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  • Author or Editor: M. Almeida-Silva x
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Abstract  

A biomonitoring study, using transplanted lichens Flavoparmelia caperata, was conducted to assess the indoor air quality in primary schools in urban (Lisbon) and rural (Ponte de Sor) Portuguese sites. The lichens exposure period occurred between April and June 2010 and two types of environments of the primary schools were studied: classrooms and outdoor/courtyard. Afterwards, the lichen samples were processed and analyzed by instrumental neutron activation analysis (INAA) to assess a total of 20 chemical elements. Accumulated elements in the exposed lichens were assessed and enrichment factors (EF) were determined. Indoor and outdoor biomonitoring results were compared to evaluate how biomonitors (as lichens) react at indoor environments and to assess the type of pollutants that are prevalent in those environments.

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Abstract  

Harbour activities such as loading, unloading and transport of materials may be an important source of Atmospheric Particulate Matter (APM). Depending on the materials, the type of operation and the meteorological conditions, these activities may have an impact on the levels of APM around harbour areas. The aim of this work was to characterize the emissions of dust providing from operations associated with phosphorite handling in harbours. Phosphorite is a non-detrital sedimentary rock which contains high amounts of phosphate bearing minerals and is used for the production of phosphorous based fertilizers. When handled in harbours frequently cause visual and environment impacts due to its physical and chemical characteristics. The techniques Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission were applied as sensitive analytical tools for the determination of heavy metals and rare earth elements in phosphorite and in the APM sampled in the harbour during the unloading operations. Results showed that manipulation of phosphorite during harbour operations resulted in high emissions of particles, principally from the coarse fraction. These emissions were enriched in rare earth elements and heavy metals and were very affected by the provenience of the phosphorite.

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Abstract  

The growing concern about air quality in harbours is a result of the high impact of the operations on human health and environment. Harbour activities such loading, unloading and transport of dusty materials are important emission sources of Atmospheric particulate matter (APM). The assessment of these fugitive emissions is a difficult task because they depend on the materials, the type of operation and the meteorological scenarios. The main objectives of this work were (1) to evaluate if the techniques k0-based Instrumental neutron activation analysis (k0-INAA) and Particle induced X-ray emission (PIXE) are suitable techniques to assess fugitive emissions in harbours and (2) to estimate the impact of harbour activities on APM levels and composition. Several experimental campaigns were carried out in a Portuguese harbour, during unloading operations of fertilizer and phosphorite provided from Syria and Morocco. PM2.5 and PM2.5–10 were collected, in polycarbonate filters, by Gent samplers. The techniques k0-INAA and PIXE were applied as sensitive analytical tools to perform a complete chemical characterization of the collected samples. Results showed that manipulation of these materials during harbour operations resulted in high emissions of particles, principally from the coarse fraction. These emissions were very affected by the granulometry and nature of the handled materials. Fertilizer emissions were characterized by high concentration of Ca, P, K, Cr, Br and Zn, whereas phosphorite handling contributed principally for the increase of Ca, P and Cr levels.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Almeida, C. Ramos, A. Marques, A. Silva, M. Freitas, M. Farinha, M. Reis, and A. Marques

Abstract  

The objective of this paper was to assess the air pollution and the main sources of Air Particulate Matter in the Setúbal urban/industrial area, Portugal. PM2.5 and PM2.5–10 were sampled in Nuclepore filters and lichens transplants were exposed during 9 months. The levels of elements in these two matrixes were measured by INAA and PIXE. A large data base was created and source apportionment was performed by using Principal Component Analysis. The results showed that the main sources of fine particles were anthropogenic and were related with traffic and local industry. There was an important contribution of natural sources, mainly for the coarse fraction, associated with the sea and the soil. Lichens characterization and mapping showed that different site-specific characteristics controlled the spatial distribution of different elements. This study showed that biomonitoring is an effective complementary method to traditional sampling systems.

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Summary  

An approach for half-life determination using the reference source method associated with gamma-spectrometry with a Ge detector is presented. The method reduces the contribution of the type B component of the total uncertainty. The independence of the method regarding the instrumental interferences or radiochemical impurities was evidenced. However, there are some limitations when the method is applied for a genetically-related impurity with the same or very similar energy to that of the radionuclide to be measured, e.g., if 99Mo in a 99mTc sample is present. The measured half-life values are in good agreement with those of the literature and the associated uncertainties are lower than 0.1%.

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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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Journal of Thermal Analysis and Calorimetry
Authors: M. Dantas, A. Almeida, Marta Conceição, V. Fernandes Jr, Iêda Santos, F. Silva, L. Soledade, and A. Souza

Abstract  

This work presents the characterization and the kinetic compensation effect of corn biodiesel obtained by the methanol and ethanol routes. The biodiesel was characterized by physico-chemical analyses, gas chromatography, nuclear magnetic resonance and thermal analysis. The physico-chemical properties indicated that the biodiesel samples meet the specifications of the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP) standards. The analyses by IR and 1H NMR spectroscopy indicated the ester formation. Gas chromatography indicated that biodiesel was obtained with an ester content above 97%. The kinetic parameters were determined with three different heating rates, and it was observed that both the methanol and ethanol biodiesel obeyed the kinetic compensation effect.

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Journal of Thermal Analysis and Calorimetry
Authors: Ana Luiza Ribeiro de Souza, Tatiana Andreani, Fernando M. Nunes, Douglas Lopes Cassimiro, Adélia Emília de Almeida, Clóvis Augusto Ribeiro, Victor Hugo Vitorino Sarmento, Maria Palmira Daflon Gremião, Amélia M. Silva, and Eliana B. Souto

Abstract

Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this article, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential (ZP) were 500 nm and −34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography, were 99.06 ± 0.3 and 17.48 ± 0.05, respectively. Effective incorporation of PZQ into the particles was confirmed by small angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room temperature (25 °C) and at 4 °C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days. Results showed a relatively long-term physical stability after storage at 4 °C, without drug expulsion.

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