Assessment of the elemental content in atmospheric particulate from Córdoba, Argentina, by Total Reflection X-ray Fluorescence using Synchrotron radiation

CARRERAS, H.; WANNAZ, E.; PEREZ, CARLOS; PIGNATA, M.L.

Campinas, Brasil

Workshop; 16 Reunión Annual de Usuarios LNLS; 2006

Laboratorio Nacional de Luz Sincrotron

The levels of atmospheric particulate in urban environments are often well above natural background levels. They have a strong impact on the environment and represent an important risk to human health. Emission, composition, and kinetics of atmospheric particulate are regionally very different. Therefore, the investigation of regional situations is very important in order to understand and interpret the exposure situation. The main aim of the present study was to analyze the composition of atmospheric particulate collected in Córdoba and to estimate the emission sources. Another important goal was to assess the perfomance of the lichen \it{Usnea amblyoclada} as a bioaccumulator of atmospheric particulate. PM H$_{10}$O  was collected with a medium volume sampler on glass fiber filters during six months, in Córdoba city. The filters were then accurately digested with a mixture of HNO H$_{3}$O :HCl:HFl. The resulting material was separated by centrifugation, recovered in 10 ml of Milli Q water and 100 $\mu$l of Ge were added as an internal standard. Lichen material was reduced to ashes and prepared in the same way. Alicuots of 5 $\mu$l from each solution were dried on an acrylic support. X-ray fluorescence with synchrotron radiation total reflection was used to analyze the elemental composition of the particulate collected both, on filters and on lichen thalli. Factor analysis was applied in both data sets. Almost 71 % of the variability of atmospheric particulate can be explained by 4 factors. The first factor can be associated with industrial emissions, together with Sr that might have other emitting sources; factor 2 has association with foundries emissions; factor 3 associates with soil dust and factor 4 is represented by vehicular emmisions. The same analysis performed on lichens data reveals a good correspondence with filters data. However, the clustering with filters and with lichens data, suggest that during the winter period the correspondence between filters and lichen is better achieve than in summer-autumm periods. The results obtained allow us to determine the composition of the atmospheric particulate in urban areas from Cordoba city and to identify the emission sources. Besides, it was possible to prove that the lichen \it{U. amblyoclada} can be employed in biomonitoring programs as its elemental composition is in good accordance with atmospheric particulate data obtained from filters.