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An accident and fire at the former McGuire Air Force Base and Boeing Michigan Aeronautical Research Center (BOMARC) site in New Jersey resulted in dispersion of weapons-grade plutonium in particulate form to the local environment. Soil samples collected at the BOMARC site were measured for their activities and isotopic ratios of Pu and Am isotopes by radioanalytical techniques. The activities of the Pu and Am isotopes in the BOMARC soil were markedly higher than fallout levels, and they decreased nearly exponentially with increasing particle size of the soil. The measured (241)Am activity was compared to calculated values based on decay of (241)Pu. The activity ratios of (238)Pu/(239,240)Pu, (241)Pu/(239,240)Pu, and (241)Am/(239,240)Pu observed in the BOMARC soil were much lower than those attributed to nuclear reprocessing plants and Chernobyl fallout. From the activity ratios of (241)Pu/(239,240)Pu and (241)Am/(239,240)Pu, the origin of the Pu isotopes was identified as weapons-grade and the time since production of the material was estimated. Furthermore, the atomic ratio of (240)Pu/(239)Pu in the BOMARC soil was remarkably lower than the fallout value influenced by nuclear weapons testing and the Chernobyl accident. The atomic ratio of (240)Pu/(239)Pu was very close to the value of the weapons-grade Pu detected from the Thule accident in Greenland. This work demonstrates the utility of radioanalytical measurements and decay calculations for defining characteristics of the source term and discriminating multiple processes that contribute to a source. Such an approach would also be needed to respond to a terrorist event involving an improvised nuclear device or radiological dispersal device.

The cumulative depositions of 137Cs, 9~ and fallout Pu in the volcanic ash soil of Korea were determined. The average accumulated depositions of 137Cs, 9~ and fallout Pu in the volcanic soil were much higher than those in other forest sites of Korea. From depth profiles, it was found that 137Cs, 9~ and 239.24~ in the volcanic soil are more mobile than those in other forest sites of Korea, and that the downward movement of 9~ is faster than 137Cs and 239'24~ A significant correlation was found between the concentration of 137Cs and those of 9~ and 239'24~ The activity ratios of 238pu/239'24~ and 241pu/239,24~ in soils are close to those observed in the cumulative deposit from the global fallout of nuclear weapon testings.

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