Heavy metal stabilization in contaminated soil by treatment with calcined cockle shell

• Published in: Environmental science and pollution research international Vol. 24; no. 8; pp. 7177 - 7183
• Main Authors: Islam, Mohammad Nazrul, Taki, Golam, Nguyen, Xuan Phuc, Jo, Young-Tae, Kim, Jun, Park, Jeong-Hun
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2017; Springer Nature B.V
• Subjects: Abandoned mines; Animal Shells - chemistry; Animals; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biodegradation, Environmental; Cadmium; Cardiidae; Drying; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Freezing; Heavy metals; Immobilization; Leaching; Lead; Lime; Liming; Metals; Metals, Heavy - analysis; Metals, Heavy - chemistry; Metals, Heavy - isolation & purification; Mine tailings; Mine wastes; pH effects; Powder; Research Article; Roasting; Soil amendment; Soil chemistry; Soil contamination; Soil lime; Soil pH; Soil Pollutants - analysis; Soil Pollutants - chemistry; Soil Pollutants - isolation & purification; Soil pollution; Soil stabilization; Soil treatment; Thawing; Waste materials; Waste Water Technology; Water Management; Water Pollution Control; Weathering; CaO; Immobilization; Soil pH; Contaminated soil; Heavy metals; Calcined cockle shell (CCS)
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-016-8330-5

In several previous studies, the efficacy of various liming waste materials on the immobilization of heavy metals has been tested and it was found that soils contaminated with heavy metals can be stabilized using this technique. Since lime (CaO) has been identified as the main phase of calcined cockle shell (CCS), it was hypothesized that CCS could be used as a soil amendment to immobilize heavy metals in soil. However, to date, no studies have been conducted using CCS. In this study, the effectiveness of CCS powder on the immobilization of Cd, Pb, and Zn in mine tailing soil was evaluated. After 28 days of incubation, the treated soil samples were exposed to weathering (four cycles of freezing–thawing and four cycles of wetting–drying) for 8 days before being subjected to a leaching test. The results of this study revealed that the soil pH increased from 7.5 to 12.2 with the addition of 5% CCS. A similar soil pH was obtained when the soil was amended with 5% pure CaO. By leaching with 0.1 M HCl, extracted Cd, Pb, and Zn were reduced by up to 85, 85, and 91%, respectively. Therefore, CCS is suggested as a low-cost lime-based soil amendment for stabilizing heavy metals in abandoned mining sites.