Publication Date: 2017.
Characterization of atmospheric aerosols collected in Monaco (2004–2008) and in sediment traps at 200 m and 1000 m water depths at the DYFAMED (Dynamics of Atmospheric Fluxes in the Mediterranean Sea) station (2004) was carried out to improve our understanding of the impact of Saharan dust on ground-level air and on the water column. Activity concentrations of natural (210Pb, 210Po, uranium and radium isotopes) and anthropogenic (137Cs, 239Pu, 240Pu, and 239+240Pu) radionuclides and their isotopic ratios confirmed a Saharan impact on the investigated samples. In association with a large particulate matter deposition event in Monaco on 20 February 2004, the 137Cs (∼40 Bq kg−1) and 239+240Pu (∼1 Bq kg−1) activities were almost a factor of two higher than other Saharan deposition dust events. This single-day particle flux represented 72% of the annual atmospheric deposition in Monaco. The annual deposition of Saharan dust on the sea was 232–407 mBq m−2 for 137Cs and 6.8–9.8 mBq m−2 for 239+240Pu and contributed significantly (28–37% for 137Cs and 34–45% for 239+240Pu) to the total annual atmospheric input to the northwest Mediterranean Sea. The 137Cs/239+240Pu activity ratios in dust samples collected during different Saharan dust events confirmed their global fallout origin or mixing with local re-suspended soil particles. In the sediment trap samples the 137Cs activity varied by a factor of two, while the 239+240Pu activity was constant, confirming the different behaviors of Cs (dissolved) and Pu (particle reactive) in the water column. The 137Cs and 239+240Pu activities of sinking particles during the period of the highest mass flux collected in 20 February 2004 at the 200 m and 1000 m water depths represented about 10% and 15%, respectively, of annual deposition from Saharan dust events.
Author affiliation: Pham, Mai Khanh. IAEA-Environment Laboratories; Mónaco
Author affiliation: Chamizo, Elena. Universidad de Sevilla; España
Author affiliation: Mas Balbuena, José Luis. Universidad de Sevilla; España
Author affiliation: Miquel, Juan Carlos. IAEA-Environment Laboratories; Mónaco
Author affiliation: Martín de Nascimento, Jacobo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina
Author affiliation: Osvath, Iolanda. IAEA-Environment Laboratories; Mónaco
Author affiliation: Povinec, Pavel P.. Comenius University; Eslovaquia
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas