Zhiyuan Shi , Kimikazu Sasa , Masumi Matsumura , Tsutomu Takahashi , Yuichi Takaku , Michinobu Kuwae , Shinya Yamasaki , Keisuke Sueki , Aya Sakaguchi
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引用次数: 0
Abstract
Anthropogenic 129I has been used as a powerful tool for tracing human nuclear activities. This study measured 127I concentrations and 129I/127I ratios in a sediment core from Beppu Bay, Japan, to evaluate the potential of 129I as a key marker for the Anthropocene. The 129I/127I ratios ranged from 1.16 × 10−11 to 1.11 × 10−10 and showed a clear increase in the 1950s, consistent with the beginning of global nuclear activities. This variation agrees with previously reported records from East Asia. Owing to the high sedimentation rate, well-preserved lamination, and redox conditions in Beppu Bay, the core retained both global increase of anthropogenic 129I and several distinct local short-term peaks of local origin. The timeline of these peaks are likely to coincides to local volcanic eruptions and extreme weather events that enhanced 129I/127I, and slightly elevated 129I/127I ratio in pre-nuclear layers suggest limited post-depositional migration under reducing conditions. Overall, the Beppu Bay core provides a high-resolution and well-dated record of 129I deposition influenced by both global and local signals. These results support the potential of 129I as a key marker in coastal marine environments for defining the Anthropocene.
期刊介绍:
The Journal of Environmental Radioactivity provides a coherent international forum for publication of original research or review papers on any aspect of the occurrence of radioactivity in natural systems.
Relevant subject areas range from applications of environmental radionuclides as mechanistic or timescale tracers of natural processes to assessments of the radioecological or radiological effects of ambient radioactivity. Papers deal with naturally occurring nuclides or with those created and released by man through nuclear weapons manufacture and testing, energy production, fuel-cycle technology, etc. Reports on radioactivity in the oceans, sediments, rivers, lakes, groundwaters, soils, atmosphere and all divisions of the biosphere are welcomed, but these should not simply be of a monitoring nature unless the data are particularly innovative.