Activity concentration of plutonium in atmospheric precipitation

Activity concentrations of plutonium isotopes (238Pu, 239+240Pu) were determined in atmospheric precipitation samples collected in Kraków from August 2005 to December 2007. The volume of 29 samples varied in the range 14–269 dm3. The method of samples collection, preparation and radiochemical analysis proper for the separation of plutonium are indicated in brief. Monthly plutonium deposition a showed seasonal variation for 239+240Pu the first maximum was observed in August 2005 and amounted to about 2.65±0.31 mBq/m2, the second one in July 2006 – 0.371±0.063 mBq/m2 and the third one in April 2007 – 0.859±0.075 mBq/m2 and for 238Pu in September 2005 – 0.090±0.038 mBq/m2, July 2006 – 0.177±0.074 mBq/m2 and the third maximum in May 2007 – 0.333±0.028 mBq/m2. Similar behaviour of activity concentration of plutonium was also observed in other parts of the earth. Anomalously high deposition of 239+240Pu (2.65±0.31 mBq/m2) was found in August 2005. The 238Pu/239+240Pu activity ratios higher than the global fallout value ~ 0.55 (in Poland) suggested participation from different sources of plutonium.