著者

中村 謙吾 肴倉 宏史 川辺 能成 駒井 武

出版者

公益社団法人 土木学会

雑誌

土木学会論文集G(環境) (ISSN:21856648)

巻号頁・発行日

vol.71, no.1, pp.39-48, 2015 (Released:2015-02-20)

参考文献数

24

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製鋼スラグの利用用途で,腐植物質との混合による磯焼け回復技術が注目されているが,製鋼スラグから溶出する重金属等の環境影響を検討する必要がある.本研究では純水による検討に加えて,海域利用を想定し,実海水を用いて振とう試験および浸漬式のシリアルバッチ試験を実施した.さらに,海域利用において要求される環境安全品質の考え方に基づき,海域利用への適合性について考察を行った.試験結果より,Cd,Pb,Cr,Bは,試験条件を変えた場合に,溶出濃度が港湾用途溶出量基準を超過することは確認されず,製鋼スラグ及び腐植物質の相互作用により,重金属類の溶出濃度は減少傾向を示した.また,本研究で想定した海域利用の環境安全品質を設定し,本試験結果を適用した結果,重金属類による海域汚染の原因となる可能性は低いことが示唆された.

著者

中村 謙吾 佐藤 海里 川辺 能成 桑谷 立 駒井 武

出版者

一般社団法人 資源・素材学会

雑誌

日本鑛業會誌 (ISSN:18816118)

巻号頁・発行日

vol.132, no.1, pp.22-30, 2016

被引用文献数

2

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It is important to understand the distribution mechanism of heavy metal elements in environmental systems, because the toxicities of various metals and metalloids significantly affect health risks. The heavy metals concentrations are controlled by a wide of variety environmental factors. This study aims to clarify main influence factors on the heavy metal distribution in sediment, soil, river in the Natori River, Sendai City. We firstly produced geochemical maps for heavy metal concentrations (As, Pb and Cr) of river sediment, neighboring soil (bulk component, soluble component in 1N HCl and in pure water) and river water. The heavy metals concentrations in river water increase from upper stream to down stream, whereas heavy metal concentrations in river sediments and soil vary little from upper stream to downstream. There are no anomalous distributions of heavy metals in the studied area, although many anthropogenic materials are found in sediment, soil and river water. The correspondence analysis was applied to investigate relationships of heavy-metal concentrations between sediment, soil and river water. The results indicate that the heavy metals (As, Pb Cr and Zn) in sediment, soil and river water are dominantly controlled by natural sedimentary processes, such as denudation and sedimentation. The proposed method could be further applied for other pollutants in various environment systems. From a viewpoint of risk assessment of heavy metals, it is suggested by the presence of closer relationship of heavy metals that contains the risk information of heavy metals.

著者

桑谷 立 岡本 敦 吉田 健太 中村 謙吾 土屋 範芳 駒井 武

出版者

日本地球惑星科学連合

雑誌

日本地球惑星科学連合2018年大会

巻号頁・発行日

2018-03-14

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The high-dimensional and large amounts of data sets in geosciences show very complex behavior and often have large uncertainty. It is important to extract a small number of essential parameters which can explain the phenomenon from high-dimensional data in order to understand the behavior of dynamic solid earth. Under the framework of a big scientific project entitled as “Initiative for high-dimensional data-driven science through deepening sparse modelling” supported by the MEXT in Japan ( http://sparse-modeling.jp/index_e.html ), we try to introduce data-driven approaches into geosciences. In this presentation, we will share some applications in solid-earth science and discuss future prospects.

著者

中村 謙吾 桑谷 立 駒井 武 山崎 慎一

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.134, no.2, pp.13-21, 2018-02-01 (Released:2018-02-15)

参考文献数

36

被引用文献数

4

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Understanding the geochemical characteristics of various soils is significant for revealing the mechanisms occurring under natural conditions, assessing the environmental risks and managing the land use. However these various soils have complex forming mechanisms. This study examined geochemical characteristics of surface soils using statistical analysis. Principal component analysis (PCA), a very commonly used multivariate technique that can extract hidden structures and patterns from high-dimensional data, was applied to 633 classified soil samples. Soil samples collected in the Miyagi and Ibaraki prefectures were analyzed for major elements (Si, Ti, Al, Fe, Mg, Mn, Ca, Na and K) and heavy metals (Cr, Cu, Zn, As and Pb). Major elements showed most distinctive relationships with an inverse correlation between Si and Ti, Fe and Al. Heavy metals did not exhibit clear correlations with each other. However, background concentrations could be estimated using the frequency distribution and log-normal distribution curves. The background concentration of Cr, Cu, Zn, As and Pb were 50 ~150 mg/kg, 75 ~150 mg/kg, 200 ~300 mg/kg, 25 ~50 mg/kg and 30 ~60 mg/kg, respectively. Results of PCA clarified four common factors controlling major elements and heavy metals in the soil samples. They are ‘Physicochemical formation', ‘Soil components',‘ Vegetation effect' and ‘Adsorption and desorption'. Soils are formed by leaching reactions from rain and groundwater and mixed organic matter from different vegetation types. Therefore, major elements and heavy metals in soil are affected by these processes, which are common to most soil types.

著者

中村 謙吾 米田 稔

出版者

一般社団法人 廃棄物資源循環学会

雑誌

廃棄物資源循環学会論文誌 (ISSN:18835856)

巻号頁・発行日

vol.25, pp.25-35, 2014 (Released:2014-03-28)

参考文献数

16

被引用文献数

4

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蛍石を用いた精錬工程で発生する製鋼スラグを用いて,溶媒pHおよび温度変化による製鋼スラグの溶出量の検討を行った。また,溶出試験と同条件から粒径別の溶出量を検討した。溶出試験の結果,フッ素の溶出量は溶液のpHが影響していた。また,粒径別の溶出試験より表面からの深度に対する溶出領域と比較した場合,粒径が小さいほど推定溶出量と測定溶出値の差が大きくなった。一律推定溶出量と測定溶出量を比較すると,粒径を1.625-2, 0.425-0.5mmとした場合は各元素で0.1~10倍となった。試料粒径0-0.045mmの推定溶出量は,測定溶出量と比較して小さく (1/1000~1/10,000) なることが推測された。試料粒径0-0.045mmからの溶出は,溶出試験の溶出量に寄与しないことが示唆された。また,見かけ上製鋼スラグの溶出には,表面の1~0.1%の成分が関わっていることが示唆された。