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Abstract  

Gent air samplers were used for air particulate matter sampling in Sado estuary area, separating fine and coarse fractions. Three sampling sites were chosen (Palmela, Faralhão and Tróia), inside a 15 km × 25 km area at Setúba region, 50 km south of Lisbon, Portugal. Transplants of Parmelia sulcata Taylor were suspended in nylon bags within the same area following a 2.5 km × 2.5 km grid, during the same period as the aerosol collection. Both lichen transplants and filters were analysed by k 0-INAA. This work compares MCTTFA results given by the two air pollution monitoring procedures. The main differences concern a physiological factor in biomonitors and a better definition of traffic and re-suspension by aerosols.

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Abstract  

Aerosol chemical composition data for PM2.5 and PM2.5–10 was acquired, in two sampling stations, at an industrialized area located in Sado Estuary. Two methods were used to have an insight on the origin of the particles: the comparison between the measurements obtained in the two sampling stations and the association between the wind direction and the element concentrations. Results showed that Ce, Fe, La, Sc, Sm, Na, Co and Se were associated with non-local sources whereas As, K, Sb, Zn, Hg, Br, Cr, Hf and U had a local origin.

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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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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. C. Freitas, M. M. Farinha, A. M. G. Pacheco, M. G. Ventura, S. M. Almeida, and M. A. Reis

Summary  

Selenium is determined by instrumental neutron activation analysis (INAA), based on measurement of the long-lived 75Se nuclide. In the urban and industrialized areas of Portugal selenium contents have been found of the order of of 0.5-1 ng/m3 in PM10 and PM2.5, according to the data collected since 1994. From November 12, 2001 and for not more than 3 months, the Se contents in PM10 and PM2.5 increased by a factor of 1000 in the northern area of Lisbon. More than other nutrients, selenium illustrates the dichotomy between essentiality and toxicity. There is no legislation on Se for ambient air and on indoor ambient point threshold limit values (US and Germany legislation), were 100 times higher than the abnormal values found that winter. The increase was also visible for mercury although not to such an extent. Attempts were made to understand the trend, going into a study of the emission sources located in the area using both INAA and PIXE. It was concluded that the observation occurred due to abnormal meteorological wind direction, which pushed the pollutants towards the populated area, when usually they flow into the Tagus estuary.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Freitas, M. Reis, A. Marques, S. Almeida, M. Farinha, O. de Oliveira, M. Ventura, A. Pacheco, and L. Barros

Abstract  

Examples of the application of k 0 standardized instrumental neutron activation analysis (k 0 -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 k 0 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.

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