著者

有馬 孝彦 佐々木 亮介 Carlito Baltazar TABELIN 田本 修一 山本 隆広 Tangviroon PAWIT 五十嵐 敏文

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.136, no.6, pp.64-76, 2020-06-30 (Released:2020-06-30)

参考文献数

21

被引用文献数

1

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Rocks generated from tunnel construction projects for roads and railways throughout Japan have often leached out hazardous trace elements, such as arsenic (As) and selenium (Se). In nature, the oxyanionic species of As and Se have a variety of chemical species, so speciation is one of the crucial factors in their migration through natural geologic media. In this study, column experiments consisting of four types of crushed rock samples containing As and Se, and a river sediment (RS) as an adsorbent obtained near the tunnel construction site were conducted to evaluate the leaching and adsorption behavior of arsenite (As (III) ), arsenate (As (V) ), selenite (Se (IV) ), and selenate (Se (VI) ). The results showed that the dominant speciation of As and Se in the effluent from the rock layer was As (V) and Se (VI), and that the addition of a bottom RS adsorption layer or the mixing of RS with the rock layer decreased the leaching concentrations of As (III), As (V), Se (IV), and Se (VI). Cumulative leachability (CL) for each speciation through the column experiments was calculated to evaluate the amounts of As and Se retained in RS. The calculated CL showed that the bottom RS layer or mixing of RS with the rock reduced the CL of As (III), As (V), Se (IV), and Se (IV) ranging from 60 to 89%, 73 to 89%, 9 to 75%, and 36 to 60%, respectively; however, mixing of RS with the rock layer was ineffective in decreasing CL of Se (VI). The reduction of CL may be due to adsorption and/or coprecipitation by iron and/or aluminum oxides contained in RS. These results indicated that utilization of RS for the bottom adsorption layer was effective in reducing As and Se concentrations irrespective of their speciation, although that of mixed with rock layer was effective only in reducing As concentrations irrespective of their speciation.

著者

山本 隆広 渡邉 聖樹 三浦 彰子 平原 智雄 平野 照之 内野 誠

出版者

日本神経学会

雑誌

臨床神経学 (ISSN:0009918X)

巻号頁・発行日

vol.50, no.10, pp.718-724, 2010 (Released:2010-11-04)

参考文献数

26

被引用文献数

4 6

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症例は51歳の男性である.2カ月前より頭痛,活動性の低下,見当識障害が徐々に進行し当科入院した.頭部MRI T2強調画像にて両側視床に高信号域をみとめ,左傍中脳に静脈の拡張と思われるflow voidをみとめた.脳血管造影にて,左上錐体静脈洞部に硬膜動静脈瘻をみとめた.流入動脈は内頸動脈が中心であり,流出静脈は深部静脈系へ逆流していた.このため両側視床の灌流障害をきたしていると考えられた.主な流入血管に対し経動脈的塞栓術を施行したところ見当識障害と視床病変の改善がえられた.硬膜動静脈瘻は両側視床病変の原因となることもあり,治療介入で改善が期待できるため,早期診断が望ましい疾患である.