First detection of fallout Cs-135 and potential applications of ratios

Analysis of cesium isotope compositions in environmental samples by thermal ionization mass spectrometry – 1. A preliminary study for source analysis of radioactive contamination in Fukushima prefecture

“…The isotopic ratios of 135 Cs/ 137 Cs in the environmental samples were also obtained by TIMS measurements (Figure 3), and these isotopic ratios were observed to range from 0.3808 to 0.3896. Because these values were also much greater than reported isotopic ratios of global fallout (∼0.5 for Chernobyl accident [8], and ∼2.7 for nuclear weapon testing [17] (Figure 4). The isotopic ratios of 135 Cs/ 137 Cs of all samples were higher than that of the calculation results of the second and third reactors.…”

Application of natural and artificial fallout radionuclides to determining sedimentation rates in New Zealand lakes

“…This is similar to the same phenomenon already known in productive oceanic layers (e.g., Mart et al 1982;Whitfield & Watson 1983). Cs profiles, and substitute for unavailable rare earth data (Lee et al 1993). …”

Preliminary evaluation of 135Cs/137Cs as a forensic tool for identifying source of radioactive contamination

“…Different sources of contamination may be distinguished by the ratio of 135 Cs/ 137 Cs, thereby improving modelling capabilities for dispersion of anthropogenic radioactivity. The isotope, 137 Cs, has also been used in collaboration with or as an alternative to 210 Pb in sediment geochronology (Edgington et al, 1991;Walling and He, 1992;Pfitzner et al, 2004) and it has been suggested that the precision and accuracy of the dating method may be improved by the use of 135 Cs/ 137 Cs as a geochronometer tracer, although implementation of this ratio would require that the initial 135 Cs/ 137 Cs ratio is known (Lee et al, 1993).…”

“…Mass spectrometric determination is also limited by the high concentrations of stable Cs in environmental samples, as an abundance sensitivity (background at 135 Cs/signal intensity of 133 Cs) of greater than 10 9 is required (Lee et al, 1993). A further limitation is interference from stable Ba ( 135 Ba and 137 Ba, having 6.6% and 11% isotopic abundance, respectively), which is present at high concentrations in environmental samples (typically w0.1% in soils ( = 2.6 x 10 6 b) 135 and sediments).…”