Evaluation of^239+240Pu,¹³⁷Cs and natural²¹⁰Pb fallout in agricultural upland fields in Rokkasho, Japan

Plutonium isotopes concentration in seawater and bottom sediment off the Pacific coast of Aomori sea area during 1991–2005

“…The land-source Pu would be readily scavenged both with inorganic particulates and with co-existing biogenic particulates produced by a large population of plankton in the study area. Ohtsuka et al (2004) reported that the 240 Pu/ 239 Pu atom ratios (0.18 AE 0.04) in agricultural fields near the sea of concern in this study were similar to that of the global fallout (0.176 AE 0.014). Zheng and Yamada (2005b) reported that the 240 Pu/ 239 Pu atom ratios (0.186 AE 0.016) in sediments collected from the Lake Obuchi, Rokkasho were also similar to that of global fallout.…”

First determination of Pu isotopes (239Pu, 240Pu and 241Pu) in radioactive particles derived from Fukushima Daiichi Nuclear Power Plant accident

“…17 reported that the 240 Pu/ 239 Pu atom ratio was approximately 0.408 ± 0.003, and higher values of 0.45–0.52 were reported for Chernobyl hot particles 18 ; such a high value resulted from the long burn-up time of the nuclear fuel. Before the FDNPP accident, the ratios in the soils ranged from 0.14 to 0.24 in Japan 19,20 and the Pu contribution mainly originated from global fallout 16 . After the FDNPP accident, the 240 Pu/ 239 Pu atom ratio in various environmental samples around the FDNPP increased compared to the values reported previously.…”

Reconstruction of uranium and plutonium isotopic signatures in sediment accumulated in the Mano Dam reservoir, Japan, before and after the Fukushima nuclear accident

“…The global fallout signatures provided in the literature were measured worldwide (Kelley et al, 1999) including various locations across Japan (Momoshima et al, 1997;Muramatsu et al, 2003;Ohtsuka et al, 2004;Zhang et al, 2010). As the range of these Pu signatures is relatively wide (Table S3), there is a need to refine the global fallout signatures for this specific sampling location in the Fukushima Prefecture.…”

“…depth in the Mano Dam sediment core. The dashed zones provide the corresponding range of values reported for the global fallout, according to the literature (Kelley et al, 1999;Momoshima et al, 1997;Muramatsu et al, 2003;Ohtsuka et al, 2004;Zhang et al, 2010). Uncertainties are extended with a coverage factor of 2.…”