Long-term stability of cadmium and lead in a soil washing residue amended with MgO-based binders using quantitative accelerated ageing

Shen, Z., Hou, D., Xu, W., Zhang, J., Jin, F. , Zhao, B., Pan, S., Peng, T. and Alessi, D. S. (2018) Long-term stability of cadmium and lead in a soil washing residue amended with MgO-based binders using quantitative accelerated ageing. Science of the Total Environment, 643, pp. 1571-1578. (doi:10.1016/j.scitotenv.2018.06.321)

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Abstract

A soil washing residue (SWR) (containing 90% clay, cadmium (Cd2+) of 132 mg/kg, lead (Pb2+) of 3410 mg/kg) was stabilized with MgO (M) and MgO + bioapatite (MB) respectively at a dosage of 5% in w/w. The stability of the metals in original and amended SWRs was assessed after immediate treatment and using a laboratory accelerated ageing method simulating 26, 52, 78 and 104 years in field conditions. The dissolved Cd2+ and Pb2+ from the SWR in Toxicity Characteristic Leaching Procedure (TCLP) leachates significantly reduced (by 96.84–99.06%) by both amendments after immediate treatment. The stabilization remained effective within simulated 26 years as the TCLP leached Cd2+ and Pb2+ kept below regulatory levels. This immobilization was mainly due to the increased non-bioavailable Cd2+ and Pb2+ from sequential extraction tests in SWR by the amendments. At simulated 52 years, the TCLP leached Cd2+ from M and MB exceeded regulatory level by 106% and 1% respectively. Large amounts of Cd2+ and Pb2+ were leached out by 36.74–48.18% regardless of the treatments at simulated 104 years. Although bioapatite can significantly aid the stabilization of metals by MgO, the stabilization effectiveness for both treatments diminished at simulated 52 years and from 52 to 104 years.

Item Type:Articles
Additional Information:This work was supported by the National Water Pollution Control and Treatment Science and Technology Major Project (No. 2018ZX07109-003) and the National Natural Science Foundation of China (Grant No. 41671316). Moreover, this study was partly funded by the Thousand Talents Program of the Chinese government and Tsinghua University. The first author would like to thank the Killam Trusts of Canada for kindly providing the Izaak Walton Killam Memorial Postdoctoral Fellowship.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Jin, Dr Fei
Authors: Shen, Z., Hou, D., Xu, W., Zhang, J., Jin, F., Zhao, B., Pan, S., Peng, T., and Alessi, D. S.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Science of the Total Environment
Publisher:Elsevier
ISSN:0048-9697
ISSN (Online):1879-1026
Published Online:04 July 2018
Copyright Holders:Copyright © 2018 Elsevier B.V.
First Published:First published in Science of the Total Environment 643: 1571-1578
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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