Relevance study of bare and coated zero valent iron nanoparticles for lindane degradation from its by-product monitorization

Zero-valent iron nanoparticles (NZVI) as well as polymer–stabilized nanoparticles were synthesized and used for lindane (γ-hexachlorocyclohexane) degradation in aqueous solution. To study the effectiveness of the different coated nanoparticles, simple and rapid analytical methods have been developed to measure and to detect lindane and its by-products. For the monitorization of lindane degradation solid-phase extraction (SPE) was used, while volatile by-products formation measurement was carried out by headspace-solid phase microextraction (HS–SPME) followed by GC/MS. The SPE–GC/MS method provides low detection limits (0.2 μg L⁻¹), high recovery (above 95%) and it is a valuable tool for kinetic studies of the degradation process for each polymer used, while HS–SPME–GC/MS has proved to be an effective tool for the extraction and evaluation of volatile degradation by-products.     

Agro-industry sugarcane residues disposal: the trends of their conversion into energy carriers in Cuba

The goal of the present work was to carry out a review of the disposal practices for the agro-industry's sugarcane residue and the trends of energy use in Cuba. The lack of an alternative energy carrier to electricity with storage capability for use in off-season has to date been an unsolvable question. The improvement of cogeneration capacity via implementation of CEST or BIG/GTCC and the barriers for their implementation, the introduction of a medium size (3 ton/h) fast pyrolysis module (FPM3) as a solution for off-season energy demand in the agro-industry, and an assessment of the energy required to do so, were also analyzed. Bio-oil production from bagasse and sugarcane agriculture residues (SCAR) and their particularities at the sugar mill are treated. The influence of sugar facility production process configuration is analyzed. The fast pyrolysis products and the trends of their end uses in Cuba are presented. The production cost of a ton of Bio-oil for FPM3 conditions was calculated at 155 USD/ton and the payback time as a function of selling price between 160 and 110 USD/ton was estimated to be from 1.5 to 4 years. The economic feasibility of the FPM3 was estimated, comparing the added values for three scenarios: 1st case, currently-used sugar production, 16.5 USD/ton of cane; 2nd case, factoring in the cogeneration improvement, 27 USD/ton of cane; and 3rd case, with cogeneration improvement and Bio-oil production, 40 USD/ton of cane. The energy use of SCAR and the introduction of FPM3 in the sugar mill are promising improvements that could result in a potential surplus of 80 kWh(e)/ton of cane in-season, or 6 x 10(6)ton of Bio-oil (LHV=15 MJ/kg) for use off-season in a milling season of 4 million tons of raw sugar.     

New Probit equations for the calculation of thermal effects on humans

In this paper new Probit equations are proposed to estimate damage produced by thermal radiation on humans (for first- and second-degree burns). They are compared to empirical threshold values and also to existing Probit equations. Results obtained are in good agreement with previous empirical experience. They also provide better estimations than existing equations. When an analysis is performed to study the evolution in the percentage of affected people by different degrees of damages, results show that proposed equations produce more consistent results than existing equations.     

Single and joint effects of regional- and local-scale variables on tropical seagrass fish assemblages

Seagrass beds are highly important for tropical ecosystems by supporting abundant and diverse fish assemblages that form the basis for artisanal fisheries. Although a number of local- and regional-scale variables are known to influence the abundance, diversity and assemblage structure of seagrass-associated fish assemblages, few studies have evaluated the relative and joint (interacting) influences of variables, especially those acting at different scales. Here, we examined the relative importance of local- and regional-scale factors structuring seagrass-associated fish assemblages, using a field survey in six seagrass (Thalassodendron ciliatum) areas around Unguja Island (Zanzibar, Tanzania). Fish density and assemblage structure were mostly affected by two regional-scale variables; distance to coral reefs, which positively affected fish density, and level of human development, which negatively affected fish density. On the local scale, seagrass biomass had a positive (but weaker) influence on fish density. However, the positive effect of seagrass biomass decreased with increasing level of human development. In summary, our results highlight the importance of assessing how multiple local and regional variables, alone and together, influence fish communities, in order to improve management of seagrass ecosystems and their services.     

Detection of polybrominated diphenyl ethers in tilapia (Oreochromis mossambicus) from O'ahu, Hawai;i

Polybrominated diphenyl ethers (PBDEs) have been detected for the first time at a range from 231.58 to 685.61 ng g(-1) lipid weight in the muscles of tilapia (Oreochromis mossambicus) collected from O'ahu, an island of the geographically isolated Hawaiian archipelago.     

Environmental economic,political and ethical integration in a common decision-making framework

This article develops a decision-making framework for environmental management that integrates technical, economic, political and legal, and ethical decision levels. It attempts to show how these decision levels can be ordained, integrated and interconnected and postulates a hierarchic concentric sphere system that proposes an environmental management model for long-term solutions. This model can be used as a check list for environmental management decision-making and also as a guide for environmental conflict resolution where environmental problems necessitate several levels of decision making. It integrates various environmental ethical positions and evaluates political decisions into a comprehensive, broadly applicable multidisciplinary approach. The objective of this decision-making model is to interconnect into a simplified sequence different levels of environmental management processes in order to account for sustainability, efficacy, efficiency and the acceptability of environmental management processes in the long term. This is done by observing when an environmental problem needs to be solved within a certain sphere of solutions and when it requires wider frameworks, how these can be established and how this process proves that solidarity is the widest and most reasonable sphere.     

Detection and quantitative analysis of polychlorinated biphenyls in tilapia from Hawaiian waters

The purpose of this study was to investigate polychlorinated biphenyls (PCBs) contamination in tilapia (Oreochromis mossambicus) collected from the Manoa stream and Ala Wai Canal of O'ahu, an island of the geographically isolated Hawaiian archipelago. Our results show that the average concentrations of PCBs varied from 51.90 to 89.42 ng g(-1) lipid weight for the sampling sites. Relative toxic potencies (RTPs) and toxic equivalencies (TEQs) were determined to be 20.38-40.60 ng TCDDg(-1) lipid weight and 2.89-4.17 ng TEQ g(-1) lipid weight by 7-ethoxy-resorufin-O-deethylase (EROD) activity analysis and calculation of PCB concentrations based on toxic equivalency factors (TEFs), respectively. Penta-chlorinated congeners were found to be predominant, which revealed that Aroclor 1254 was a possible major source of PCBs in our fish samples. PCB 118, an indicator PCBs, constituted more than 55% and 30% of the total PCBs and TEQs, respectively. In addition, PCB 118 was found to have a linear correlation to the total PCBs (R=0.975) and TEQs (R=0.782). Detection of concentrated PCBs in Hawaiian waters suggests a potentially adverse impact of this pollutant on human health, as well as ecological systems, and suggests the necessity of environmental monitoring and hazard assessment of PCBs within the Hawaiian Islands.     

Bioaccumulation of persistent organic pollutants in female common dolphins (Delphinus delphis) and harbour porpoises (Phocoena phocoena) from western European seas: geographical trends, causal factors and effects on reproduction and mortality

Concentrations of polychlorinated biphenyls (PCBs) in blubber of female common dolphins and harbour porpoises from the Atlantic coast of Europe were frequently above the threshold at which effects on reproduction could be expected, in 40% and 47% of cases respectively. This rose to 74% for porpoises from the southern North Sea. PCB concentrations were also high in southern North Sea fish. The average pregnancy rate recorded in porpoises (42%) in the study area was lower than in the western Atlantic but that in common dolphins (25%) was similar to that of the western Atlantic population. Porpoises that died from disease or parasitic infection had higher concentrations of persistent organic pollutants (POPs) than animals dying from other causes. Few of the common dolphins sampled had died from disease or parasitic infection. POP profiles in common dolphin blubber were related to individual feeding history while those in porpoises were more strongly related to condition.     

Empirical selection between least-cost and current-flow designs for establishing wildlife corridors in Gabon

Corridors are intended to increase species survival by abating landscape fragmentation resulting from the conversion of natural habitats into human-dominated matrices. Conservation scientists often rely on 1 type of corridor model, typically the least-cost model or current-flow model, to construct a linkage design, and their choice is not usually based on theory or empirical evidence. We developed a method to empirically confirm whether corridors produced by these 2 models are used by target species under current landscape conditions. We applied this method in the Gamba landscape between 2 national parks in southwestern Gabon. We collected signs of presence of African forest elephant (Loxodonta cyclotis), forest buffalo (Syncerus caffer nanus), and 2 apes, western lowland gorilla (Gorilla gorilla gorilla) and central chimpanzee (Pan troglodytes troglodytes), on transects. We used patch-occupancy models to identify least-cost and current-flow corridors for these 4 species. On average, 28.7% of current-flow corridors overlapped with least-cost corridors, confirming that the choice of corridor model can affect the location of the resulting linkage design. We validated these corridors by monitoring signs and examining camera detections on new transects within and outside modeled corridors. Current-flow corridors performed better than least-cost corridors for elephants, whereas the opposite was found for buffalo and apes. Locations of the highest priority corridors for the 3 taxa did not overlap, and only 18.3% of their combined surface was common among 2 species. We used centrality metrics to calculate the average contribution of corridor pixels to landscape connectivity and derived an index that can be used to prioritize corridors. As a result, we recommend protecting at least 17.4% of the land surface area around Gamba town to preserve the preferred travel routes of the target species.     

Heavy metal content and speciation in groundwater of the Guadiamar river basin

This work presents the conclusions of a speciation study concerning Zn, Cd, Pb and Cu in groundwater from ten wells in the alluvial aquifers of the Guadiamar river, affected by Aznalcollar mine tailing spill (April 1998). The sampling campaign took place in January 2000, almost two years after the mining accident. Four metal fractions were determined: labile metal forms, H+ exchangeable metal forms, strongly inert forms (associated with organic and inorganic matter in solution), and forms associated with suspended matter. Total metal concentration in groundwater followed the trend Cd < Pb < Cu < Zn. The speciation study showed that Zn and Cd were present to a great extent in available forms (labile and H+ exchangeable), while Pb and Cu were found mostly in the less available forms (strongly inert). These results can illustrate the potential value of the speciation tool for the follow-up of spill-induced pollution in the area.