Deposition rates of radionuclides in Monaco in 2002 and 2003

The monthly deposition rates of natural (7Be and 210Pb) and anthropogenic (137Cs, 239+240Pu and 241Am) radionuclides in 2002 were mainly influenced by wash-out of the atmosphere. The annual deposition rates of 7Be and 210Pb were 1190 and 250 Bq m-2 year-1, respectively, comparable with annual deposition rates of 137Cs, 239+240Pu and 241Am, which were 2200, 110 and 40 mBq m-2 year-1, respectively. An important contribution to the deposition of radionuclides in 2002 was the Saharan dust event in November 2002, when 1630, 90 and 35 mBq m-2 month-1 of 137Cs, 239+240Pu and 241Am was deposited, respectively, while only 320 mBq m-2 month-1 of 7Be and 70 mBq m-2 month-1 of 210Pb was deposited. On the contrary, in 2003 the monthly deposition rates of both natural and anthropogenic radionuclides were strongly influenced by dry deposition. The annual deposition rates of 137Cs, 239+240Pu and 241Am were 740, 14 and 5.9 mBq m-2 year-1, respectively, compared to 840 Bq m-2 year-1 for 7Be and 150 Bq m-2 year-1 for 210Pb. The anthropogenic radionuclides in the Monaco atmosphere in 2002 and 2003 originated from global fallout. (author)