日本地球惑星科学連合2015年大会

講演情報

インターナショナルセッション(ポスター発表)

セッション記号 A (大気水圏科学) » A-GE 地質環境・土壌環境

[A-GE04] Subsurface Mass Transport and Environmental Assessment

2015年5月24日(日) 18:15 〜 19:30 コンベンションホール (2F)

コンビーナ:*森 也寸志(岡山大学大学院環境生命科学研究科)、斎藤 広隆(東京農工大学大学院農学研究院)、川本 健(埼玉大学大学院理工学研究科)、濱本 昌一郎(東京大学大学院農学生命科学研究科)、張 銘(産業技術総合研究所地圏資源環境研究部門)

18:15 〜 19:30

[AGE04-P02] 自然由来汚染土壌における鉛の長期的溶出特性評価

*張 銘1吉川 美穂1原 淳子1杉田 創1 (1.産総研)

キーワード:自然由来, 重金属類, 鉛, 長期溶出特性, 逐次溶出試験

Recent amendment of the Soil Contamination Countermeasures Act in Japan requires countermeasures to the soils including naturally occurring heavy metals, i.e., the soils even if they are naturally contaminated. Among a variety of toxic heavy metals, Lead remains a top priority for study, because it is one of the most common contaminants not only in Japan, but worldwide.

To characterize the long-term leaching properties of lead from naturally contaminated soils, six samples taken from the surroundings of different, abandoned metal mines were collected and tested. Chemical compositions, mineral compositions, cation exchange capacity, total organic carbon, total and leaching concentrations, existing form and sequential leaching concentrations of lead were systematically analyzed and examined.

The results of this study demonstrated that 1) X-ray fluorescence analysis cannot obtain comparative value of total concentration of lead for naturally contaminated soils compared with the standard test method based on acid extraction. 2) Leaching concentration does not depend on total concentration. Soil samples containing low total concentrations that are below environmental standard may have high leaching concentrations. 3) Leaching concentration is not stable during sequential and/or long-term leaching. Leaching concentration that meets environmental standard at a time may fail to meet environmental standard someday even under similar pH conditions. 4) Leaching properties of lead from naturally contaminated soils are fundamentally controlled by its existing form. 5) Compared with removing toxic heavy metals, immobilization and/or solidification together with risk-based management of naturally contaminated soils could be more cost-effective and practical.