Characterization of Saharan dust collected in Monaco during 1998-2013

PHAM, M,K.; CHAMIZO, E.; MAS BALBUENA, J.L. ; MIQUEL, J.C.; MARTÍN, J.; NIES, H.

Castellaneta Marina

Conferencia; 1st International Conference on Atmospheric Dust; 2014

Associazione Italiana per lo Studio delle Argille - onlus

Saharan dust events in the Northwest Mediterranean have been identified as important pathways for particle delivery into surface seawater [1]. The atmospheric transport of particles from North Africa to Monaco was recently studied at IAEA-EL (International Atomic Energy Agency-Environment Laboratories) [2-4]. The study of radionuclides (both natural and anthropogenic) as well as the elementary composition of Saharan dust particles was carried out for better understanding the temporal behaviour of radionuclides in the atmosphere and their transport into the Northwest Mediterranean Sea. Out of nine significant events registered episodically during 1998-2013, two important Saharan dust depositions were detected at the Monaco air monitoring station of the IAEA during 23-24 November 2002 and 20 February 2004 [4], when a significant quantity of red-colour particles was collected. The influence of the 20 February 2004 deposition was further followed into the water column with the analysis of sediment trap samples collected at two depths - 200 m and 1000 m water depth- at the Dyfamed station located at 43025?N, 07052?E (time-series studied from 21 December 2003 to 9 May 2004) [5]. The characterization of those particles was done using X-ray fluorescence (Spectro X-Lab 2000), gamma spectrometry HPGe well-type detectors of 150% and 200% relative efficiency (Canberra model CW 15025-7915-30-ULB) operating in the IAEA-EL?s underground laboratory with very low background, ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) and AMS (Accelerator Mass Spectrometry) of Universidad de Sevilla, Spain. Data on the concentrations and activity ratios of natural and anthropogenic radionuclides (gamma emitters: 7Be, 40K, 210Pb and 137Cs; alpha emitters: 210Po, 239Pu, 240Pu, 239+240Pu; and Uranium isotopes) as well as major and trace elements are presented and discussed.