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Abstract  

Chemical elements were determined in epiphytic lichens from Terceira and Santa Maria islands (Azores, Portugal), by k 0-standardized, instrumental neutron activation analysis. Abundance ranges were generally below those in mainland Portugal, except for Br (Terceira), Cl (Santa Maria), Na (Santa Maria), and Se (both islands). Elemental (averaged) contents of As, Br, Cl, Co, Cr, Mg, Na, Se, Hg and Zn were significantly different between the islands. Anthropogenic influence was discernible in Terceira if not in Santa Maria, where only crustal and marine sources are apparent.

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Abstract  

A new Compton suppression system (CSS) for the gamma-ray spectrometer portion of the neutron activation analysis (NAA) was set up at the RPI/ITN. The pneumatic transfer system, SIPRA, for short-lived nuclides and cyclic irradiations was improved. A full calibration procedure of the CSS and SIPRA systems was performed. Two certified reference materials, NIST-SRM-1572 (Citrus Leaves) and NIST-SRM-1633a (Coal Fly Ash) were analyzed using the calibration factors. The CSS was instrumental in lowering the detection limits of Cr, Fe, Hg, Rb, Sr, Th and Zn by reducing background and/or spectral interference considerably. The analytical results were evaluated by comparison to the NIST certified values with deviations ranging from 2% to 8% for the above mentioned elements, except Zn ranging from 10% to 15% for biological and environmental samples, respectively.

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Abstract  

This study intended to demonstrate the use of k 0-IAEA software with the NAA#3 irradiation hole in the HANARO research reactor and the gamma-ray spectrometers at the NAA laboratory in the Korea Atomic Energy Research Institute (KAERI). NIST SRM 2586-Soil was chosen as a sample to validate the analytical protocol by using the k 0-IAEA software. Twenty four elements were determined and the resultant deviations between the experimental results and the certified values were all within 10% except for Dy. In addition, an analysis of three types of synthetic multielement standards (SMELS) prepared by the Institute for Reference Materials and Measurements (IRMM) and Institute of Nuclear Science (INW) in Belgium was executed. The analytical results agreed well with the assigned values and the U-scores for most of the elements were lower than 2.

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Abstract  

This study aims to find out a vascular plant species that accumulate relatively high concentrations of arsenic (As) for its use as phytoremediator at abandoned and contaminated mining areas, such as São Domingos mines (Portugal). The assessment of As contamination levels in soils and plants of other similar sites in the north of the country (Castromil and Poço de Freitas) was also conducted; and the sample analyses were made by instrumental neutron activation analysis. Agrostis genera have shown higher As transfer coefficients than other studied plant species and, in particular, Agrostis curtisii has shown a reasonable ability to accumulate high concentration of this toxic element.

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Abstract  

Different methodologies of neutron activation analysis (NAA) are now available at the Technological and Nuclear Institute (Sacavém, Portugal), namely Compton suppression, epithermal activation, replicate and cyclic activation, and low energy photon measurement. Prompt gamma activation analysis (PGAA) will be implemented soon. Results by instrumental NAA and PGAA on environmental and nutritional samples are discussed herein, showing that PGAA — carried out at the Institute of Isotope Research (Budapest, Hungary) — brings about an effective input to assessing relevant elements. Sensitivity enhancement in NAA by Compton suppression is also illustrated. Through a judicious combination of methodologies, practically all elements of interest in pollution and nutrition terms can be determined.

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Abstract  

The main objective of this study is the elemental characterization of geomaterial samples (“soils” and Rañas), collected between 2007 and 2008, in the Morais Massif, (NE Mainland of Portugal) by using two complementary techniques: instrumental neutron activation analysis (INAA) and high resolution gamma spectrometry. Samples granulometric fractions lower than 63 μm were analyzed by gamma spectrometry, for artificial and natural radionuclides using HPGe detectors and by INAA, for chemical elements at the Portuguese research reactor, RPI. Statistical analysis, such as clusters analysis and Pearson correlations were applied to the obtained results. The enrichment factors were also calculated as an estimator of anthropogenic inputs in relation to the average crustal abundance. Group differentiation of Rañas and “soils” is clearly shown from cluster analysis. The strong correlation factors obtained between some chemical elements corroborates the origins and the geology/mineralogy of the area studied. The combined application of both nuclear analytical techniques has shown their importance in providing useful information for the future site and repository performance and safety assessment studies.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Almeida, M. Freitas, C. Repolho, I. Dionísio, H. Dung, C. Pio, C. Alves, A. Caseiro, and A. Pacheco

Abstract  

Recent health studies evidence that epidemiological studies must be combined with accurate analyses of the physico-chemical properties of the particles in order to determine the effects of atmospheric aerosols on human health. The project “Atmospheric Aerosol Impacts on Human Health” focuses on the chemical characterization of PM2.5 aerosols with the aim to analyze the health risks associated with exposure to aerosols and understand how their chemical composition contributes to the toxicity and human health problems traditionally associated with fine particles. During one year, PM2.5 was collected daily, with a Partisol sampler, in the centre of Lisbon. The aerosols were analyzed by Neutron Activation Analysis and Ion Chromatography in order to determine their chemical composition. In parallel the clinical situation of students from the schools situated around the sampler was followed. The incidence of asthma and rhinitis episodes was registered. Results showed that students were exposed to PM2.5 concentrations that exceed the World Health Organization recommended levels. A marked sea influence in the aerosol characteristics was identified by the use of air masses trajectories and by the concentrations of chloride, sodium and magnesium.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Almeida, M. Freitas, C. Repolho, I. Dionísio, H. Dung, A. Caseiro, C. Alves, C. Pio, and A. Pacheco

Abstract  

The goal of this research is to determine trends and sources of airborne particulates in the centre of Lisbon, by using speciated particulate-matter data and back-trajectory analyses. Results showed that, in 2007, the annual PM2.5 concentration exceeded the World Health Organization recommended levels. PM2.5 diurnal variability and the ratio between weekdays’ and weekends’ concentrations indicated that traffic contributed highly to decreasing air quality. Air back-trajectory analysis showed that maritime air mass transport had a significant role on air quality in Lisbon, promoting the decrease of anthropogenic aerosol concentrations.

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Abstract  

The number of children reporting rhinitis by month is compared with air pollutant concentrations in Lisbon, where they live and attend school. INAA, ionic exchange chromatography and data accessed through the internet were statistically processed with the children rhinitis data. Association between rhinitis and atmospheric variables are processed using Spearman non-parametric statistics and principal component analysis. It is pointed out that traffic, soil resuspension from traffic, meteorological conditions, and industry air pollutants contribute to respiratory trends. Ir (Pt group), a vehicle catalyst, may have some contribution.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: N. Canha, M. Freitas, M. Almeida-Silva, S. Almeida, H. Dung, I. Dionísio, J. Cardoso, C. Pio, A. Caseiro, T. Verburg, and H. Wolterbeek

Abstract  

One Plus Sequential Air Sampler—Partisol was placed in a small village (Foros de Arrão) in central Portugal to collect PM10 (particles with an aerodynamic diameter below 10 μm), during the winter period for 3 months (December 2009–March 2010). Particles masses were gravimetrically determined and the filters were analyzed by instrumental neutron activation analysis to assess their chemical composition. The water-soluble ion compositions of the collected particles were determined by Ion-exchange Chromatography. Principal component analysis was applied to the data set of chemical elements and soluble ions to assess the main sources of the air pollutants. The use of both analytical techniques provided information about elemental solubility, such as for potassium, which was important to differentiate sources.

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