a secondary additive along with the calcined oyster shells (COS). The effectiveness of the treatment was evaluated by means of the toxicity characteristic leaching procedure (TCLP) and the 0.1 M HCl extraction tests following a curing period of 28 days. The combined treatment with 10 wt% COS and 5 wt% FA cause a significant reduction in Pb (>98 %) and Cu (>96 %) leachability which was indicated by the results from both extraction tests (TCLP and 0.1 M HCl). Scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDX) analyses are used to investigate the mechanism responsible for Pb and Cu stabilization. SEM–EDX results indicate that effective Pb and Cu immobilization using the combined COS–FA treatment is most probably associated with ettringite and pozzolanic reaction products. The treatment results suggest that the combined COS–FA treatment is a cost effective method for the stabilization of firing range soil.     

Changes in glucose uptake rate and in the energy status of PC-12 cells acutely exposed to hexavalent chromium,an established human carcinogen

In the 1920s, Otto Warburg reported a striking metabolic shift in solid tumors: contrary to their normal counter parts, which exhibited a nearly pure respiratory metabolism, where cancer cells relied strongly on lactic fermentation for energy production, even in the presence of ample oxygen. This metabolic shift, later named the Warburg effect, is now viewed as a nearly universal cancer phenotype. To investigate whether it is operating in hexavalent chromium (Cr(VI))-induced carcinogenesis, PC-12 cells were exposed to low Cr(VI) concentrations and effects determined on the rates of glucose uptake, lactate production and oxygen consumption, critical indicators of the type of energy metabolism adopted by the cells. Further, the influence on the cells’ energy charge, an important parameter in the evaluation of the cellular physiological state was assessed. In the presence of ample oxygen, concentration-dependent, statistically significant decreases in the energy charge were detected, which were accompanied by an increased glucose uptake rate. This enhanced uptake may constitute the first step in a compensatory mechanism aimed at counteracting the decrease in energy charge. Although these changes may be too small to exert an impact in the cellular functions, they may provide insight into the initial steps of Cr(VI)-induced carcinogenesis.     

Anaerobic decolorization of an azo dye by a mixed culture

Wool dyeing wastewater contains xenobiotic compounds that can be removed by biotechnological processes. Studies on various dyes showed that anaerobic processes are suitable to alter azo dyes as a first step of the biodegradation process. These compounds are reduced by anaerobic consortia to aromatic amines and its ultimate degradation can be achieved by a further aerobic treatment.

Studies on degradation rate of an wool acid dye were performed in batch systems inoculated with anaerobic biomass. A commercial diazo dye, Acid Red 73, was added to the synthetic medium in which glucose was used as sole carbon source.

Results indicated that the Acid Red 73 was partially degraded by a mixed culture of anaerobic bacteria and a decolorization of 90% was obtained. Kinetics studies on removal of the colour showed that the decolorization rate was several times faster than the degradation rate of glucose for a range of dye concentrations between 60 mg/L and 400 mg/L. A first order kinetic model was used for dye concentrations up to 200 mg/L. For higher concentrations a model similar to the Michaelis‐Menten equation was better fitted to the experimental data.     

Green fuel production: processes applied to microalgae

The continuous increase in world energy demand will lead to an energy crisis due to the limited availability of fossil fuels. Furthermore, the use of this energetic resource is responsible for the accumulation of greenhouse gases in atmosphere that is associated with several negative effects on environment. Therefore, it is worth to search for different energy supplies that are renewable and environmentally friendly—carbon neutral fuel. Microalgae are photosynthetic microorganisms that can achieve high oil contents. This oil is suitable for producing biodiesel; thus, microalgae are considered a promising sustainable energetic resource that can reduce the dependence on fossil fuel. Biodiesel production from microalgae includes several steps, such as cell cultivation and harvesting, oil extraction and biodiesel synthesis. Although several attempts have been made to improve biodiesel yields from microalgae, further studies are required to improve biodiesel production rates and to reduce the associated costs. This review shows the recent developments on biodiesel production from microalgae, emphasizing two process concepts: (1) indirect route, in which, after a facultative cell wall disruption method, microalgal oil is recovered in an appropriate solvent and then converted into biodiesel through transesterification and (2) direct route, in which biodiesel is produced directly from the harvested biomass. High biodiesel yields are obtained when both routes are preceded by a cell wall disruption method. In the indirect route, it is possible to apply three different types of solvents to recover microalgal oil. Although there are several concerns about the application of organic solvents, the most promising and cost-effective alternative for lipid recovery is n-hexane. Comparing direct and indirect routes, this study demonstrates that although further studies are required to optimize biodiesel production from microalgae, the available information proposes that the direct route is the most efficient.     

Genotoxic Effect of Phenol on the Cells of Onion (Allium cepa) Roots

The roots of onion (Allium cepa) stand out for having cells with large size and small number of chromosomes.These characteristics make them useful in bioassays for the measurement of a variety of cytogenetic and morphological parameters , in which they can be used as toxicity indicators of the induction and formation of micronuclei and chromosomal aberrations.Based on this background , the potential genotoxic effect of phenol concentration on cells of A.ceparoots was investigated either in terms of induced aberrations or micronuclei formation.The results demonstrated that the higher the concentration of phenol , the higher the incidence of abnormalities , thus confirming the genotoxicity of this pollutant.     

Nonapeptide levels in male cleaner fish brains during interactions with unfamiliar intra and interspecific partners

Behavioral Ecology and Sociobiology - A growing body of research suggests that songs are an important part of the courtship behavior of many bat species, however there is little information on the...     

Who’s what? Prompt recognition of social status in crayfish

Crayfish are excellent model organisms to study the proximate mechanisms underlying the maintenance of dominance hierarchies in invertebrates. Our aim here was to investigate whether Procambarus clarkii males use social eavesdropping to discriminate dominant from subordinate crayfish. To this end, we conducted an experiment composed of a “passive” and an “active” phase. In the passive phase, “focal” individuals were allowed (treatment 1) or not (treatment 2) to see and smell two size-matched crayfish fighting while, in the subsequent active phase, they were allowed to freely interact with the fighting dyad. None of the recorded variables showed any significant difference between the two treatments, but, invariably, focal individuals were able to promptly discriminate dominant from subordinate crayfish. This study provides evidence that male crayfish recognize the social status of a conspecific without the need of direct or indirect experience with it and avoid dominants—and thus dangerous opponents—by means of a badge of status. A form of “winner and loser effects” could also contribute to the structuring of dominance/subordinate relationships. The implication of these results in understanding the maintenance of dominance hierarchies in invertebrates are discussed and compared with findings previously achieved in the context of mate choice by P. clarkii females, who do appear to use eavesdropping to identify dominants and subordinates.     

Decline in extractable antibiotics in manure-based composts during composting

A wide variety of antibiotics have been detected in natural water samples and this is of potential concern because of the adverse environmental effects of such antibiotic residues. One of the main sources of antibiotics effluence to the surrounding environment is livestock manures which often contain elevated concentrations of veterinary antibiotics (VAs) which survive digestion in the animal stomach following application in animal husbandry practices. In Korea, livestock manures are normally used for compost production indicating that there is potential for antibiotic release to the environment through compost application to agricultural lands. Therefore, reduction of the amount of VAs in composts is crucial. The purpose of this study was to understand the influence of the composting process and the components of the compost on the levels of three common classes of antibiotics (tetracyclines, sulfonamides, and macrolides). Composted materials at different stages of composting were collected from compost manufacturing plants and the variation in antibiotic concentrations was determined. Three different antibiotics, chlortetracycline (CTC), sulfamethazine (SMZ), and tylosin (TYL) at three different concentrations (2, 10, and 20 mg kg⁻¹) were also applied to a mixture of pig manure and sawdust and the mixtures incubated using a laboratory scale composting apparatus to monitor the changes in antibiotic concentrations during composting together with the physicochemical properties of the composts. During composting, in both field and lab-scale investigations, the concentrations of all three different antibiotics declined below the relevant Korean guideline values (0.8 mg kg⁻¹ for tetracyclines, 0.2 mg kg⁻¹ for sulfonamides and 1.0 mg kg⁻¹ for macrolides). The decline of tetracycline and sulfonamide concentrations was highly dependent on the presence of sawdust while there was no influence of sawdust on TYL decline.     

Preparation of CuO/SiO<Subscript>2</Subscript> and photocatalytic activity by degradation of methylene blue

A photocatalyst based on CuO/SiO₂ was prepared, and evaluated for the degradation of methylene blue in aqueous medium. The photocatalyst was obtained by calcination method of copper salt, in the presence of silica. The characterization by XRD, FTIR, and TPR techniques confirmed the formation of CuO as active phase. SEM studies showed CuO deposited on the surface of SiO₂. By ESI-MS, it was demonstrated that the degradation of methylene blue occurs through successive hydroxylations. Photodegradation assays showed that CuO/SiO₂ was efficient for degradation, and that the material worked better in the presence of UV light.     

Ecosystem services and biodiversity conservation under forestation scenarios: options to improve management in the Vez watershed,NW Portugal

Ensuring forest protection and the delivery of forest ecosystem services is a central aim of the European Union’s biodiversity strategy for 2020. Therefore, accurate modelling and mapping of ecosystem services as well as of biodiversity conservation value is an important asset in support of spatial planning and policy implementation. The objectives of this study were to analyse the provision of the multiple ecosystem services under two forestation scenarios (eucalyptus/pine vs. oak) at the watershed scale and to evaluate their possible trade-offs with the biodiversity conservation value. The Vez watershed, in northwest Portugal, was used as case study area, in which soil and water assessment tool (SWAT) was applied to simulate the provision of hydrological services, biomass and carbon storage services. Biodiversity conservation value was based on nature protection regimes and on expert judgement applied to a land cover map. Results indicated large provision of ecosystem services in the high and low mountain sub-basins. The overall performance for water quantity and timing is better under the shrubland and oak forest scenarios, when compared to the eucalyptus/pine forest scenario, which perform better for flood regulation and erosion control services, especially in the low mountain sub-basin. The current shrubland dominated cover also shows good performance for the control of soil erosion. The oak scenario is the one with less trade-offs between forest services and biodiversity conservation. Results highlight SWAT as an effective tool for modelling and mapping ecosystem services generated at the watershed scale, thereby contributing to improve the options for land management.