Analysis of ^7Be and ^(210)Pb air concentrations in Ny-Alesund, Svalbard: CHIMERPOL II project, preliminary results
Résumé
Half-daily high volume aerosol particles samples have been collected onto cellulose and glass fiber filters at Ny-Alesund, Svalbard, from April 14th to May 7th 2004, in the framework of CHIMERPOL II program. The filters have been analyzed for ^(210)Pb (22.3y) and ^7Be (53 d) by semiconductor gamma spectrometry. The median concentration values were 70μBq m^(-3) STP (8-264μBq m^(-3)STP) for ^(210)Pb, and 404μBq m^(-3)STP (35-824μBq m^(-3)STP) for ^7Be respectively. The ^7Be and ^(210)Pb activity concentrations measured are relatively "low" compared to those measured in Svalbard and in other Arctic sites for the same period time (April-May) during previous studies. The ^(210)Pb atmospheric concentration and atmospheric pressure are positively correlated, which may indicate that the ^(210)Pb atmospheric concentration increase as a function of air mass exchange over the Svalbard region. The results of ^7Be and ozone concentrations show also the absence of direct ^7Be stratospheric injections during our sampling campaign, in the low troposheric air masses. The performed backward trajectory analysis showed that collected aerosols and associated radionuclides concentrations were associated to three different air masses, originating from Atlantic ocean, Artic ocean and Barents Sea, and continental areas (North Finland-Russia) respectively.