Modelling the Competitive Sorption Process of Multiple Solutes During their Transport in Porous Media

A general mathematical model to solve the advection–dispersion transport equation for multiple solutes was developed, where the dual porosity mobile–immobile mass transfer, the two-site non-equilibrium model and first-order transformation reactions were included. The two-site model was expressed with an equilibrium sorption term and a kinetic term. One of three kinetic models could be used: the non-linear, the bilinear and the pore diffusion model. The traditional Freundlich or Langmuir isotherms were employed to simulate no-interaction between the solutes, but with the extended Freundlich or extended Langmuir isotherms, a competitive sorption could be simulated. The transport equation was solved with the Moving Concentration Slope method. The mathematical model was tested and further simplified by using real data from soil column experiments, with 1,2-cis-dichloroethene and trichloroethene as model contaminants and silica gel and real soil samples as porous medium.     

Pathogen-induced hatching and population-specific life-history response to waterborne cues in brown trout (Salmo trutta)

Hatching is an important niche shift, and embryos in a wide range of taxa can either accelerate or delay this life-history switch in order to avoid stage-specific risks. Such behavior can occur in response to stress itself and to chemical cues that allow anticipation of stress. We studied the genetic organization of this phenotypic plasticity and tested whether there are differences among populations and across environments in order to learn more about the evolutionary potential of stress-induced hatching. As a study species, we chose the brown trout (Salmo trutta; Salmonidae). Gametes were collected from five natural populations (within one river network) and used for full-factorial in vitro fertilizations. The resulting embryos were either directly infected with Pseudomonas fluorescens or were exposed to waterborne cues from P. fluorescens-infected conspecifics. We found that direct inoculation with P. fluorescens increased embryonic mortality and induced hatching in all host populations. Exposure to waterborne cues revealed population-specific responses. We found significant additive genetic variation for hatching time, and genetic variation in trait plasticity. In conclusion, hatching is induced in response to infection and can be affected by waterborne cues of infection, but populations and families differ in their reaction to the latter.     

Gametogenesis,embryogenesis, and larval features of the oviparous sponge <Emphasis Type="Italic">Petrosia ficiformis</Emphasis> (Haplosclerida,Demospongiae)

This study describes the reproductive cycle of Petrosia ficiformis and documents for the first time embryogenesis in an oviparous haplosclerid demosponge. Gonochoric adults, occurring in 2:1 female/male ratios, spawned in late autumn, after a 7-month long oogenesis and a 2.5-week-long spermatogenesis. Following a remarkable migration, the oocytes were released as 250 μm eggs bearing attached polar bodies and a thin mucous cover. Round-headed spermatozoa with three large mitochondria, and many proacrosomal vesicles fertilized the eggs externally. A fertilization membrane appeared around the zygotes. Nearly equal and total cleavage led to a stereoblastula that subsequently became an entirely ciliated larva. The larva alternated spherical and multilobate body shape and consisted of undifferentiated cells. It had poor abilities to swim and glide, probably experiencing passive dispersal and unselective attachment. Settlers developed choanocyte chambers after 1.5 months. Symbiotic microbes were absent from gametes and larvae, being necessarily acquired from the ambient at each sponge generation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Balkanized Research in Ecological Engineering Revealed by a Bibliometric Analysis of Earthworms and Ecosystem Services

Energy crisis, climate changes, and biodiversity losses have reinforced the drive for more ecologically-based approaches for environmental management. Such approaches are characterized by the use of organisms rather than energy-consuming technologies. Although earthworms are believed to be potentially useful organisms for managing ecosystem services, there is actually no quantification of such a trend in literature. This bibliometric analysis aimed to measure the evolution of the association of “earthworms” and other terms such as ecosystem services (primary production, nutrient cycling, carbon sequestration, soil structure, and pollution remediation), “ecological engineering” or “biodiversity,” to assess their convergence or divergence through time. In this aim, we calculated the similarity index, an indicator of the paradigmatic proximity defined in applied epistemology, for each year between 1900 and 2009. We documented the scientific fields and the geographical origins of the studies, as well as the land uses, and compare these characteristics with a 25 years old review on earthworm management. The association of earthworm related keywords with ecosystem services related keywords was increasing with time, reflecting the growing interest in earthworm use in biodiversity and ecosystem services management. Conversely, no significant increase in the association between earthworms and disciplines such as ecological engineering or restoration ecology was observed. This demonstrated that general ecologically-based approaches have yet to emerge and that there is little exchange of knowledge, methods or concepts among balkanized application realms. Nevertheless, there is a strong need for crossing the frontiers between fields of application and for developing an umbrella discipline to provide a framework for the use of organisms to manage ecosystem services.     

Analysing the incorporation of sustainability themes into the university curricula: a case study of a Spanish public university

From an international view, several papers have analysed how sustainability themes are integrated into the university curricula. In Spain, few studies to date have examined the extent to which universities are incorporating sustainability themes into their curricula. In view of such considerations, this article examines the extent to which sustainability themes are being incorporated into the curricula of a Spanish public university strongly committed to signing sustainability policies and declarations. In addition, this study analyses the main barriers to the incorporation of sustainability themes into the curricula of this university. To accomplish this task, this article uses different methodological instruments over three phases through a case study approach. The findings of this study suggest how the university examined has many difficulties in incorporating, holistically or separately, sustainability themes in its formal courses despite having so many policies, regulations and a commitment to sustainability.     

Perception of drinking water in the Quebec City region (Canada): the influence of water quality and consumer location in the distribution system

The purpose of every water utility is to provide consumers with drinking water that is aesthetically acceptable and presents no risk to public health. Several studies have been carried out to analyze people's perception and attitude about the drinking water coming from their water distribution systems. The goal of the present study is to investigate the influence of water quality and the geographic location of consumers within a distribution system on consumer perception of tap water. The study is based on the data obtained from two surveys carried out in municipalities of the Quebec City area (Canada). Three perception variables were used to study consumer perception: general satisfaction, taste satisfaction and risk perception. Data analysis based on logistic regression indicates that water quality variations and geographic location in the distribution system have a significant impact on the consumer perception. This impact appears to be strongly associated with residual chlorine levels. The study also confirms the importance of socio-economic characteristics of consumers on their perception of drinking water quality.     

Debates on Sustainable Development: Towards a Holistic View of Reality

The paper analyzes the concept of sustainable development in the light of the different interpretations existing on the issue since its appearance and establishment as an ideal to lead humanity’s line of progress. Within these interpretations, a characteristic generation of diverse debates can be appreciated, arising from different perspectives, academic as well as ideological, aiming at describing, clarifying and determining their conceptual reach. Based on these facts a model of categorization for these debates has developed, a model in which interpretations generated on the concept of sustainable development were catalogued into four realms: conceptual, contextual, academic and geopolitical. The configuration of these four areas of debate, as well as the recognition of the diversity of interpretations existing on sustainable development, is a reflection of the intrinsic complexity of the phenomena, which affect the natural and social world, both at the local and global level. The analysis of this complexity is based on the subjectivity, which is inherent to the interpretation of these phenomena, with permanent reference to the cultural context from which the diverse discourses were structured. This global perspective on the state-of-the-art controversy concerning the idea of sustainable development as an articulatory axis reveals the necessity of building epistemological models, which can give a new direction to scientific research. From these new models, based on the analysis of the holistic character of reality, the subjective and the objective must be integrated in the generation of knowledge, which contributes usefully to the unceasing reconstruction of our world-(view). Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Heavy metals removal from electroplating wastewater by aminopropyl-Si MCM-41

The potential of removing nickel and copper from industrial electroplating wastewaters by using mesoporous materials with MCM-41 type structure functionalised with different ratios of aminopropyl groups, namely Na50, Na25 and Na5, were evaluated. The synthesised solids sorbents obtained were characterised by X-ray diffraction, elemental chemical analysis and IR spectroscopy. In preliminary experiments, studies were carried out to determine the optimal experimental conditions for the retention of heavy ions. Effects of concentration, optimal pH, interference with humic substances and other metals were studied for Na5, which showed the best capacity of absorption determined by the corresponding isotherm. This material has a greater selectivity against sodium, indicating that ionic strength does not affect the extraction. Results of an application of this material to remove nickel and copper in synthetic and real industrial wastewater samples from an electrochemical industry area are shown with successful results. The lowest level of nickel and copper were observed when Na5 was used. This observation suggests that reactive aminopropyl-Si MCM-41 and similar materials may be a promising and provide for alternative environmental technologies in the future.