A Method for Continuous (239)Pu Determinations in Arctic and Antarctic Ice Cores

Area of Science:

• Environmental Science
• Radiochemistry
• Paleoclimatology

Background:

• Atmospheric nuclear weapons testing (NWT) led to global plutonium (Pu) deposition.
• Previous methods for Pu analysis in ice cores were time-consuming and had lower resolution.
• Understanding past NWT fallout is crucial for environmental monitoring.

Purpose of the Study:

• To develop and validate a new method for continuous semiquantitative measurement of plutonium-239 (Pu) in ice cores.
• To establish annual records of NWT fallout in Greenland and Antarctic ice cores.
• To demonstrate the advantages of the new continuous measurement technique.

Main Methods:

• Direct measurement of plutonium-239 (Pu) using inductively coupled plasma-sector field mass spectrometry.
• Continuous analysis of ice cores from Greenland and Antarctica.
• Validation by comparing results with published Pu records and NWT data.

Main Results:

• Annual records of plutonium-239 (Pu) fallout from NWT were successfully developed for ten ice cores.
• Arctic Pu profiles reflected global NWT trends and agreed with lower latitude ice core data.
• Antarctic Pu measurements correlated with low latitude NWT, consistent with prior Antarctic studies.

Conclusions:

• The new continuous Pu measurement method significantly reduces analysis time and sample requirements.
• This method allows for precise coregistration of Pu data with other ice core analyses.
• The stable Pu-239 record provides a valuable, long-term archive of NWT fallout.