Chiaki Toyama

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The metabolism of bromine in marine brown algae remains poorly understood. This contrasts with the recent finding that the accumulation of iodide in the brown alga Laminaria serves the provision of an inorganic antioxidant - the first case documented from a living system. The aim of this study was to use an interdisciplinary array of techniques to study the(More)
Atmospheric (129)I deposition was studied in different locations of Japan (Akita, Tsukuba, Tokyo, and Ishigaki Island) with samples collected between 1963 and 2005 in order to understand the distribution and sources of this nuclide and provide a reference deposition level prior to the Fukushima accident. Over this time period, the deposition pattern of(More)
Iodine-131 is one of the most critical radionuclides to be monitored after release from reactor accidents due to the tendency for this nuclide to accumulate in the human thyroid gland. However, there are not enough data related to the reactor accident in Fukushima, Japan to provide regional information on the deposition of this short-lived nuclide(More)
Atmospheric fallout samples collected from Tokyo between 1963 and 2003 were analyzed using accelerator mass spectrometry (AMS) in order to determine (129)I/(127)I ratios and to examine the deposition rate of (129)I and its secular variation in Tokyo. The (129)I/(127)I ratios in the atmosphere during 1963-1977 ranged from 1 × 10(-8) to 2 × 10(-8). This is(More)
A method was developed for the determination of (129)I in soil samples that uses an ICP-MS equipped with an octopole reaction system. Oxygen was used as the reaction gas for reducing the background intensity of m/z 129, principally by (129)Xe(+). The contribution of polyatomic ions, such as (127)IH(2)(+), could be effectively corrected for by assuming a(More)
The Kamchatka Peninsula is a prominent and wide volcanic arc located near the northern edge of the Pacific Plate. It has highly active volcanic chains and groups, and characteristic lavas that include adakitic rocks. In the north of the peninsula adjacent to the triple junction, some additional processes such as hot asthenospheric injection around the slab(More)
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