Effects of natural and calcined oyster shells on Cd and Pb immobilization in contaminated soils

Abstract

In Korea, soils adjacent to abandoned mines are commonly contaminated by heavy metals present in mine tailings. Further, the disposal of oyster shell waste by oyster farm industries has been associated with serious environmental problems. In this study, we attempted to remediate cadmium (Cd)-and lead (Pb)-contaminated soils typical of those commonly found adjacent to abandoned mines using oyster shell waste as a soil stabilizer. Natural oyster shell powder (NOSP) and calcined oyster shell powder (COSP) were applied as soil amendments to immobilize Cd and Pb. The primary components of NOSP and COSP are calcium carbonate (CaCO 3 ) and calcium oxide (CaO), respectively. X-ray diffraction, X-ray fluorescence and scanning electron microscope analyses conducted in this study revealed that the calcination of NOSP at 770°C converted the less reactive CaCO 3 to the more reactive CaO. The calcination process also decreased the sodium content in COSP, indicating that it was advantageous to use COSP as a liming material in agricultural soil. After 30 days of incubation, we found that the 0.1 N HClextractable Cd and Pb contents in soil decreased significantly as a result of an increase in the soil pH and the formation of metal hydroxides. COSP was more effective in immobilizing Cd and Pb in the contaminated soil than NOSP. Overall, the results of this study suggest that oyster shell waste can be recycled into an effective soil ameliorant.

Effects of Biochar on Soil Quality and Heavy Metal Availability in a Military Shooting Range Soil in Korea

“…2). Soil pH plays an important role in affecting the solubility and availability of heavy metals in soil (Ok et al, 2008;Ok et al, 2010). A negative correlation was observed between TCLP-Pb and soil pH (p<0.001) ( Table 3), suggesting that pH controls the availability of Pb in the BC-amended shooting range soil.…”

Effect of Phosphate Application on Cadmium Extractability and its Uptake by Rice Cultivated in Contaminated Paddy Soil

“…(Fig. 1 (B), (C) 1979;Alidoust et al, 2015;Bolan et al, 2003;Hong et al, 2007Hong et al, , 2008Ok et al, 2010;Lee and Hong et al, 2016) 본 연구에서 인산의 최대 시용량은 390 kg P2O5/ha로써 토양 내 시용된 인산의 농도와 공시토양의 인산 농도를 합한 전체의 인산 농도는 약 310 mg P2O5/kg을 넘지 않는 것으 로 계산된다. 따라서 토양 pH가 6.3이고 인의 농도가 310 mg P2O5/kg 이하인 토양의 Cd 부동화 기작은 Cd3(PO4)2 형태의 침전 보다는 흡착에 기인한 것으로 판단된다.…”

“…첫 번째 이유 로 최소 토양의 pH가 8.0 이상의 조건에서 CdCO3와 Cd3(PO4)2 형태로 침전이 가능하고 (Naidu et al, 1994), 두 번째 이유로는 Kim 등(2015)에 따르면 토양 내 Cd 농도가 5 mg/kg일 때, 인산의 처리를 16,000 mg P/kg까지 처리 한 다 하더라도 CdCO3와 Cd3(PO4)2에 의한 침전반응이 일어 나지 않았다고 보고하였다. 따라서 1 M NH4OAc로 침출 가 능한 Cd 함량의 감소는 Cd의 침전반응 보다는 Cd의 흡착에 의해 기인되었을 가능성이 크다 (Alidoust et al, 2015;Bolan et al, 2003;Hong et al, 2010Hong et al, , 2008Ok et al, 2010).…”

Effects of Industrial By-products on Reducing Heavy Metal Leaching in Contaminated Paddy Soil

“…(Bolan et al, 2014;Lee et al, 2011;Tsang et al, 2013). 향후, 다양한 선행연구에서 보고되어 진 부산물의 특성에 의한 금속이온의 안정화; 1) 풍부한 음 이온이 복합체를 형성하여 안정화 (Hong et al, 2008;Naidu et al, 1994;Ok et al, 2010), 2) 표면의 Fe, Al 및 Mn 산 화물 등에 의한 수산화물로의 침전 (Bolan et al, 2014;Mouta et al, 2008), 3) 유기성 물질의 functional group에 의한 킬 레이트 결합 (Bolan et al, 2011;Harter and Naidu, 1995 …”