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| Impact of Organic Matter Removal on Phosphate-Induced Pb Stabilization in Soil |
| Received:March 26, 2015 |
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| KeyWord:lead;stabilization;soil organic matter;mono-potassium phosphate |
| Author Name | Affiliation | E-mail | | SONG Xin-lai | College of Land and Environment, Shenyang Agriculture University, Shenyang 110866, China
Chinese Research Academy of Environmental Sciences, State Key Laboratory of Environment and Risk Assessment, Beijing 100012, China | | | WANG Yao-jing | College of Land and Environment, Shenyang Agriculture University, Shenyang 110866, China | | | ZHANG Zhuo | Chinese Research Academy of Environmental Sciences, State Key Laboratory of Environment and Risk Assessment, Beijing 100012, China | | | WANG Mei | Chinese Research Academy of Environmental Sciences, State Key Laboratory of Environment and Risk Assessment, Beijing 100012, China | | | WANG Sen | Chinese Research Academy of Environmental Sciences, State Key Laboratory of Environment and Risk Assessment, Beijing 100012, China | | | GUO Guan-lin | Chinese Research Academy of Environmental Sciences, State Key Laboratory of Environment and Risk Assessment, Beijing 100012, China | guogl@craes.org.cn |
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| Abstract: |
| Phosphate-containing materials are important stabilizers of soil Pb. However, soil organic matter may impact phosphate-induced Pb stabilization in soil. In the present study, the effect of soil organic matter on the Pb stabilization by phosphate was evaluated by comparing toxicity characteristic leaching procedure(TCLP), phosphate contents, and Pb fractionation of soils that were subjected to removal and non-removal of organic matter and then spiked with seven molar ratios of P/Pb. Soil organic matter was removed by two methods, i.e. muffle furnace calcination and hydrogen peroxide oxidation. Results indicated that the removal efficiencies of soil organic matters by muffle furnace and hydrogen peroxide were 97.2% and 11.3%, which in turn caused available Pb fractions increase by 43.4% and 75.8%, respectively. At 1.2 of P/Pb molar ratio, soil available Pb content was 0.4 mg·L-1, 0.8 mg·L-1, and 0.5 mg·L-1, while available phosphorus content was 68.0 mg·kg-1, 87.0 mg·kg-1, and 70.0 mg·kg-1 for non-organic matter removal, muffle furnace treatment and hydrogen peroxide treatment, respectively. The main chemical form of Pb was residual fraction in untreated and treated soils. Organically bound Pb reduced after the removal of organic matters. Removing soil organic matters could reduce the stabilization of Pb in contaminated soils, thus increasing the bioavailability and environmental risks of soil Pb. |
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