Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Mais filtros

Intervalo de ano de publicação
Chemosphere ; 248: 125946, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32014636


Sediments from coal mine drainages (CMDs) contain large quantities of suspended pollutants (possibly numerous chemical substances) along with sulfates and hazardous elements (e.g., chromium, zinc, copper, lead) that irreversibly accumulate in the water. As this accumulation can continue for decades after discontinuation of coal extraction, it is necessary to employ multidisciplinary approaches to control the threat in such zones. The quantity of amorphous material in some CMDs was evaluated by X-ray powder diffraction (XRD) using the Rietveld-based SIROQUANT software package. Modern Dual Beam Focused Ion Beam (FIB), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscope (H-TEM), and energy-dispersive X-ray spectrometer (EDS) were used to evaluate the occurrence and transformation of nanophases (NPs). FIB is used to determine the 3D distribution of different species (internal structure) within individual NPs, whereas EDS is used to observe NP features (e.g., shape, constituent, range, assembly, and form of polymerization). The mineralogy of the sediment from the Brazilian CMDs, including the proportions of quartz, clays, Al-Fe-oxides, and amorphous NPs, appears to be related to the nature of the mineral matter in the relevant coal cleaning rejects (CCRs). The sediments of CMDs from the Brazilian coal area derived at a lower-pH range have different amorphous compositions as compared to those derived at a higher pH range. These special amorphous compositions are shown to be related to several other sediment properties such as particle surface area. The information gleaned in this study will be useful for further geochemical evaluation of CMDs in other parts of the world.

Chemosphere ; 239: 124776, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31526988


Modern microscopy studies are capable of revealing ultra-fine particles (UFPs) and nanoparticles (NPs) that are produced in the processes related to traffic vehicular, industrial, metropolitan, and marine aerosol dry deposition in the coastal zones. Especially, secondary aerosol passages complexes categories of NPs and UFPs, which can be accumulated on construction compounds and by dry deposition, encourages multiples monuments deterioration routes. The advanced electron microscopies method is one of the most utilized in environmental studies. Between the different industrial areas in the world, the Caribbean area is the most relevant symbols of air quality due to climatic conditions with strong winds, but this study shows that regionally the most industrialized region does not have an adequate air quality. In the present work, electron microscopy analyses are used to describe of the extent of ultra-fine particle and nanoparticles in walls in contact to weathering. Numerous phases were recognized by advanced mineralogy methods. Thanks to the new analytical procedure it was feasible to understand NPs and UFPs; the occurrence of potential hazardous elements (PHEs), most of them as minerals but also combined in multiple accumulations with Al-Cr-Fe-K-Mg-Pb-Si-Ti-Zn amorphous; and carbonaceous phases.

Poluentes Atmosféricos/análise , Nanopartículas/análise , Material Particulado/análise , Aerossóis/análise , Poluentes Atmosféricos/química , Poluição do Ar/análise , Atmosfera , Região do Caribe , Colômbia , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Desenvolvimento Industrial , Minerais/análise , Veículos Automotores , Material Particulado/química , Vento
Rev. luna azul ; 45: [227]-[251], octubre 20, 2017.
Artigo em Espanhol | LILACS | ID: biblio-997436


El presente artículo es resultado de un proyecto de investigación interinstitucional entre sector público, academia y sector privado, cofinanciado por recursos públicos de una convocatoria en buen gobierno. Las principales variables de análisis son la gobernabilidad y la gestión del riesgo costero en Colombia, por lo que se busca establecer una herramienta metodológica para optimizar la gestión pública en los municipios costeros. Se emplearon técnicas cualitativas y categorías de investigación de tipo propositivo, con marcadas etapas exploratorias, descriptivas y analíticas. Las técnicas más recurrentes fueron la revisión documental, las sesiones en profundidad, las entrevistas y las matrices cualitativas. Como resultado se obtienen cuatro indicadores para medir la gestión del riesgo como factor de gobernabilidad: conocimiento del riesgo, medidas de reducción del riesgo, capacidad de respuesta institucional a emergencias y coordinación y cooperación interinstitucional. Los indicadores fueron estructurados de acuerdo con una pirámide conformada por cuatro niveles (indicador, sub-indicador, variables y dato). Como producto final se crean las hojas metodológicas de cada indicador, los cuales pueden ser medidos en modo normal o modo emergencia. Se concluye que la batería de indicadores diseñada es una ventana de oportunidad para el manejo de un problema público, siendo a la vez una herramienta útil para propiciar mejoras en la gobernabilidad.

This article is the result of an interinstitutional project between the public sector, the academia and the private sector, financed jointly by public resources of a governmental research call. The main variables of analysis are governance and coastal risk management in Colombia which is why it is sought to establish a methodological tool to optimize public management in coastal municipalities. Qualitative techniques and research categories of propositional type with marked exploratory, descriptive and analytical stages were used. The most recurrent techniques were documentary review, in-depth sessions, interviews and qualitative matrices. As a result, four indicators were obtained for measuring risk management as a factor of governance: risk awareness, risk reduction measures, institutional capacity for emergency response, and interinstitutional coordination and cooperation. The indicators were structured according to a pyramid made up of four levels (indicator, sub-indicator variables and data). As a final product, methodological sheets for each indicator were designed, which can be measured in normal mode or emergency mode. It is concluded that the battery of indicators designed is a window of opportunity to manage a public problem, being at the same time a useful tool to promote improvements in governance.

Conservação dos Recursos Naturais