Nishiyama reservoir; Lead sources, inventory, and the influence of the Nagasaki atomic bomb

Katahira, Kenshi*; Moriwaki, Hiroshi*; Ishitake, Miho*; Kokubu, Yoko; Yamazaki, Hideo*; Yoshikawa, Shusaku*

Soil and Sediment Contamination, 22(8), p.1003 - 1012, 2013/07

https://doi.org/10.1080/15320383.2013.770440

The objective of this study was to reveal historical changes in environmental pollution, including the influence of the Nagasaki atomic bomb, based on heavy metal concentrations in sediment core samples. Lead isotope ratios were used to determine the sources of Pb. A sediment core was sampled from a reservoir about 3 km east of the hypocenter of the Nagasaki atomic bomb. It was reported in a previous study that this sediment core contained high activities of Pu and Cs at the 1945 layer as a result of the Nagasaki atomic bomb. Concentrations of heavy metals and the Pb isotope ratios in sediments were measured using ICP-MS. The results show a spiked peak in the Pb concentrations in the same layer as that of the Pu and Cs. It is thought that the spiked peak is due to the loading of Pb by the Nagasaki atomic bombing, and this is supported by further results showing that the Pb isotope ratios in this layer were different from those in other layers.