Improving tritium exposure reconstructions using accelerator mass spectrometry

Abstract

Direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples and permits greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Because existing methodologies for quantifying tritium have some significant limitations, the development of tritium AMS has allowed improvements in reconstructing tritium exposure concentrations from environmental measurements and provides an important additional tool in assessing the temporal and spatial distribution of chronic exposure. Tritium exposure reconstructions using AMS were previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases. Although the current quantification limit of tritium AMS is not adequate to determine natural environmental variations in tritium concentrations, it is expected to be sufficient for studies assessing possible health effects from chronic environmental tritium exposure.

Impact of the Fukushima Accident on 3H and 14C Environmental Levels: A Review of Ten Years of Investigation

“…Although it is possible to use AMS for the determination of 3 H-labelled molecules [ 54 ], the tritium concentrations of typical environmental samples are by about a factor of 100 below its limit of detection. In the case of radiocarbon, the high sensitivity of AMS enables measuring it down to the level of 14 C/ 12 C ≈ 10 −16 [ 55 ], which is sufficient for most types of environmental samples.…”

Atomic spectrometry update. Atomic mass spectrometry

“…The development of 3 H AMS improved the reconstruction of 3 H exposure concentrations from environmental measurements. 100 Although the current quantification limit was inadequate for determining natural environmental variations in 3 H concentrations, it was expected to be sufficient for studies assessing possible health effects of chronic environmental exposure to 3 H.…”