9,312 research outputs found
Waste management in Portugal and Europe: an overview of the past, present and future
As word society has grown exponentially it was created more and more wastes. Each year European Union throws away 3 billion tons of waste, and some 90 million tons of that are hazardous. It is clear that treating and disposing of all this material - without harming the environment becomes a major trouble. In the early years 90 the amount of waste generated in Europe increased by 10%. Most of that was thrown away in incinerators, or dumped into landfill creating environmental damage. Landfill disposal not only takes valuable land space but also causes air, water and soil pollution, discharging carbon dioxide (CO2) and methane (CH4) into the atmosphere and chemicals and pesticides into the earth and groundwater. This situation is harmful to human health as well as to plants and animals. These events triggered urgency for a responsibility and appropriate legislation for correct waste management. EU and Portuguese policy main objective in the waste management are prevent and reduce waste production, and reduce their toxicity, through the reuse and modification of production processes, adopting cleaner technologies. Waste management must also avoid or at least reduce its risk to human health and to environment. In Portugal, wastes sector was suffered a revolution on the last years, due to the appearance of the Strategic Plan for Solid Waste I (PERSU I) in 1997 and by the constant pressure from the EU for their state members and waste producers. In December 2006 was created the PERSU II to correct all mistakes made in the previous plan. However soon realized that PERSU II had very ambitious goals and so unattainable that triggered the need to reformulate these objectives. The aim of this overview in waste management was to follow the goals outlined in PERSU II, identifying the progress of each operational system over the years. It was also the target compare those results to European statistics tracing possible ways to permit compliance with EU objectives in future
Physiological response of Cistus salviifolius L. to high arsenic concentrations
Arsenic is a trace element found in the environment which can be particularly toxic to living organisms. However, some plant species such as those of the genus Cistus are able to grow in soils with high As concentrations and could be used in the sustainable rehabilitation of mining areas 19 through phytostabilization. In this work, the growth and the physiological response of Cistus salviifolius L. to As induced oxidative stress at several concentrations (reaching 30 mg L-1) in an hydroponic system were evaluated for 30 days. Several growth parameters, chlorophyll content, chemical composition, one indicator of oxidative stress (H2O2) and two of the major anti-oxidative metabolites (ascorbate and glutathione) were analyzed.
The toxic effect of As was better perceived in the plants submitted to treatments with concentrations of 20 and 30 mg As L-1. Plants subjected to these treatments had higher concentration of As in roots and shoots. The concentrations of Ca, Mg, K and Fe in the plants, as well as a large part of the evaluated growth parameters were also affected. Arsenic did not interfere with the ability of the plant to perform photosynthesis, as there were no significant differences in the contents of chlorophyll a, b and total between the different treatments. Plants from all treatments accumulated higher amount of As in roots than in shoots, and it was also in the roots that the concentrations of H2O2, AsA and GSH were higher. Cistus salviifolius showed high tolerance to As up to the concentration of 5 mg L-1, which makes it a species with high potential to be used in the phytostabilization of soils contaminated with As and presenting high concentrations of the element in the soil solution.info:eu-repo/semantics/acceptedVersio
Development of a hybrid dextrin hydrogel encapsulating dextrin nanogel as protein delivery system
Dextrin, a glucose polymer with low molecular weight, was used to develop a fully resorbable hydrogel, without using chemical initiators. Dextrin was first oxidized (oDex) with sodium periodate and then cross-linked with adipic acid dihidrazide, a nontoxic cross-linking molecule. Furthermore, a new bidimensional composite hydrogel, made of oxidized dextrin incorporating dextrin nanogels (oDex-nanogel), was also developed. The oDex hydrogels showed good mechanical properties and biocompatibility, allowing the proliferation of mouse embryo fibroblasts 3T3 cultured on top of the gel. The gelation time may be controlled selecting the concentrations of the polymer and reticulating agent. Both the oDex and oDex-nanogel hydrogels are biodegradable and present a 3-D network with a continuous porous structure. The obtained hybrid hydrogel enables the release of the dextrin nanogel over an extended period of time, paralleling the mass loss curve due to the degradation of the material. The dextrin nanogel allowed the efficient incorporation of interleukin-10 and insulin in the oDex hydrogel, providing a sophisticated system of controlled release. The new hydrogels present promising properties as an injectable carrier of bioactive molecules. Both proteins and poorly water-soluble low-molecular-weight drugs are efficiently encapsulated in the nanogel, which performs as a controlled release system entrapped in the hydrogel matrix.V.C. and D.S. were supported by the grants SFRH/BD/27359/2006 and SFRH/BD/64571/2009, respectively, from Fundacao para a Ciencia e Tecnologia (FCT), Portugal. We thank FCT funding through PTDC and COMPETE
Relating air Pollution and Respiratory Diseases Occurrences.
info:eu-repo/semantics/publishedVersio
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