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Katahira, Kenshi*; Moriwaki, Hiroshi*; Ishitake, Miho*; Kokubu, Yoko; Yamazaki, Hideo*; Yoshikawa, Shusaku*
Soil and Sediment Contamination, 22(8), p.1003 - 1012, 2013/07
Times Cited Count：1 Percentile：3.04(Environmental Sciences)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.
Takasaka, Yuiko*; Katahira, Kenshi*; Moriwaki, Hiroshi*; Yamazaki, Hideo*; Kokubu, Yoko; Yoshikawa, Shusaku*
no journal, ,
Metal concentrations and lead isotope ratios in a bottom sediment core from Nagasaki-bay in Japan were measured by ICP-MS following the microwave extraction method. Before 1920s, metal concentrations in the sediment core samples were low and lead isotope ratios were near those of Japanese lead ore. From the middle of the 1930s, environmental pollution by heavy metals would become visible around Nagasaki-bay because the metal concentrations in the sediments increased and lead isotope ratios were changing. Spiked peaks for several metals in the sediment core samples were observed around 1960 when industry was developed rapidly. The amount of heavy metals released to the environment would have decreased by the law for the environmental pollution enforced in 1976. In this way, metal concentrations and lead isotope ratios in sediment core reflected the activations of industry and could reveal environmental changes for 100 years around Nagasaki-bay.
