Cork stoppers as an effective sorbent for water treatment: the removal of mercury at environmentally relevant concentrations and conditions

The technical feasibility of using stopper-derived cork as an effective biosorbent towards bivalent mercury at environmentally relevant concentrations and conditions was evaluated in this study. Only 25 mg/L of cork powder was able to achieve 94 % of mercury removal for an initial mercury concentration of 500 μg/L. It was found that under the conditions tested, the efficiency of mercury removal expressed as equilibrium removal percentage does not depend on the amount of cork or its particle size, but is very sensitive to initial metal concentration, with higher removal efficiencies at higher initial concentrations. Ion exchange was identified as one of the mechanisms involved in the sorption of Hg onto cork in the absence of ionic competition. Under ionic competition, stopper-derived cork showed to be extremely effective and selective for mercury in binary mixtures, while in complex matrices like seawater, moderate inhibition of the sorption process was observed, attributed to a change in mercury speciation. The loadings achieved are similar to the majority of literature values found for other biosorbents and for other metals, suggesting that cork stoppers can be recycled as an effective biosorbent for water treatment. However, the most interesting result is that equilibrium data show a very rare behaviour, with the isotherm presenting an almost square convex shape to the concentration axis, with an infinite slope for an Hg concentration in solution around 25 μg/L.     

Combining remote sensing and household level data for regional scale analysis of land cover change in the Brazilian Amazon

Land cover change in the Brazilian Amazon depends on the spatial variability of political, socioeconomic and biophysical factors, as well as on the land use history and its actors. A regional scale analysis was made in Rondônia State to identify possible differences in land cover change connected to spatial policies of land occupation, size and year of establishment of properties, accessibility measures and soil fertility. The analysis was made based on remote sensing data and household level data gathered with a questionnaire. Both types of analyses indicate that the highest level of total deforestation is found inside agrarian projects, especially in those established more than 20 years ago. Even though deforestation rates are similar inside and outside official settlements, inside agrarian projects forest depletion can exceed 50% at the property level within 10–14 years after establishment. The data indicate that both small-scale and medium to large-scale farmers contribute to deforestation processes in Rondônia State encouraged by spatial policies of land occupation, which provide better accessibility to forest fringes where soil fertility and forest resources are important determinants of location choice.     

Occurrence and ecological risk assessment of pharmaceuticals and cocaine in the urban drainage channels of Santos beaches (São Paulo,Brazil): a neglected,but sensitive issue

Environmental Science and Pollution Research - In some Brazilian coastal cities, it is common to observe ‘black tongues’ in beaches, i.e. a mixture of urban runoff and untreated...     

Who participates in conservation initiatives? Case studies in six rural communities of Mexico

Previous studies attempting to explain the factors that determine local participation in conservation initiatives have concluded that socio-political exclusion is the main barrier to being involved in such initiatives. Such studies have not differentiated between different types of conservation initiatives. In this paper, we contribute to the literature analyzing the socio-cultural correlates of participation, by differentiating between participation in three types of conservation schemes: protected areas, payment for environmental services, and community conservation. We use data obtained from six rural communities in Mexico, where different combinations of conservation schemes are found. Through linear regression analysis, we explore the relationship between participation and (1) the community of residence; (2) demographics; and (3) socioeconomic characteristics of individuals. Our results suggest that local participation in conservation strategies depends, to a large extent, on the socio-political context in which they are embedded and that the exclusion of women and young adults is clearly consistent.     

Genetic structure in lagoons: the effects of habitat discontinuity and low dispersal ability on populations of <Emphasis Type="Italic">Atherina boyeri</Emphasis>

Atherina boyeri is a common inhabitant of the Mediterranean brackish and coastal waters. Several recent studies proposed the recognition of three distinct forms/species (one lagoon/freshwater and two marine) within an A. boyeri complex. In this study, we used 10 newly available microsatellite loci to better define the genetic structure of the lagoon form. A total of 428 fishes from 11 lagoons along the Italian and Albanian coasts and three Italian lakes were analyzed. A pronounced genetic spatial structure was confirmed for all considered geographic scales (near, medium and broad). A restricted gene flow was detected, suggesting reduced population connectivity. The comparison of present data and previous studies, based on mtDNA and RAPD markers, allowed a preliminary identification of the roles of recent factors (gene flow, habitat discontinuity and water currents) and past events (e.g., Pleistocene glaciations) in shaping the pattern of genetic differentiation.     

An individual-based analysis of the dynamics of two coexisting phytoplankton species in the mixed layer

In marine ecosystems ecological and environmental conditions continuously change, possibly supporting the wide range of phytoplankton species coexisting in aquatic environments. Phytoplankton communities are not homogeneously distributed in the water column due to the spatial and temporal variability of turbulent mixing and the concurrent biological response. In this paper an individual-based model (Lagrangian method) simulating the basic physiology of two coexisting phytoplankton species has been developed. The species, sharing the same availability of light and nutrient resource, are characterized by different photo-physiological parameters. The spatial and temporal evolution of turbulent mixing is simulated introducing vertical profiles of measured eddy diffusivity. Three case studies have been examined to analyze the role of environment–individual interactions in determining bloom conditions for both the selected species. The organisms experience recurrent fluctuations of light, temperature, and nutrient concentration gradients, due to the turbulent mixing in the water column, which have significant effects on the growth of the phytoplankton species. In all the numerical experiments, the temporal and spatial variability of different forcings do not support the prevalence of one species over the other over the time scale typical of a phytoplankton bloom.A well mixed water column favours the growth of both the populations while a variable mixing regime limits their growth reducing the photophysiological differences between the species.     

“Return” and Extension Actions After Ethnobotanical Research: The Perceptions and Expectations of a Rural Community in Semi-arid Northeastern Brazil

The scientific community has debated the importance of “return” activities after ethnobiological studies. This issue has provoked debate because it touches on the ethics of research and the relationships with the people involved in these studies. This case study aimed to investigate community perception of an ethnobotany research project that was carried out in the semi-arid region of northeastern Brazil. Furthermore, we reported how the residents of this rural community felt about participating in the activities of “return” that arose from the projects. Our findings demonstrate that “return” activities should be planned from the design phase of the research until its closure as a lifelong process that allows the communities involved to gradually take ownership of the information and actions that are being generated. Similarly, we argue that such activities must be negotiated with the people of the community so that they have decision-making power and autonomy to decide what is most relevant to their lives.     

The problem of disposing of plaster waste from building sites: problem structuring based on value focus thinking methodology

Plaster is a material which is widely used in Brazil on construction sites. However, its use in recent years has been limited by a legal resolution on the environment introduced in Brazil. One of the regions most affected by these restrictions is the Northeast where the strategic importance of plaster for the region is apparent from the extensive economic development, centered on the gypsum pole of Araripe in the state of Pernambuco. This problem has involved many interested parties, among whom are plaster producers, plastering companies, builders, unions (for plaster workers, and construction workers), Town Halls, and so forth. Therefore, there is a need to structure the problem with a view to obtaining a better understanding of the problem given the lack of information on the real decision problem. To reach this objective, value focus thinking (VFT), a methodology that addresses how values can be used to improve the decision making process, was applied and the problem was structured. Thus, it was possible for the parties involved to clarify their objectives, and specify more precisely the consequences and constraints for the decision problem. In addition, each party involved could get a better understanding of their own wishes. In conclusion, the VFT methodology application enables the parties involved to make more consistent decisions, and therefore to ensure that plaster will continue to be used in the construction industry.