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Contamination of port zone sediments by metals from Large Marine Ecosystems of Brazil Texto completo
2012
Buruaem, Lucas M. | Hortellani, Marcos A. | Sarkis, Jorge E. | Costa-Lotufo, Leticia V. | Abessa, Denis M.S.
Sediment contamination by metals poses risks to coastal ecosystems and is considered to be problematic to dredging operations. In Brazil, there are differences in sedimentology along the Large Marine Ecosystems in relation to the metal distributions. We aimed to assess the extent of Al, Fe, Hg, Cd, Cr, Cu, Ni, Pb and Zn contamination in sediments from port zones in northeast (Mucuripe and Pecém) and southeast (Santos) Brazil through geochemical analyses and sediment quality ratings. The metal concentrations found in these port zones were higher than those observed in the continental shelf or the background values in both regions. In the northeast, metals were associated with carbonate, while in Santos, they were associated with mud. Geochemical analyses showed enrichments in Hg, Cd, Cu, Ni and Zn, and a simple application of international sediment quality guidelines failed to predict their impacts, whereas the use of site-specific values that were derived by geochemical and ecotoxicological approaches seemed to be more appropriate in the management of the dredged sediments.
Mostrar más [+] Menos [-]Monitoring and visualizing of PAHs into mangrove plant by two-photon laser confocal scanning microscopy Texto completo
2012
Wang, Ping | Wu, Tun-Hua | Zhang, Yong
In this paper, we described the applications of two-photon laser confocal scanning microscopy (TPLCSM) for in situ monitoring and visualizing the localizations and movements of naphthalene, phenanthrene, and pyrene into living Aegiceras corniculata (L.) Blanco seedlings (A. corniculata). Experimental results demonstrated that all of the polycyclic aromatic hydrocarbons (PAHs) were observed entering into the root of A. corniculata and being transmitted to the stem. The transport processes and subsequent storages of the three typical PAHs into A. corniculata were similar. Further studies indicated that the transmission rates of the PAHs in A. corniculata were in the order of naphthalene>phenanthrene>pyrene. Compared with the control group, the growth of the A. corniculata was inhibited by these three specific PAHs, and the inbibitional effect of naphthalene was the most obvious (P<0.05). Furthermore, without the need for sample manipulation or modification this TPLCSM provides us a real-time tool for direct observation of organic chemicals within plants.
Mostrar más [+] Menos [-]Benthic infauna variability in relation to environmental factors and organic pollutants in tropical coastal lagoons from the northern Yucatan Peninsula Texto completo
2012
Kuk-Dzul, J Gabriel | Gold-Bouchot, G. | Ardisson, P.-L.
We examine the abundance and species composition variability of benthic infauna from tropical coastal lagoons in relation to environmental factors and organic pollutants. Sediment samples were collected at 40 sites in four lagoons in the northern Yucatan Peninsula. A total of 7985 individuals belonging to 173 species were sampled. While the eastern lagoons were dominated by polychaetes, the western ones were dominated by crustaceans. Overall, polychaetes had the highest abundance (48%), followed by crustaceans (42%). According to canonical correspondence analysis, species attributes were correlated with water salinity, pH and temperature, but also with sediment pentachlorobenzene, trichlorobenzene, and low molecular weight polycyclic aromatic hydrocarbons. Some pollutants exceeded sediment quality guidelines, representing a potential environmental risk to benthic infauna. Together, environmental factors and pollutants explained 52% of the variance in abundance and species composition among sites.
Mostrar más [+] Menos [-]Detecting shifts in ecosystem functioning: The decoupling of fundamental relationships with increased pollutant stress on sandflats Texto completo
2012
Lohrer, A. M. (Andrew M.) | Townsend, Michael | Rodil, Iván F. | Hewitt, Judi E. | Thrush, Simon F.
In this study, we investigated the influence of low level contamination by copper, lead and zinc on the functioning of estuarine sandflat ecosystems by comparing the strength and variability of relationships between benthic macrofauna and fluxes (oxygen and nutrients) at three clean and three mildly contaminated sites. Specifically, as indicators of ecosystem functioning, we examined relationships between bivalve biomass, total benthic respiration and ammonium release, and ammonium uptake and benthic primary production. Furthermore, a small amount of organic matter was added to experimental plots at all sites (35g/0.2m²) to evaluate stress-on-stress responses relative to controls. Relationships were strongest at the clean sites (steepest slopes, highest r² values, lowest p-values) and weakest at the mildly contaminated sites and in organically enriched plots. Our results suggest that changes in ecosystem functioning may be occurring at mild (<ERL) levels of pollution that are unlikely to cause widespread mortality of macrofauna.
Mostrar más [+] Menos [-]X-ray difraction analysis of desulfurant sorbents prepared by mixing calcined sewage sludge and CaO in distilled or seawater Texto completo
2012
Renedo Omaechevarría, Josefina | González Pellón, Lorenzo | Fernández Ferreras, Josefa | Universidad de Cantabria
Desulfurant sorbents prepared by hydration, in sea or distilled water, of calcined sewage sludge (ash) and CaO at CaO/ash weight ratios of 0.2 or 3 at room temperature or at 90 º C, were characterized by X-ray diffraction in order to relate the X-ray composition of the sorbents to the preparation process and to the specific surface area of the obtained sorbents. Results show that the main compounds detected in the sludge´s ash are the same than those found in bibliography for the calcined sludge. In all the sorbents, independently of the preparation conditions, Ca(OH)2 was found instead of CaO used as raw material. New and different crystalline products were found in the sorbents depending on the preparation conditions. All the sorbents prepared in seawater contain NaCl in their composition; the specific surface area of the sorbents increased with hydration time and temperature and was lower when seawater was used for hydration. | We are thankful to MICINN in Spain, National Plan for scientific Research, Development and innovation, for financial support under Project: MAT2010-18862.
Mostrar más [+] Menos [-]Best available techniques in municipal solid waste incineration: state of the art in Spain and Portugal Texto completo
2012
Margallo Blanco, María | Aldaco García, Rubén | Bala Gala, Alba | Fullana i Palmer, Pere | Irabien Gulías, Ángel | Universidad de Cantabria
In the year 2010 more than 24 Mt and 5 Mt of Municipal Solid Waste (MSW) were generated in Spain and Portugal. Landfilling, incineration and recycling are the most common treatments. In 2010, in the Iberian Peninsula between 58-6 2 % of the MSW generated was sent to the landfill, 9-19 % was incinerated and the rest was recycled and composting (EUROSTAT, 2010). Despite landfilling is still the most common practice, waste treatment by means of an incineration process has increased. The main advantages of this type of waste treatment are the reduction of mass and volume of residues and the energy recovery. Nevertheless, incineration had gained a bad reputation owing to the environmental impact, in particular, due to the emissions of acid gases, dioxins and furans (PCDD/F) and greenhouse gases. To assess the environmental advantages and disadvantages as well as the potential environmental impacts of waste incineration a life cycle perspective is required. Within this framework is the development of FENIX-Giving Packaging a New Life, a 3-year European LIFE+ funded project. This work is just the first step within this project where a database and a model based on Life Cycle Assessment (LCA) to assess the environmental impacts of waste incineration in Spain and Portugal will be developed. Particularly, the aim of this paper is to review the different technologies applied to MSW solid waste incineration and to carry out both the diagnosis of the current situation at the incineration plants in Spain and Portugal and to collect data to develop the Life Cycle Inventory (LCI).
Mostrar más [+] Menos [-]Study of the thermal behavior of sewage sludge from a WWTP in Cantabria (Spain) by TG-DSC-MS Texto completo
2012
Fernández Ferreras, Josefa | González Martínez, Fernando | Pesquera González, Carmen | Blanco Delgado, Carmen | Renedo Omaechevarría, Josefina | Universidad de Cantabria
According to European Directive and national regulations in Spain, techniques based on thermal decomposition are proposed for the sewage sludge disposal. In this work, the sludge from the wastewater treatment plant (WWTP) of Casar de Periedo, in Cantabria (Spain) is studied by Thermogravimetry – Differential Scanning Calorimetry – Mass Spectrometry (TG –DSC – MS). A sample of this sludge was submitted, after drying, to different atmospheres: 100 % He, N2 /air or He/air 80/20 and 100 % air, from 20 to 900 ºC, to study primary decomposition reactions in pyrolysis, gasification and combustion respectively. The purpose was to determine the weight loss at different temperatures, the heat flow at each atmosphere and the presence of some gas products like H2, CO, CO2, CH4, or HCl, SO2, SO3, NO and NO2 released, these last five gases to know the contaminants emitted. Combustion conditions (air) rend the greatest mass loss and energy production. Reactions take place at lower temperatures, being mainly CO2 and H2O the products detected in MS, with little amounts of CH4, as it is expected for mainly total oxidation reactions. In gasification conditions, essayed with two atmospheres (N2-air and He-air), quantitative results found are similar, but the highest thermal conductivity of He produces exothermic reactions at lower temperatures, observed in the mass loss and heat flow profiles. From reactions of decomposition, partial oxidation and total oxidation, CO2, H2, H2O and CH4, were identified by MS. Pyrolysis conditions (He) produce the lowest mass loss and slightly endothermic reactions, mainly because of decomposition reactions. Higher H2 amounts were obtained at higher temperatures than in gasification conditions. No gas contaminant (HCl, SO2, SO3, NO and NO2) has been detected by MS, considering this sewage sludge as a “clean sludge”. Comparing the thermal behaviour of the sewage sludge of this plant to that obtained in the WWTP of Santander, the sludge from Casar de Periedo is more appropriated to thermal valorization. | We are thankful to MICINN in Spain, National Plan for scientific Research, Development and innovation, for financial support under Project: MAT2010-18862.
Mostrar más [+] Menos [-]Minimization of energy consumption for chemicals ultrapurification processes Texto completo
2012
Abejón Elías, Ricardo | Garea Vázquez, Aurora | Irabien Gulías, Ángel | Universidad de Cantabria
Semiconductor industry requires ultrapure chemicals to manufacture microelectronic devices. Hydrogen peroxide is one of the most demanded chemical by the semiconductor industry and ultrapurification processes are needed to achieve the electronic grade requirements for this chemical. Among all the ultrapurification alternatives, reverse osmosis emerges as the most desirable option according to environmentally friendly criteria. Through modelling based on membrane transport equations and mass balances, different integrated reverse osmosis membrane cascades have been previously optimized. All the optimal solutions were characterized by the maximum allowed values for the applied pressures in the reverse osmosis stages, corresponding to the highest energy consumption and the lowest energy productivity (expressed as economic profit of the process for each unit of energy consumed). In this work, the energy productivity of the process was maximized and the optimal operation conditions were those with minimum applied pressures. However, under those conditions the membrane area required increased and the membrane productivity (expressed as economic profit of the process for each unit of membrane area employed) decreased. Therefore, multi-objective optimization was formulated to maximize simultaneously the productivities of both resources (energy and membranes).
Mostrar más [+] Menos [-]Can pollution bias peatland palaeoclimate reconstruction? Texto completo
2012
Payne, R.J. | Mitchell, E.A.D. | Hung Nguyen-Viet | Gilbert, D.
Peatland testate amoebae are widely used to reconstruct paleohydrological/climatic changes, but many species are also known to respond to pollutants. Peatlands around the world have been exposed to anthropogenic and intermittent natural pollution through the late Holocene. This raises the question: can pollution lead to changes in the testate amoeba paleoecological record that could be erroneously interpreted as a climatic change? To address this issue we applied testate amoeba transfer functions to the results of experiments adding pollutants (N, P, S, Pb, O3) to peatlands and similar ecosystems. We found a significant effect in only one case, an experiment in which N and P were added, suggesting that pollution-induced biases are limited. However, we caution researchers to be aware of this possibility when interpreting paleoecological records. Studies characterising the paleoecological response to pollution allow pollution impacts to be tracked and distinguished from climate change.
Mostrar más [+] Menos [-]The plant family Brassicaceae
2012
Anjum, Naser A.