Using Phosphorus and Zeolite to Immobilize Lead in Two Contrasting Contaminated Urban Soils
Junhui Li1,2, Chongjian Jia1, Ying Lu1, Hojae Shim3
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1College of Natural Resources and Environmental Science, South China Agricultural University,
Guangzhou 510642, China
2Department of Earth System Science, University of California, Irvine, CA 92697, USA
3Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau,
Macau SAR 999078, China
Submission date: 2015-12-27
Final revision date: 2016-02-23
Acceptance date: 2016-02-23
Publication date: 2016-07-22
Pol. J. Environ. Stud. 2016;25(4):1589–1594
Lead (Pb) contamination of urban soil is a threat to human health, and reducing the risk of Pb-contaminated soil is a continuing international concern. Soil stabilization technique has been considered as a promising remediation technique to facilitate the immobilization of Pb in soil. The purpose of this study was to evaluate the effects of different amendments, including H3PO4, Ca(H2PO4)2, H3PO4+Ca(H2PO4)2, and zeolite on Pb levels in two naturally contaminated urban soils. Pb speciation and bioavailability was evaluated by the sequential extraction test (SET) and the toxicity characteristic leaching procedure (TCLP) after a two-month incubation. The application of phosphorus amendments significantly reduced the TCLP-Pb concentration in two soil types and the SET-Pb in Soil 1 (alkaline but with high Pb level), whereas the zeolite amendment diminished the SET-Pb in two soil types and the TCLP-Pb in Soil 1. Nevertheless, regardless of the soil type, the application of phosphorus amendments resulted in a significant increase of residual Pb. These phosphate amendments may be a viable strategy in the in situ remediation of Pb contamination in urban soils.