DEPOSITION OF PB-210 CS-137 PU-239-238 AND AM-241 IN THE ANTARCTIC PENINSULA AREA(240 PU)

Pb-210, Cs-137, Pu-239+240, Pu-238, and Am-241 were analysed in lichen , moss, grass and soil samples, as well as in lake sediments, from the South Shetland Islands, the Antarctic, in order to evaluate the flux and deposition of these elements. Average inventories of the analysed radionuclides in 1988 were Pb-210 (excess): 280 +/- 110 Bq m-2 (n = 15 ), Cs-137: 155 +/- 95 Bq m-2 (n = 19), Pu-239+240: 4.6 +/- 2.6 Bq m-2 (n = 19), Pu-238: 0.95 +/- 0.5 Bq m-2 (n = 19) and Am-241: 1.6 +/- 1.0 Bq m-2 (n = 19). From the maximum value of unsupported Pb-210 the ann ual deposition is determined to be 18 +/- 5 Bq m-2. The ratios Pu-238/ Pu-239+240 and Am-241/Pu-239+240 of 0.21 +/- 0.04 and 0.35 +/- 0.08 re spectively agree well with expected values in this area. A significant difference in Cs-137/Pu-239+240 ratios between lichens and moss/grass /soil is observed which may be an effect of submerging and melt water altering radionuclide ratios. From one of three lakes studied it is po ssible to perform Pb-210 dating with reasonably accuracy showing an av erage annual sediment accumulation in this lake of about 45 g m-2.