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Browsing by Author "Wolterbeek, H. Th."

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  • Biomarkers of exposure to metal dust in exhaled breath condensate: methodology optimization
    Publication . 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, Teresa
    In 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.
    2013Journal article Open access Show more
  • Particulate matter analysis in indoor environments of urban and rural primary schools using passive sampling methodology
    Publication . 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).
    2014Journal article Open access Show more