Browsing by Author "Almeida, S. M."
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- Biomarkers of exposure to metal dust in exhaled breath condensate: methodology optimizationPublication . Félix, P. M.; Franco, C.; Barreiros, M. Alexandra; Batista, B.; Bernardes, S.; Garcia, S. M.; Almeida, A. B.; Almeida, S. M.; Wolterbeek, H. Th.; Pinheiro, TeresaIn occupational assessments where workers are exposed to metal dust, the liquid condensate of exhaled breath (EBC) may provide unique indication of pulmonary exposure. The main goal of this study was to demonstrate the quality of EBC to biological monitoring of human exposure. A pilot study was performed in a group of metal dust–exposed workers and a group of nonexposed individuals working in offices. Only metal dust–exposed workers were followed along the working week to determine the best time of collection. Metal analyses were performed with inductively coupled plasma mass spectrometry (ICP-MS). Analytical methodology was tested using an EBC sample pool for several occupationally exposed metals: potassium, chromium, manganese, copper, zinc, strontium, cadmium, antimony, and lead. Metal contents in EBC of exposed workers were higher than controls at the beginning of the shift and remained augmented throughout the working week. The results obtained support the establishment of EBC as an indicator of pulmonary exposure to metals.
- Exhaled breath condensate as a biomonitor for metal exposure: a new analytical challengePublication . Barreiros, M. Alexandra; Pinheiro, Teresa; Félix, P. M.; Franco, C.; Santos, Mário João dos; Araújo, F.; Freitas, Maria do Carmo; Almeida, S. M.The study of exhaled breath condensate (EBC) obtained by cooling exhaled air under conditions of spontaneous breathing is considered one of the areas with higher interest in respiratory health research. The use of EBC for elemental determination in occupational exposure requires a standard methodological procedure to implement its practice in occupational studies. EBC is an inhomogeneous sample with organic and particulate matter in suspension, which may hamper analytical results reliability. Total reflection X-ray fluorescence and inductive coupled-plasma mass spectrometry (ICP-MS) techniques were chosen as both are multielemental, require small sample volumes and have appropriate detection limits. Estimation of the overall uncertainty in both techniques was carried out using a pool of EBC collected from a group of workers of a lead processing industry to perform precision and trueness studies for K, Mn, Cu, Cd, Sb and Pb. Precision was estimated in terms of repeatability using the native EBC sample pool and trueness in terms of recovery obtained from spiking aliquots of the EBC pool with K, Mn, Cu, Cd, Sb and Pb at different concentrations. Recovery was the most significant contribution to total uncertainty. The overall uncertainties obtained for ICP-MS enabled to discriminate between groups of individuals exposed to different levels of contaminants. Therefore EBC proved to be useful in human biomonitoring.
- Indoor air quality in primary schoolsPublication . Freitas, Maria do Carmo; Canha, Nuno; Martinho, Maria; Almeida-Silva, Marina; Almeida, S. M.; Pegas, Priscilla; Alves, Célia; Pio, Casimiro; Trancoso, Maria Ascensão; Sousa, Rita; Mouro, Filomena; Contrira, Teresa
- Particulate matter analysis in indoor environments of urban and rural primary schools using passive sampling methodologyPublication . Canha, Nuno; Almeida, S. M.; Freitas, Maria do Carmo; Trancoso, Maria Ascensão; Sousa, Rita; Mouro, Filomena C.; Wolterbeek, H. Th.Passive sampling methodology was applied to collect particulate matter (PM) in classrooms of urban and rural primary schools. The samples were taken during a year by passive deposition allowing the study of seasonal variability of the particles masses and chemical content.Chemical characterization of the collected particleswas performed in order to measure its soluble ions content and elemental composition. To identify the main polluting sources, correlations between parameters and enrichment factors were studied. Higher particle masses concentrations were registered in autumn, with a mean of 1.54 0.74 mg day1 cm2. The major element in the collected particles was calcium, representing 63e73% of the analyzed mass of the particles inside the urban classrooms. In the rural cluster, calcium remained the major component but with a slight lower contribution to the overall particles composition (42e46%). The calcium source was hypothesized to be the chalk used in the blackboards of the classrooms due to a strong correlation found between Ca2þ and SO4 2 . Soil re-suspension, traffic and other anthropogenic emission sources were also identified. Analysis showed enrichment of the particles with Br, Ca, Zn and Sb in the urban cluster and enrichment of the same elements, except for Ca, in the rural cluster. The comparison between the results from both clusters allowed the identification of classrooms with higher particles concentrations that can indicate potential indoor air quality problems (reflected by an indoor accumulation of pollutants).