The objectives of this study were to investigate the distribution and chemical characteristics of cations in annual rings of Japanese cedar (Cryptomeriajaponica D. Don) grown in a healthy stand of an unindustrialized region in Japan and discuss the possibility of using cations in tree-rings as a chronological index of acidic deposition. Radial distributions of some cations and P at different vertical positions of the stem were analyzed for five trees from the same mountain. Each cation and P in all trees showed a specific distribution in its radial pattern but similar distribution trends were observed at all vertical positions. The cations and P were classified into three groups: (I) constant radial concentrations (Ca 2 + , Sr 2 +, Na ÷ , and probably Ba 2 +), (II) high concentrations in the heartwood and low in the sapwood (Mg +, K + , Rb ÷ , Cs +), and (IH) increasing concentrations in sapwood (P, Mn z ÷, Cũ +). The total concentration of cations exceeded the calcium-binding capacity (CBC) of the wood, and the excess was attributed to K + in a salt form. The CBC increased from the sapwood/ heartwood boundary toward the pith in the heartwood but remained constant in the sapwood. The increase of CBC in the heartwood was consistent with the profile of Mg 2+ , indicating a transfer of Mg + into heartwood and fixation on the acquired binding site. The radial distribution of 9°Sr was closely related to the cumulative deposition of fallout from the nuclear weapon tests, but that of ~TCs was unrelated. This suggests immobility of Sr~ + and mobility of Cs ÷ in the horizontal direction of wood. The conservation of the historical ~eSr/Sr2 + change indicated that no influence of heartwood formation on the chemical environment of Sr~+ in cedar xylem and a possibility of using Sr + as a chronological index of nutrient availability. A steady-state in nutrient availability is speculated for trees growing in this mountain because all of the trees analyzed show constant radial distributions of Sr 2 + for decades.

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and mixing. While the 134 Cs and 137 Cs concentrations of highly contaminated surface seawater samples around the FDNPP have been studied extensively (Tsumune et al., 2012; Honda et al., 2012), relatively little information is available on radionuclide concentrations in seawater for other sea areas around the Japanese Archipelago. We previously reported low levels of 134 Cs and 137 Cs concentrations in surface water samples from the Pacific Ocean side of northeastern Japan, the Japan Sea, and the southwestern Okhotsk Sea before and after the FDNPP accident; however, the scope of these studies was somewhat cursory (Inoue et al., 2012a, b). Nonetheless, these studies illustrated the need for more extensive temporal and spatial investigations to assess the oceanic behaviors and fate of Fukushima-derived radionuclides around the Japanese Islands. We therefore used low-background γ-spectrometry to characterize the lateral variations of 134 Cs and 137 Cs concentrations in surface waters around the Japanese Archipelago in June and October 2011. These data were combined with 134 Cs deposition data (Ministry of Education,

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We analyzed a total of 25 seawater samples collected from 2 columns within the Sea of Japan for 226 Ra (half life 1,600 years) and 228 Ra (half life 5.75 years) by employing low-background c-spectrometry. The 228 Ra activity level in the deep proper water (DPW) (*0.13 mBq/L) was found to be higher than that of deep waters from the Pacific and Atlantic Oceans (\0.1 mBq/L), indicating its continuous delivery to the DPW by active water circulation before complete radioactive decay. Using a steady state box model of 226 Ra and 228 Ra, the turn-over time in the DPW was calculated to be *80 years.

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