Biosorption of Reactive Black 5 from aqueous solutions by chitosan: Column studies

Fixed-bed column studies were carried out to investigate the dynamic sorption of Reactive Black 5 (RB5) onto chitosan. The effect of operating parameters such as initial dye concentration, superficial flow velocity, bed height and particle size on the sorption of RB5 onto chitosan was studied. Column regeneration, dye recovery and the possibility of reusing the regenerated chitosan were also investigated. The results show that both the breakthrough curves and the adsorption parameters of the column were strongly affected by the operating parameters studied. An analysis of the breakthrough curves indicated that adsorption was affected by mass transfer limitations, probably due to intraparticle diffusion. An empirical model was applied to describe the breakthrough curves, while the Bohart–Adams and BDST models were used to determine the operating parameters useful in the process design. Elution of the column with 0.01 mol L^?1 NaOH allowed the chitosan to be regenerated and the dye to be recovered and concentrated. The concentration factor was 10. Several cycles of adsorption–elution showed that the regenerated chitosan retained good adsorption efficiency and the elution efficiency was always higher than 80%.     

Assessing biodiversity vulnerability to climate change: testing different methodologies for Portuguese herpetofauna

Assessing biodiversity vulnerability to future climate change is essential for developing robust adaptation strategies. A number of vulnerability assessment methodologies have been developed, from bioclimatic envelop models to more complex approaches that also consider biological traits and population status. However, the lack of comparative studies leaves the user to choose among the different methodologies without much guidance. This study applied three vulnerability assessment approaches to the Portuguese herpetofauna: (I) impact assessment approach based on bioclimatic models; (II) integrated vulnerability assessment approach, adding the evaluation of adaptive capacity to approach I; and (III) integrated vulnerability assessment and validation based on expert consultation. Results showed disagreement between the different approaches for 19 % of the species studied. Most differences were found between approach III and the two other approaches. All approaches showed advantages and limitations, the choice of a methodology being ultimately dependent on the study goals. Approach I has proven efficient to capture general vulnerability patterns. Approach II, although presenting results similar to approach I, allows for the identification of key factors affecting the species adaptive capacity and may be useful in tailoring adaptation measures. Approach III further allows us to identify knowledge gaps and to evaluate vulnerability when data availability or quality is reduced. Further, because this approach is based on an expert workshop, it has proven a perfect means to build on the vulnerability assessment results to identify indicator species and prioritize specific adaptation options.     

The emergence of climate change policy entrepreneurs in urban regions

Regional Environmental Change - The development of climate change policy in cities has been closely tied to the efforts of particular individuals, policy entrepreneurs. However, there is still much...     

Direct and efficient liquefaction of potato peel into bio-oil

The world has become dependent on petroleum as a feedstock for most products that we use in our daily lives. As an alternative, bio-refineries that transform biomass into biofuels and primary chemicals are emerging. Actually, many wastes are not fully recycled. For instance, potato peel is a cheap residue available from the potato industry. Up to now, potato peel has been used mostly for livestock feeding. Here, potato peel waste was subjected to direct acid liquefaction at 160 °C in 2-ethylhexanol and diethylene glycol using p-toluene sulfonic acid as catalyst. The product was characterized by infrared spectroscopy, chemical analysis, hydroxyl number and acid value. Results show that liquefaction was achieved in yields higher than 80%. The reactional profile shows two time zones, one comprising the process of liquefaction and one corresponding to the process of decomposition. Kinetics indicate that the liquefaction process occurs 1.9 times faster than the decomposition process. Overall, our findings show for the first time that, despite the water content, potato peel waste can be used to produce bio-oil. The products can be further used as fuels or refined chemicals such as levulinic acid, furfural, 5-hydroxyfurfural, dimethyl furfural and sugars in fermentation processes.     

Composition analysis of dental solid waste in Brazil

When developing proper waste management strategies, it is essential to characterize the volume and composition of solid waste. The aim of this work was to evaluate the composition of dental waste produced by three dental health services in Belo Horizonte, Minas Gerais State, Brazil. Two universities, one public and one private, and one public dental health service were selected. Waste collection took place from March to November 2007. During this period, three samples were collected from each dental health service. The total amount of dental waste produced in one day of dental work was manually separated into three categories: infectious and potentially infectious waste, accounting for 24.3% of the total waste; non-infectious waste, accounting for 48.1%; and domestic-type waste, accounting for 27.6% (percentages are for mean weights of solid waste). Our results showed that most of the waste considered as biomedical may be misclassified, consequently making the infectious waste amount appear much larger. In addition, our results suggest that the best waste minimization method is recycling, and they help to define an appropriate waste management system in all three of the dental health services involved in this study.     

Science, Ethical Arguments, and Management in the Preservation of Land for Grizzly Bear Conservation

Abstract: Environmental groups advocate the preservation of an area within British Columbia's coastal temperate rainforest as a sanctuary for grizzly bears (    Ursus arctos horribilis ). Debate among government, industry, and environmental spokespersons has provided arguments but no resolution. We have applied to this issue available biological knowledge on grizzly bears and the arguments of a range of ethical theories. The theories of three professionally trained ethicists were included: Tom Regan, Holmes Rolston III, and Arne Naess. Aldo Leopold's prominent position in the conservation movement justifies his "land ethic" as a fourth ethical theory. All four theories agree that the area should be preserved. Contrary to this fundamental agreement, the theories diverge when tested against a "hard" conservation scenario, the conflict between the protection of the last surviving grizzly bears versus the survival of a culturally distinct human tribe. Application of the principles developed by Regan and Naess recommend that human interests should override the preservation of grizzly bears, whereas Leopold's and Rolston's arguments favor the preservation of the area for the bears. Our work can be used as a model of how the gap between biological sciences, ethical theories, and ecosystem management can be bridged successfully.     

Kill before being killed: an experimental approach supports the predator-removal hypothesis as a determinant of intraguild predation in top predators

Intraguild predation (IGP) has been explained in terms of competitor-removal, food-stress and predator-removal hypotheses. Only the first two hypotheses have been fairly well studied. To test the predator-removal hypothesis as a force determining IGP in avian predators, we performed a field experiment to simulate the presence of an IG predator (eagle owl Bubo bubo dummy) in the surrounding of the nests of four potential IG prey (black kite Milvus migrans, red kite Milvus milvus, booted eagle Aquila pennata and common buzzard Buteo buteo). To discard the possibility that an aggressive reaction towards the eagle owl was not related to the presence of the IG predator, we also presented a stuffed tawny owl Strix aluco, which is a potential competitor but cannot be considered an IG predator of the studied diurnal raptors considered in the experiment. While almost always ignoring the tawny owl, raptors chiefly showed an interspecific aggressive behaviour towards their IG predator. Our results seem to support the predator-removal hypothesis, as the IG prey may take advantage of the diurnal inactivity of the IG predator to remove it from their territory. However, the recorded behaviour may be also considered as a special variety of mobbing (i.e. a prey’s counter-strategy against its predator), where the mobber is sufficiently powerful to escalate predator harassment into deliberate killing attempts. In their turn, eagle owls can respond with an IG predatory behaviour aimed at removing IG prey species which are highly aggressive mobbers.     

Environmental–sanitary risk analysis procedure applied to artificial turf sports fields

Owing to the extensive use of artificial turfs worldwide, over the past 10 years there has been much discussion about the possible health and environmental problems originating from styrene-butadiene recycled rubber. In this paper, the authors performed a Tier 2 environmental–sanitary risk analysis on five artificial turf sports fields located in the city of Turin (Italy) with the aid of RISC4 software. Two receptors (adult player and child player) and three routes of exposure (direct contact with crumb rubber, contact with rainwater soaking the rubber mat, inhalation of dusts and gases from the artificial turf fields) were considered in the conceptual model. For all the fields and for all the routes, the cumulative carcinogenic risk proved to be lower than 10^?6 and the cumulative non-carcinogenic risk lower than 1. The outdoor inhalation of dusts and gases was the main route of exposure for both carcinogenic and non-carcinogenic substances. The results given by the inhalation pathway were compared with those of a risk assessment carried out on citizens breathing gases and dusts from traffic emissions every day in Turin. For both classes of substances and for both receptors, the inhalation of atmospheric dusts and gases from vehicular traffic gave risk values of one order of magnitude higher than those due to playing soccer on an artificial field.     

The application of the vermicomposting process in the bioremediation of diesel contaminated soils

Abstract

Polycyclic Aromatic Hydrocarbons (PAHs) are among the environmental pollutants that have very high carcinogenic and mutagenic activity. Among hundreds of different PAHs, 17 are considered priority pollutants and routinely monitored for regulatory purposes. Extended periods of exposure and expensive clean-up costs are typically associated with the vast majority of processes used for the remediation of areas contaminated with PAHs. The results of this study indicate that bioremediation via vermicomposting could be an effective method for remedying soils contaminated with toxic organic compounds, such as PAHs. This study was conducted over 90?days in the presence of various quantities of organic matter (cattle manure) to recover soils contaminated with PAHs. High-performance liquid chromatography (HPLC) was applied to identify PAHs. An evaluation of the toxicity of the final material and the transformation of the organic matter throughout the process was also conducted. The data presented here suggest a relationship between the molar mass of the PAHs and the ability of the vermicomposting process to promote biodegradation. These results suggest that vermicomposting has great potential to be utilized as a tool for the bioremediation of soils impacted by PAHs.