Analysis of energy security and sustainability in future low carbon scenarios for Brazil

This study estimated a series of indicators to assess the energy security of supply and global and local environmental impacts under different mitigation scenarios through 2050 in Brazil, designed with the integrated optimization energy system model MESSAGE‐BRAZIL. The assessment of interactions between environmental impacts and energy security dimensions was complemented through the application of life cycle assessment (LCA) methodology. Overall results imply energy security establishes more synergies than trade‐offs in increasingly stringent mitigation scenarios, especially patent within the sustainability dimension, which increases energy security and provides additional benefits regarding climate change mitigation and air pollution emissions. It is still necessary to extend analysis to other energy sectors in addition to the power supply sector and to promote a better understanding of repercussions of energy scenario expansion in energy security.     

Cross‐level effects of demography and diversity climate on organizational attachment and firm effectiveness

We studied the impact of demographic diversity on individual attachment and firm unit performance in a relatively diverse organization. We implemented cross‐level regression to study gender and race/ethnic categorical, relational, and organizational demography in a sample of 26 units part of a regional restaurant chain. At the individual level, we found that diversity climate (DC) moderates the impact of relational and categorical demography on affective organizational commitment, organizational identification, and intention to quit. At the organizational level, we found that DC moderates the impact of organizational diversity on firm productivity and return on profit. We discuss the importance of organizational DC as organizational context on individual attachment, and implications for firm effectiveness in diverse organizations. Copyright © 2007 John Wiley & Sons, Ltd.     

Effects of climate change on species distribution, community structure, and conservation of birds in protected areas in Colombia

Climate change is expected to cause shifts in species distributions worldwide, threatening their viability due to range reductions and altering their representation in protected areas. Biodiversity hotspots might be particularly vulnerable to climate change because they hold large numbers of species with small ranges which could contract even further as species track their optimal habitat. In this study, we assessed the extent to which climate change could cause distribution shifts in threatened and range-restricted birds in Colombia, a megadiverse region that includes the Tropical Andes and Tumbes-Choco-Magdalena hotspots. To evaluate how climate change might influence species in this region, we developed species distribution models using MAXENT. Species are projected to lose on average between 33 and 43 % of their total range under future climate, and up to 18 species may lose their climatically suitable range completely. Species whose suitable climate is projected to disappear occur in mountainous regions, particularly isolated ranges such as the Sierra Nevada de Santa Marta. Depending on the representation target considered, between 46 and 96 % of the species evaluated may be adequately represented in protected areas. In the future, the fraction of species potentially adequately represented is projected to decline to 30–95 %. Additional protected areas may help to retain representativeness of protected areas, but monitoring of species projected to have the largest potential declines in range size will be necessary to assess the need of implementing active management strategies to counteract the effects of climate change.     

Distribution and temporal variation of trace metal enrichment in surface sediments of San Jorge Bay, Chile

Cu, Pb, and Hg concentrations were determined in surface sediment samples collected at three sites in San Jorge Bay, northern Chile. This study aims to evaluate differences in their spatial distribution and temporal variability. The highest metal concentrations were found at the site “Puerto”, where minerals (Cu and Pb) have been loaded for more than 60 years. On the other hand, Hg does not pose a contamination problem in this bay. Cu and Pb concentrations showed significant variations from 1 year to another. These variations seem to be a consequence of the combination of several factors, including changes in the loading and/or storage of minerals in San Jorge Bay, the dredging of bottom sediments (especially at Puerto), and seasonal changes in physical–chemical properties of the water column that modify the exchange of metals at the sediment–water interface. Differences in the contamination factor and geoaccumulation index suggest that pre-industrial concentrations measured in marine sediments of this geographical zone, were better than geological values (average shale, continental crust average) for evaluating the degree of contamination in this coastal system. Based on these last two indexes, San Jorge Bay has a serious problem of Cu and Pb pollution at the three sampling locations. However, only Cu exceeds the national maximum values used to evaluate ecological risk and the health of marine environments. It is suggested that Chilean environmental legislation for marine sediment quality—presently under technical discussion—is not an efficient tool for protecting the marine ecosystem.     

The uptake of hydrogen fluoride by a forest

A mathematical model of hydrogen fluoride (HF) deposition and accumulation of fluoride in a Eucalyptus rostrata forest has been developed. The model is based on tree physiology and meteorological principles. The data base for the model was derived from a literature survey of the physiological characteristics of E. rostrata and similar eucalyptus species and from current knowledge of meteorological processes in plant canopies.Comparison of the mathematical simulations with measurements in the vicinity of a source of HF (an aluminium reduction plant) shows that (1) the pattern of seasonal fluoride accumulation in leaves agrees with that seen in the field, and (2) the vertical pattern of accumulation inside tree leaves agrees with field observations. The simulations indicate that 50% of the released HF was deposited within 81 km of the source and that the concentration of HF in the air 81 km from the source was reduced to 2% of the concentration 1 km from the source. However, a very large forest area (20 600 km²) was required to achieve these reductions.     

Field Exposure Study of Polylactic Acid (PLA) Plastic Films in the Banana Fields of Costa Rica

For use by the banana industry of Costa Rica, polylactic acid (PLA) plastic ropes and banana finger shrouds must remain operational for 14 to 16 weeks, and they also must be able to break down in the soil after serving their purposes. The banana field at La Rebusca Farm (Costa Rica) and the experiment station at University of Costa Rica were selected for a field exposure study of Cargill EcoPla Generation II (GII) and Cargill EcoPla monolayer (Ca-I) PLA films. The average monthly temperature, relative humidity, and cumulative rainfall of the La Rebusca Farm and the University of Costa Rica site were 26 and 22°C, 92 and 84%, and 352 and 177 in., respectively. The PLA plastic films at the La Rebusca Farm lost their mechanical properties earlier than at the University of Costa Rica site because of the higher temperature and relative humidity of the banana farm. The Ca-I film meets the 14-week operational time frame and it is recommended for further studies as ropes and banana shrouds.     

Trace metal residues in tissues of two crustacean species from the Bahia Blanca Estuary,Argentina

Trace metals (total mercury, cadmium and zinc) were studied in several tissues of the edible shrimps Pleoticus muelleri and Artemesia longinaris from the Bahía Blanca estuary, Argentina. The digestive gland was shown to be the main organ in which metals accumulate, followed by the stomach-alimentary canal and abdominal muscle.The metal contents found in the present study largely exceeded those of the same species caught from the Argentine Sea. Mercury concentrations increased proportionally to the total length of the shrimps studied. Only little variation in metal concentrations among individuals seemed to exist.Finally, the usefulness of these species as bioindicators of trace metal pollution in the Bahía Blanca estuary is discussed.     

Distribution of Heavy Metals in Surface Sediments from an Antarctic Marine Ecosystem

The concentrations of lead, cadmium, copper,chromium, iron, manganese and zinc in surfacesediments collected from Potter Cove, in the 25de Mayo Island (King George Island), Antarctica, andits drainage basin, were measured by atomic absorptionspectroscopy. The obtained results were use todetermine the areal and vertical distribution of themetals of in the Cove and potential sources of thesemetals to this environment. The geochemical datasuggest that most of the metals found in Potter Coveconstitute a redistribution of autochthonous materialswithin the ecosystem. Therefore, the metalconcentrations can be considered to be present atnatural background levels in surface sediments.     

Mercury bioaccumulation in organisms from three Puerto Rican estuaries

We analyzed mercury levels in shrimp (Palaemonetes sp.), Blue Crabs (Callinectes sp.), fish (Tarpon Megalops atlantica and Tilapia Tilapia mossambica), lizards (Ameiva exsul), Cattle Egret (Bubulcus ibis) and Moorhen (Gallinula chloropus) in three estuaries in Puerto Rico in 1988. There were no quantifiable concentrations greater than the method detection limit of mercury in shrimp, crabs and lizards from any site. Mercury levels were also below detection limits in Tilapia, except for specimens collected at Frontera Creek, allegedly contaminated with mercury. However, mercury levels ranged from 92–238 g/kg (wet weight) in Tarpon, a predaceous fish that feeds on smaller fish. Few of the birds had detectable levels of mercury. Our results indicate relatively low concentrations of mercury in biota collected in all of the three estuaries at most trophic levels, although 10 of 12 Tarpon fillet samples from Frontera had detectable mercury compared to 3 of 12 fillet samples for the other two lagoons.This project was partially funded by an EPA consent decree (Dynamac, Inc.) and NIEHS grant (ESO 5022) to EOSHI.     

Physical and chemical characterisation of metal finishing industrial wastes

In EU countries approximately 150,000 tons/year of galvanic sludges are generated by 4000 industrial units from the corresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attempts to better understand the physical and chemical characteristics of these sludges, by studying 39 samples collected in different Portuguese industries that should represent all kinds of similar wastes independent of their place of generation. Chemical composition and leaching characteristics are given, together with density, grain size distribution, and specific surface area values. Statistical analysis was used for grouping the wastes according to chemical parameters, which might be useful to predict potential reuse as raw materials for different applications.