농경지 토양에서 패화석에 의한 카드뮴의 용출성 및 부동화 기작 구명 (Determining Effect of Oyster Shell on Cadmium Extractability and Mechanism of Immobilization in Arable Soil)

서지정보

· 발행기관 : 한국환경농학회
· 수록지 정보 : 한국환경농학회지 / 33권 / 4호 / 245 ~ 253페이지
· 저자명 : 홍창오, 노용동, 김상윤, 김필주

초록

BACKGROUND: Oyster shell(OS) is alkaline with pH 9.8,porous, and has high concentration of CaCO3. It could beused as an alternative of lime fertilizer to immobilizecadmium(Cd) in heavy metal contaminated arable soil.
Therefore, this study has been conducted to compare effectsof calcium(Ca) materials [OS and Ca(OH)2] on Cdextractability in contaminated soil and determinedmechanisms of Cd immobilization with OS.
METHODS AND RESULTS: Both Ca materials wereadded at the rates of 0, 0.1, 0.2, 0.4, and 0.8% (wt Ca wt-1)in Cd contaminated soil and the mixtures were incubated at25℃ for 4 weeks. Both Ca materials increased pH andnegative charge of soil with increasing Ca addition anddecreased 1N NH4OAc extractable Cd concentration. 0.1 NHCl extractable Cd concentration markedly decreased withaddition of OS. 1 N NH4OAc extractable Cd concentrationwas related with pH and net negative charge of soil, but notwith 0.1 N HCl extractable Cd concentration. We assumedthat Cd immobilization with Ca(OH)2 was mainly attributedto Cd adsorption resulted from increase in pH-inducednegative charge of soil. Scanning electron microscope(SEM) images and energy dispersive spectroscopy(EDS)analyses were conducted to determine mechanism of Cdimmobilization with OS. There was no visible precipitationon surface of both Ca materials. However, Cd was detectedin innerlayer of OS by EDS analyses but not in that ofCa(OH)2.
CONCLUSION: We concluded that Cd immobilizationwith OS was different from that with Ca(OH)2. OS mightadsorbed interlayer of oyster shell or have other chemicalreactions.

영어초록

BACKGROUND: Oyster shell(OS) is alkaline with pH 9.8,porous, and has high concentration of CaCO3. It could beused as an alternative of lime fertilizer to immobilizecadmium(Cd) in heavy metal contaminated arable soil.
Therefore, this study has been conducted to compare effectsof calcium(Ca) materials [OS and Ca(OH)2] on Cdextractability in contaminated soil and determinedmechanisms of Cd immobilization with OS.
METHODS AND RESULTS: Both Ca materials wereadded at the rates of 0, 0.1, 0.2, 0.4, and 0.8% (wt Ca wt-1)in Cd contaminated soil and the mixtures were incubated at25℃ for 4 weeks. Both Ca materials increased pH andnegative charge of soil with increasing Ca addition anddecreased 1N NH4OAc extractable Cd concentration. 0.1 NHCl extractable Cd concentration markedly decreased withaddition of OS. 1 N NH4OAc extractable Cd concentrationwas related with pH and net negative charge of soil, but notwith 0.1 N HCl extractable Cd concentration. We assumedthat Cd immobilization with Ca(OH)2 was mainly attributedto Cd adsorption resulted from increase in pH-inducednegative charge of soil. Scanning electron microscope(SEM) images and energy dispersive spectroscopy(EDS)analyses were conducted to determine mechanism of Cdimmobilization with OS. There was no visible precipitationon surface of both Ca materials. However, Cd was detectedin innerlayer of OS by EDS analyses but not in that ofCa(OH)2.
CONCLUSION: We concluded that Cd immobilizationwith OS was different from that with Ca(OH)2. OS mightadsorbed interlayer of oyster shell or have other chemicalreactions.

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