Search

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. [ABSTRACT FROM AUTHOR]

The article reports on the study conducted on temporomandibular disorders (TMD) among stress-free patients. An evaluation is conducted on the temporomandibular joints (TMJs) of forty stress-free patients during clinical evaluation and magnetic resonance imaging. The result of the study shows that TMD is less likely to develop among stress-free patients.

Abstract: A chemical characterization was carried out for PM2.5 and PM2.5–10 samples collected in a suburban area and the concentrations of 12 elements were determined in 8 size segregated fractions using a Berner Impactor. Two main objectives were proposed in this work: 1) to test for closure among chemical and gravimetric measurements of PM2.5 and PM2.5–10 and 2) evaluate the performance of Multilinear Regression Analysis (MLRA) and Mass Balance Analysis (MBA) in the determination of source contribution to Particulate Matter (PM) concentrations. The fraction unaccounted for by chemical analysis comprised on average 17% and 34% of gravimetric PM2.5 and PM2.5–10, respectively. The lack of closure in PM2.5 and PM2.5–10 mass (i.e., constituent concentrations not adding up to gravimetrically measured) could partly result from the presence of water associated with particles and errors in the estimation of unmeasured species. MLRA and MBA showed very similar results for the temporal variation of the source contributions. However, quantitatively important discrepancies could be observed, principally due to the lack of mass closure in PM2.5 and PM2.5–10. Both methods indicated that the major PM2.5 aerosol mass contributors included secondary aerosol and vehicle exhaust. In the coarse fraction, marine and mineral aerosol contributions were predominant. [Copyright &y& Elsevier]

Abstract: Three objectives were proposed in this work: (i) to evaluate the concentrations of Air Particulate Matter (APM) species obtained via k 0-INAA and PIXE by comparison with results obtained via classical methodologies, (ii) to study the water solubility of chloride, sodium, sulfur, potassium and calcium sampled in APM filters and (iii) to analyze the importance of their solubility in the identification of emission sources. The multi-technique analytical approach, using nuclear and classical techniques, not only the results provided for a large number of APM species (essential for source apportionment studies) but also, for several elements, independent methods gave information about their solubility. Results indicated that: (1) the total Cl concentration was lower than the soluble Cl− concentration, showing that it volatilized partially during the PIXE analysis, (2) the majority of Na—provided mainly from sea salt spray—was soluble, (3) in PM10 most of the sulfur was in SO4 2− chemical form, (4) K exhibited aweaker solubility in the coarse fraction: in PM10−2.5, the insoluble potassium was associated with the mineral aerosol, whereas the soluble fraction resulted from the sea salt spray, (5) Ca showed a lower solubility in the coarse fraction, and the insoluble Ca was associated with a mineral origin. [Copyright &y& Elsevier]

The analysis of airborne particulate matter (APM) by k0-NAA was assessed using: (1) BCR reference material (RM) simulated air-filters, (2) synthetic air-filters prepared by spiking blank filters with standard solutions, and (3) real APM filters. k0-INAA is a suitable technique for the analysis of APM, delivering accurate and precise results. However, the quality assessment of APM analysis appears to be a difficult task. [ABSTRACT FROM AUTHOR]

The Portuguese Research Reactor (RPI) is a 1 MW swimming pool type reactor, operating since the early 1960s. The fuel is MTR type, with flat plates of U-Al alloy enriched to 93% in 235U. As the core configuration changed in April 2000, it became essential to characterise the neutron field in the most useful irradiation positions of RPI, in order to guarantee the accuracy in the application of k0-neutron activation analysis (k0-NAA). Experimental values of the thermal to epithermal neutron flux ratio (f) and of the deviation of the epithermal neutron spectrum from the 1/E shape (a) were determined using the “Cd-ratio for multi-monitor' method. The neutron temperature (Tn) was obtained from co-irradiation of Lu with “1/v' monitors. The results for several irradiation positions are presented and discussed in this work. Some element concentrations are determined based on the parameters obtained in this work, and compared with the certified reference material concentrations. [ABSTRACT FROM AUTHOR]

Examples of the application of k0 standardized instrumental neutron activation analysis (k0-INAA) to aerosols and biological monitors in the last 10 years at Instituto Tecnológico e Nuclear (ITN) are given. As an analytical technique, INAA, in association with the k0 method was applied to these materials in four different projects, aiming at monitoring concentrations of heavy metals and others elements in the atmosphere in the Portuguese territory. In these studies we analysed the lichen Parmelia sulcata Taylor and olive tree bark as monitors as well as aerosol samples. For each project some representative results are presented, followed by a discussion of the application of this technique to environmental studies. [ABSTRACT FROM AUTHOR]

Abstract: Foundry industry has important environmental and occupational health impacts. More information is needed to properly assess occupational health risks presented by this industrial sector. This works aims at (1) characterizing the workers exposure to particulate matter in the foundry industry using k 0-Instrumental Neutron Activation Analysis (k 0-INAA) and Particle-Induced X-Ray Emission (PIXE) and (2) identifying some weakness of the k 0-INAA technique when high concentrations of particulate matter and metals are involved. Filters were collected in a foundry industry which processes Pb and were analysed by k 0-INAA and PIXE. In INAA, the incomplete deposition of gamma-rays in the germanium crystal due to Compton scattering elevated the spectra baseline, thus increased the background, and hindered the identification of some photopeaks. The problem was particularly important due to the high Sb contents existing in the sampled filters. The application of the Compton Suppression System for the analysis of these filters was successfully used in order to ascertain potential improvements on the detection limits for Zn and Fe. Results obtained showed that in this foundry industry workers were exposed to high concentrations of Pb, Sb, Fe, Sn, As, Ni, Br, Na and Cl. [Copyright &y& Elsevier]

Abstract: The current study presents, for the first time, a long-term organic speciation of aerosol at the Cape Verde archipelago. The Cape Verde location, in the Atlantic Ocean, provides a unique laboratory to study background aerosol, long-range transport, aerosol mixing with mineral dust, biomass burning and sea surface components. In order to contribute to a better understanding of this environment, a one-year long measurement campaign was performed in Praia City, Santiago Island. PM10 concentrations (20.5–370 μg/m3) and the organic composition of PM10 were influenced by the African dust influxes. The carbonaceous content of PM10 was very low, suggesting that most of the mass has mineral origin. The PM10 composition was essentially characterised by a large variety of organic compounds, which can be grouped into general compound classes, such as n-alkanes, n-alkanols, n-acids and sugars. The n-alkane total concentrations varied from 3.77 to 53.2 ng/m3. The n-alkanols distribution showed a significant biogenic contribution whether from microbial origin or from epicuticular plants during African dust outbreaks. The total concentrations of n-alkanoic acids varied from 0.011 to 4.51 ng/m3. The lower n-alkenoic acids content, obtained during the periods of long-range transport from Africa, indicated a more aged aerosol. The monosaccharide anhydrides were detected in all samples with a range of concentrations from 2.06 to 12.7 ng/m3. [Copyright &y& Elsevier]

Abstract: The quality control (QC) and performance evaluation for the k 0-based neutron activation analysis (k 0-NAA) at the Portuguese research reactor (RPI) has been developed with the intention of using the method to meet the demands of trace element analysis for the applications in environmental, epidemiological and nutritional studies amongst others. The QC and performance evaluation include the following aspects: (1) estimation of the overall/combined standard uncertainty from the primary uncertainty sources; (2) validation of the method using a synthetic multi-element standard (SMELS); and (3) analysis of the certified reference materials from the National Institute of Standards and Technology (USA): NIST-SRM-1633a and NIST-SRM-1648 and the reference material from the International Atomic Energy Agency: IAEA-RM-336, for the purpose of controlling the overall accuracy and precision of the analytical results. The obtained results revealed that the k 0-NAA method established at the RPI was fit for the purpose. The overall/combined standard uncertainty was estimated for elements of interest in the intended applications. The laboratory’s analytical results as compared to the assigned values with the bias were less than 12% for most elements, except for a few elements which biased within 13–18%. The u-score values for most elements were less than |1.64|, except for Co, La and Ti within |1.64|–|1.96| and Sc, Cr, K and Sb within |1.96|–|2.58|. The NIST-1633a was also analyzed over 14 months for the purpose of evaluating the reproducibility of the method. The quality factors of k 0-NAA established at RPI were evaluated, proving that the method meets the requirements of trace element analysis, which is also considering the method’s performance for which the k 0-NAA affords a specific, rapid and convenient capability for the intended applications. [Copyright &y& Elsevier]