Immobilization of iodide on copper(I) sulfide minerals

In the goal of finding efficient scavengers for radioiodide in conditions (pH, pE) close to those encountered in deep geological sites, sorption of iodide ions on cuprous sulfide minerals (especially roxbyite, Cu(1.75)S) has been studied. Surface analysis by X-ray photoelectron spectroscopy has shown that commercial cuprous sulfides are covered by an oxidized overlayer (mainly in the form of CuSO(4)). Therefore, a synthetic procedure to get roxbyite (typically by mixing Na(2)S with an aqueous suspension of commercial Cu(2)O) was applied to produce pure samples with clean surfaces. Batch equilibration of cuprous sulfide particles suspended in aqueous solutions containing iodide species has revealed significant consumption of iodide. The sorption mechanism involves the formation of a surface complex via the exchange of surface hydroxyl groups by iodide anions, as highlighted by a transient pH increase during the immobilization process. Other copper and mixed copper-iron sulfides (e.g. CuS, CuFeS(2)), which are stable over wide pH and potential ranges are also likely to accumulate iodide species. Because of the specific interaction between iodide and copper(I) centers on the minerals, high distribution coefficients (>1000 ml/g) were observed.     

Effects of atrazine and nicosulfuron on freshwater microalgae

Growth modifications caused by various concentrations of atrazine and nicosulfuron were monitored in closed and continuous culture of Chlorella vulgaris (chlorophyta), Navicula accommoda (diatomophyta), and Oscillatoria limnetica (cyanophyta). The concentration at which algal growth rate was reduced twofold (EC50) was determined in the three species for both herbicides. Comparatively, the two toxicants were applied at 10 microg/l level in microcosms inoculated with natural phytoplankton from Lake Geneva. The relative abundances of major phytoplanktonic species were measured by algal cell count at the beginning and at the end of each experiment. Atrazine and nicosulfuron have different targets in plant metabolism, respectively, photosystem II (PSII) and acetolactate synthase (ALS), and the expected effects were different. Generally, the cultured phytoplankton exhibited various sensitivities, depending on species or herbicide. In the microcosms, the major taxa of natural phytoplanktonic samples exhibited various patterns, from acute toxicity to growth enhancement. For example, the diatoms inside the community were not affected by atrazine and nicosulfuron, except for Stephanodiscus minutulus that was sensitive to both, and Asterionella/formosa that was sensitive only to nicosulfuron. The specific physiology and the relationships among the phytoplanktonic communities have to be carefully considered when one would try to predict the extent of herbicide action on natural phytoplankton using in vitro tests. There is a need to test the toxic effect on various cultured strains, representative of most of the taxonomic composition of natural communities, to take into account the wide range of sensitivities and reaction to herbicide contamination. But this is not enough to give a solid frame when transposing the results to the field, and the use of more ecologically relevant systems is recommended.     

Assessment of environmental changes in the Orinoco River delta

Major anthropogenic driven changes in the hydrologic and sedimentation patterns of the Orinoco River have had an impact on environmental conditions in the delta. The abrupt water flow reduction from 3,600 to 200 m³ s^–1 in one of its major distributaries resulting from dam construction forced its transformation from a fresh-water body into a tidal channel with an increase in salinity level (as far as 100 km upstream) and with well-mixed water at the mouth and estuarine connection to the Paria Gulf. Three different sectors along this distributary can be identified (indicated by the Na/Cl ratio in the water). As a result, noticeable changes have occurred in the mangrove community which moved about 60 km further upstream. The changes have also promoted the formation of new islands of sediment progradation at the mouth of this distributary, where successional colonization and species replacement by different species of grasses and mangroves take place. Electronic Publication     

Do protected areas really work to conserve species? A case study of three vulnerable woody species in the Sudanian zone of Burkina Faso

Natural vegetation and native plant species contribute significantly to the daily needs of local people especially in developing countries. This exerts a high pressure on local species and jeopardizes the conservation of the most vulnerable plants. In Burkina Faso, conservation measures, such as the creation of protected forests, have been taken to safeguard the remaining indigenous vegetation. However, little is known about the effectiveness of these protected areas in conserving biodiversity. This study assessed and compared the population structures and regeneration potential of three vulnerable woody species—Diospyros mespiliformis Hochst., Prosopis africana (Guill. & Perr.) Taub. and Sterculia setigera Del.—in protected and unprotected areas in the Sudanian zone of Burkina Faso. The population structure and regeneration pattern of each species were compared between the North and South Sudanian sectors of Burkina Faso. The populations of all three species were unstable in both protected and unprotected areas. D. mespiliformis and P. africana displayed relatively good regeneration while P. africana lacked regeneration in unprotected areas. Regeneration was poor for S. setigera, regardless of protection status. The results suggest that the populations of the targeted species are unstable, regardless of the protection status of the area considered. This is probably due to the high anthropogenic pressure facing natural resources and raises serious concerns about the effectiveness of the protected areas in conserving biodiversity. Urgent measures are needed to ensure effective and efficient management and conservation of biodiversity in the protected areas of Burkina Faso.     

Knowledge for sustainable development: a worldviews perspective

A huge tension exists between recognizing sustainable development (SD) as a meta-discourse and accepting a limitless interpretational width. We analyse the impacts of diversity of worldviews on the interpretation of SD—as a knowledge-based concept—through a critical literature review, resulting in recommendations on the topic. We apply a social-constructionist approach, appreciating the complex socio-ecological interactions at the heart of SD. Only recently worldviews are recognized as constitutive elements of SD. Little attention has been given to the impacts on generated knowledge for SD. Variety of worldviews induces a variety of knowledge claims and needs. To retain SD’s ‘universal’ appeal as practical decision-guiding strategy for policy and action, we propose an integrative approach towards knowledge for SD—entailing an explicit pluralization of knowledge. SD should be re-interpreted as a joint worldviews construct, embracing a diversity of views in collaborative research and co-production of knowledge. Interpreting SD as a joint endeavour is necessary to overcome historical obstacles like cultural hegemony and a hierarchy of knowledge systems. We identified the following requirements for an inclusive knowledge for SD paradigm: re-interpretation of SD as a worldview constructs in progress; interpretative flexibility; co-production of knowledge; subjectivity awareness and self-reflexivity; respect for a diversity of worldviews/knowledges; identifying shared goals; collaborative research; a systems approach; transdisciplinarity; and recognition of contextuality. Further research—concerning potential methodologies and typologies—to reconcile variety of worldviews and knowledge systems in a joint SD worldviews construct is urgently needed.     

Assessment of the natural-cultural resources in Çanakkale for nature-based tourism

While the world is going into different tourism expectations, the tourism understanding in Turkey is defined as tourism in the sea-sand-sun triangle. However, it is possible to contribute to the income and local development of the indigenous people by developing nature-based tourism. Besides, with the sustainable use and preservation of the natural-cultural assets, the damage of the traditional tourism industry on the natural and cultural environment could be reduced. In this study, it is aimed to bring up the nature-based tourism concept in Çanakkale by evaluating the nature-based tourism industry in the general of Turkey and assessing the natural-cultural resources that Çanakkale comprehends. The most important areas that have a nature-based tourism potential in Çanakkale and the tourism activities that are most suitable for these areas have been determined.     

Using fuzzy set theory to address the uncertainty of susceptibility to drought

This paper presents the technical aspects of a new methodology for assessing the susceptibility of society to drought. The methodology consists of a combination of inference modelling and fuzzy logic applications. Four steps are followed: (1) model input variables are selected—these variables reflect the main factors influencing susceptibility in a social group, population or region, (2) fuzzification—the uncertainties of the input variables are made explicit by representing them as ‘fuzzy membership functions’, (3) inference modelling—the input variables are used to construct a model made up of linguistic rules, and (4) defuzzification—results from the model in linguistic form are translated into numerical form, also through the use of fuzzy membership functions. The disadvantages and advantages of this methodology became apparent when it was applied to the assessment of susceptibility from three disciplinary perspectives: Disadvantages include the difficulty in validating results and the subjectivity involved with specifying fuzzy membership functions and the rules of the inference model. Advantages of the methodology are its transparency, because all model assumptions have to be made explicit in the form of inference rules; its flexibility, in that informal and expert knowledge can be incorporated through ‘fuzzy membership functions’ and through the rules in the inference model; and its versatility, since numerical data can be converted to linguistic statements and vice versa through the procedures of ‘fuzzification’ and ‘defuzzification’.     

Radon concentration measurements in mofettes from Harghita and Covasna counties, Romania

In the Harghita volcanic range (Romania) there are many occurrences of dry CO(2) emanations, called mofettes. The emanating gas with high carbon dioxide content has a proved curative effect. The gas also contains important quantities of radon. Since the mofettes are used in curative purposes in several illnesses, in most of the cases without medical supervising, has been proposed to determine the radon activity concentration in some of the most frequented mofettes from Romania. The seasonal variations have also been monitored and were calculated the effective doses received by the patients during a cure. The radon activity concentrations' levels above the mofettes indoor air range between 548 and 10 717Bq/m(3) while within the gas pools' values between 3210 and 32 781Bq/m(3) have been measured. The effective dose received by the patients during a cure is between 0.0086 and 0.16mSv. No major seasonal variations of the radon activity concentrations levels have been pointed out so far in the studied mofettes.