European roe deer antlers as an environmental archive for fallout 236U and 239Pu

Abstract

Anthropogenic 236U and 239Pu were measured in European roe deer antlers hunted between 1955 and 1977 which covers and extends beyond the period of intensive nuclear weapons testing (1954-1962). The antlers were hunting trophies, and hence the hunting area, the year of shooting and the approximate age of each animal is given. Uranium and plutonium are known to deposit in skeletal tissue. Since antler histology is similar to bone, both elements were expected in antlers. Furthermore, roe deer shed their antlers annually, and hence antlers may provide a time-resolved environmental archive for fallout radionuclides. The radiochemical procedure is based on a Pu separation step by anion exchange (Dowex 1×8) and a subsequent U purification by extraction chromatography using UTEVA®. The samples were measured by Accelerator Mass Spectrometry at the VERA facility (University of Vienna). In addition to the 236U and 239Pu concentrations, the 240Pu/239Pu isotopic ratios were determined with a mean value of 0.172±0.023 which is in agreement with the ratio of global fallout (~0.18). Rather high 236U/238U ratios of the order of 10-6 were observed. These measured ratios, where the 236U arises only from global fallout, have implications for the use of the 236U/238U ratio as a fingerprint for nuclear accidents or releases from nuclear facilities. Our investigations have shown the potential to use antlers as a temporally resolved archive for the uptake of actinides from the environment.