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2005 Fiscal Year Final Research Report Summary

Study on the disposal of high-background heavy metal rich soils and rocks by maintaining an anoxic condition

Research Project

Project/Area Number 16560708
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Earth system and resources enginnering
Research InstitutionHOKKAIDO UNIVERSITY

Principal Investigator

IGARASHI Toshifumi  Hokkaido Univ., Graduate School of Eng., Asso.Prof., 大学院・工学研究科, 助教授 (90301944)

Co-Investigator(Kenkyū-buntansha) ASAKURA Kuniomi  Hokkaido Univ., Graduate School of Eng., Prof., 大学院・工学研究科, 教授 (20002305)
Project Period (FY) 2004 – 2005
KeywordsRock / Oxidation / reduction / Leaching / Arsenic / Oxygen concentration / pH / in situ experiments / Impoundment
Research Abstract

Leaching of acid water or heavy metal from excavated soils and rocks with high heavy metal contents is highly concerned in relation to soil and groundwater pollution after the execution of Soil Contamination Countermeasures Act in Japan. This is because the act only covers artificial pollutions, and not covers natural pollutions from high-background soils and rock of heavy metals. Therefore, the rationalization of impoundment of heavy-metal rich soils and rocks is required.
Batch leaching and column leaching experiments for pyrite-bearing rocks were carried out to clarify the mechanism of acid effluent. The results showed that the acid water occurred due to the oxidation of pyrite in the rocks, and that calcite-bearing rocks played an important role in buffering the pH of the effluent. This indicates that the use of calcite-bearing rocks is effective for mitigating the acidity of the effluent. The duplicate-impoundment method consisting of a upper pyrite-bearing layer and a bottom calcite-bearing layer is proposed.
Batch leaching experiments and in-situ impoundment experiments were conducted to clarify the mechanism of arsenic leaching. Arsenic is one of the critical elements that easily leach from excavated soils and rocks. The results showed that arsenic leaching and pyrite oxidation occurred at the same time, indicating that the arsenic is leached from pyrite during its oxidation. This suggests that the geochemical conditions, such as an oxidation/reduction potential of the impoundment control the leaching behavior. A reasonable impoundment method of arsenic-rich rocks for keeping the condition anoxic is proposed based on the experiments.

  • Research Products

    (6 results)

All 2005 Other

All Journal Article (6 results)

  • [Journal Article] カラム溶出試験による緩衝鉱物の酸性水中和現象の解明2005

    • Author(s)
      五十嵐敏文, 斉藤綾佑, 長澤俊輔, 朝倉國臣, 木村裕俊
    • Journal Title

      応用地質 46・5

      Pages: 256-264

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] 黄鉄鉱含有岩盤掘削ずりの合理的埋立法の検討-黄鉄鉱含有岩石と方解石含有岩石から構成されるカラム溶出試験-2005

    • Author(s)
      長澤俊輔, 五十嵐敏文, 朝倉國臣, 木村裕俊
    • Journal Title

      環境工学論文集 42

      Pages: 231-236

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Neutralization of acid water using pH-buffering minerals by column leaching experiments2005

    • Author(s)
      Igarashi, T., Sito, R., Nagasawa, S., Asakura, K., Kimura, H.
    • Journal Title

      Journal of Japan Society of Engineering Geology 46-5

      Pages: 256-264

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Rationalization of the impoundment of pyrite-bearing muck : Column experiments on dissolution of minerals from rock containing pyrite and calcite2005

    • Author(s)
      Nagasawa, S., Igarashi, T., Asakura, K., Kimura, H.
    • Journal Title

      Environmental Engineering Research 42

      Pages: 231-236

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Impoundment of excavated pyrite-bearing rock using silty covering soil

    • Author(s)
      Igarashi, T., Saito, R., Sarashina, M., Asakura, K.
    • Journal Title

      Clay Science (in press)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Impoundment of excavated pyrite-bearing rock using silty covering soil

    • Author(s)
      Igarashi, T., Saito, R., Sarashina, M., Asakura, K.
    • Journal Title

      Clay Science (in press)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2007-12-13  

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