1000 resultados para Deterioro ambiental -- Colombia
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Peer-reviewed
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DDT and others organochlorine insecticides are very persistent substances. Clinical symptoms of intoxication have been reported in humans, although the main problem concerning such substances is bioaccumulation and biomagnification along throphic chains, leading to contamination of top predators and humans after them. In this review these characteristics are described, as well as some aspects of the control of vector borne diseases, like leishmaniasis and malaria, which were until recently, controlled by the health authorities using DDT.
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Defining environmental chemistry is a not an easy task because it encompasses many different topics. According to Stanley E. Manahan, author of a classical textbook of Environmental Chemistry, this branch could be defined as the one centered in the study of the sources, transport, effects and fates of chemical species in the water, soil, and air environments, as well as the influence of human activity upon these processes. More recently, new knowledge emerged from the Environmental Toxicology allowed to go even deeper in the meaning of 'effects' and 'fates' of a continuous growing number of organic and inorganic species disposed in water bodies, soils and atmosphere. Toxicity tests became an important tool to evaluate the environmental impact of such species to a great number of organisms, thus allowing to set quality criteria for drinking water, sediments and biota. The state of art shows that environmental chemistry is a multi-inter disciplinary science by nature; therefore, it needs more than a limited, unique-approach and non-oriented set of data to understand the nature of natural processes. Taking all these aspects into consideration, one can say that Environmental Chemistry in Brazil is now a well established area of research within the classical areas of the Chemistry, with a large number of emerging groups as well research groups with worldwide recognition.
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Within the scope of the TECNOLONIAL (HAR2008-02834/HIST) project, an archaeologi- cal and archaeometric research is being conduct- ed in order to clarify and systematize transport jars production in the Iberian peninsula and their distribution abroad, especially to the Americas, from the 15th to the 17th century. The production centre of Seville, in the Crown of Castile, produced large glazed and unglazed transport jars, called botijas, which were mainly devoted to the Atlantic trade network. The pres- ent study accounts for the first results obtained from an initial sample of 34 transport jars dated around the 15th-16th centuries from the produc- tion centre of Seville and the reception site of Santa María de la Antigua del Darién (gulf of Urabá, Colombia). This latter site is especially significant since it was the first Spanish founda- tion (1510) in continental America that obtained the title of town, and was the seat for the Governor of the new region called Castilla de Oro, as well as for the first diocese. All individuals were analyzed by means of x-ray fluorescence and diffraction analyses and then compared with the majolica production database from Seville. The results enabled us to define the first refer- ence groups for such modern transport jars, and to get a first insight into the jars coming to the Americas in the early 16th century whose prove- nance can be linked to Seville, but not Triana.
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The article shows how the monitoring of the water quality can be utilized in an inter-disciplinary pedagogical project involving Analytical Chemistry, Biochemistry and Microbiology making the apprenticeship more dynamic and consolidating the link between the student and the community.
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The toxic heavy metals can not be transformed in other less toxic substances as organic wastes through chemical process. Various chemistry courses at Faculty of Philosophy, Sciences and Humanities (FFCLRP/USP) use heavy metals in their experimental classes. In this context, a course were created: "Heavy Metal Wastes generated in the teaching and research laboratories: disposal or recovery" and has a specific goal to capacitate the students to define the adequate strategy for disposal or recovery of the chemical wastes, in particular heavy metals, through an interdisciplinary approaching. This course was given to 25 students during the second semester of 2000 and 2001. The environmental responsibility desired for the professional and citizen can be promoted.
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The toxicity of the major As species present in the environment justifies the effort for quantifying the element in environmental organic samples, which can vary from animal and vegetal tissues to coal and industrial residues. This paper comments about the applicability of the O2 bomb digestion, as a general procedure for all environmental organic materials. A rapid and straightforward method is suggested, which consists in burning the sample in the bomb at high O2 pressure, dissolving the vapours in diluted HNO3 and determining As in the resulting solution by atomic absorption spectrometry with electrothermal atomization. The method was applied to certified materials and plant samples.
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The occurrence and the effects of organotin compounds (OTs) have been studied since a long time, due to their widespread use and deleterious effects. Some OTs are used as pesticides in crops, or as biocides in antifouling paints, applied in the ship hulls to avoid attachment and growth of tube worms, mussels and barnacles. However, "nontarget" organisms may be exposed, resulting in the poisoning of biological system, originating mutations and sentencing species to extinction. In this work we reported a revision study on the history of OTs and the techniques developed for its assessment and control.
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Environmental education is a big challenge in this century and the University has an important role to play in it. This paper presents a practical experience of environmental education in the university teaching at the University of Bahia. That experience involves the creation of an interdisciplinary group that has been developing research and teaching activities with interdisciplinary perspectives. The paper also discusses a methodology proposed by this group aiming to include environmental education in science teaching using social and cultural approaches.
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Este artículo es una síntesis del proyecto realizado en INBio (Instituto Nacional de Biodiversidad), Costa Rica, cuyo objetivo principal fue la mejora de la Interpretación Ambiental de INBioparque, un parque temático de biodiversidad dentro de la institución. INBioparque está situado en Santo Domingo de Heredia, provincia de Heredia, Costa Rica. Éste pretende hacer una pequeña representación de los principales ecosistemas que se encuentran en el país. El parque se divide en diferentes zonas: Bosque del Valle Central, Bosque Húmedo, Bosque Seco, Humedal y Finca. En esta última, la Finca (ecosistema basado en la biodiversidad domesticada) es dónde se ha centrado todo el proyecto, debido a que presentaba una mayor necesidad de mejora en su interpretación ambiental. La Interpretación ambiental traduce el lenguaje técnico de los profesionales a términos e ideas más entendedoras para todos los públicos. Pretende promover una nueva conciencia sobre el valor de la biodiversidad, lograr su conservación y mejorar la calidad de vida del ser humano. El proyecto propone la mejora de la interpretación ambiental a través de las fichas técnicas elaboradas de las diferentes especies vegetales de la Finca, así como la renovación o creación de rótulos explicativos. Se propone también un recorrido guiado y auto guiado para hacer más entendedora la visita, además de algunas actividades y talleres.
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The objective of this paper is to analyse the existente or not of a wage curve in Colombia, paying special attention to the differences between formal and informal workers, an issue that has been systematically ignored in the wage curve literature. The obtained results using microdata from the Colombian Continuous Household Survey (CHS) between 2002 and 2006 show the existence of a wage curve with a negative slope for the Colombian economy. Using information on metropolitan areas, the estimates of the elasticity of individual wages to local unemployment rates was -0.07, a value that is very close to those obtained for other countries. However, the disaggregation of statistical information for formal and informal workers has shown significant differences among both groups of workers. In particular, for the less protected groups of the labour market, informal workers (both men and women), a high negatively sloped wage curve was found. This result is consistent with the conclusions from efficiency wage theoretical models and should be taken into account when analysing the functioning of regional labour markets in developing countries.
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In this work, a partial least squares regression routine was used to develop a multivariate calibration model to predict the chemical oxygen demand (COD) in substrates of environmental relevance (paper effluents and landfill leachates) from UV-Vis spectral data. The calibration models permit the fast determination of the COD with typical relative errors lower by 10% with respect to the conventional methodology.
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The main environmental impacts related to the gravel pits in the medium course of the Fluvià river have been assessed. In order to compute the global impact and index based on the numerical values of different impacts has been defined. This index is applied to different areas and the results reveal that the environmental impact expected for a gravel pit is high or moderate close to the main streams and low in the rest of the territory
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Article que reflexiona sobre la importància del pati escolar, i com aquests poden contribuir a l’educació ambiental dels infants
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Sugar cane cultivation in the State of São Paulo has expanded in the last years, with an annual production of 20010(6) t in an area of 2.5 10(6) hectares. The use of herbicides, pesticides and fertilizers in sugar cane plantations, together with deforestation of riparian vegetation, have caused impacts on the hydric resources of the adjacent areas. The aim of this work is to evaluate the influence of sugar cane plantations on streams in the central region of the State of São Paulo, studying 16 organochlorinated compounds and 7 metals (Cu, Fe, Cd, Zn, Mn, Cr and Ni) found in the sediments of 11 streams. The results show that there is a higher concentration of metals and organochlorinated compounds in streams without riparian vegetation when compared to forested areas.