A method for continuous 239 Pu determinations in Arctic and Antarctic ice cores

• Published in: Environmental Science & Technology
• Main Authors: Arienzo, MM, McConnell, JR, Chellman, N, Criscitiello, AS, Curran, M, Fritzsche, D, Kipfstuhl, S, Mulvaney, R, Nolan, M, Opel, T, Sigl, M, Steffensen, JP
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Chemical Soc 2016
• Subjects: Earth Sciences; Geochemistry; Isotope Geochemistry; Antarctic; Arctic; Greenland; The Antarctic; Antarc*; Antarctica
• Online Access: https://doi.org/10.1021/acs.est.6b01108; http://www.ncbi.nlm.nih.gov/pubmed/27244483; http://ecite.utas.edu.au/114873

Atmospheric nuclear weapons testing (NWT) resulted in the injection of plutonium (Pu) into the atmosphere and subsequent global deposition. We present a new method for continuous semiquantitative measurement of 239 Pu in ice cores, which was used to develop annual records of fallout from NWT in ten ice cores from Greenland and Antarctica. The 239 Pu was measured directly using an inductively coupled plasmasector field mass spectrometer, thereby reducing analysis time and increasing depth-resolution with respect to previous methods. To validate this method, we compared our one year averaged results to published 239 Pu records and other records of NWT. The 239 Pu profiles from the Arctic ice cores reflected global trends in NWT and were in agreement with discrete Pu profiles from lower latitude ice cores. The 239 Pu measurements in the Antarctic ice cores tracked low latitude NWT, consistent with previously published discrete records from Antarctica. Advantages of the continuous 239 Pu measurement method are (1) reduced sample preparation and analysis time; (2) no requirement for additional ice samples for NWT fallout determinations; (3) measurements are exactly coregistered with all other chemical, elemental, isotopic, and gas measurements from the continuous analytical system; and (4) the long half-life means the 239 Pu record is stable through time.