Molybdenum and uranium from remote continental origin at Pico summit, Pico island, Azores, Portugal


Freitas M. d. C. , Pacheco A. M. G. , Tuncel G.

8th International Symposium on Natural Radiation Environment, Buzios, Brezilya, 7 - 12 Ekim 2007, cilt.1034, ss.234-235 identifier

  • Cilt numarası: 1034
  • Basıldığı Şehir: Buzios
  • Basıldığı Ülke: Brezilya
  • Sayfa Sayıları: ss.234-235

Özet

The present study looks into aerosols collected by a land-based, seven-wavelength Aethalometer, from the lower-free troposphere close to the summit of the Pico mountain (top height: 2351 m; sampling height: 2225 m), in Pico island, Azores, Portugal. Following suitable handling and preparation procedures, all samples were put through instrumental neutron activation analysis (INAA; k(0)-variant) for elemental assessment. Archival data have been used as an input to the HYSPLIT model (courtesy of NOAA ARL READY Website) for computing isentropic, backward trajectories of air masses reaching the Pico atmosphere. The results point to significant enrichments of molybdenum and uranium in high-altitude aerosols, especially in the summer samples. A local origin for either element is most unlikely though: Pico is a rural island, and there are no comparable records from low-altitude stations in the Azores at large. On the contrary, long-range transport from remote sources in continental areas-Europe and North-Central America-is rather compatible with the synoptic, elemental pathways converging over the Pico observatory for the period under study.