Measurement of technetium-99 in Marshall Islands soil samples by ICP-MS

Extraction techniques for recovery of technetium-99 (Tc-99) for Inductively Coupled Plasma Mass Spectrometry (ICP-MS) measurements were evaluated usin g soil samples collected from the Marshall Islands. The results of three di fferent extraction techniques were compared: (M1) acid leaching of Tc from ashed soil; (M2) acid leaching of Tc From raw dry soil; and (M3) Tc volatil ization from ashed soil using a combustion apparatus. Total Tc recoveries v aried considerably between the extraction techniques but each method yielde d similar analytical results for 99Tc, Applications of these extraction tec hniques to a series of environmental samples and ICP-MS measurements have y ielded first data on the Te-99 content of Marshall Islands soil samples con taminated with close-in radioactive fallout from nuclear weapons testing. T he Tc-99 activity concentration in the soil samples ranged between 0.1 and 1.1 mBq g(-1) dry weight (dw). The limit of detection for Tc-99 by ICP-MS w as 0.17 mBq per sample or 0.014 mBq g(-1) dw under standard operating condi tions. (C) 2000 Elsevier Science Ltd. All rights reserved.