title: Leaching characteristics of EDTA-enhanced phytoextraction of Cd and Pb by Zea mays L. in different particle-size fractions of soil aggregates exposed to artificial rain.
abstract: Chelator-assisted phytoextraction is an alternative and effective technique for the remediation of heavy metal-contaminated soils, but the potential for heavy metal leaching needs to be assessed. In the present study, a soil column cultivation-leaching experiment was conducted to investigate the Cd and Pb leaching characteristics during assisted phytoextraction of metal-contaminated soils containing different particle-size soil aggregates. The columns were planted with Zea mays "Zhengdan 958" seedlings and treated with combined applications of EDTA and simulated rainfall (pH 4.5 or 6.5). The results were as follows: (1) The greatest uptake of Cd and Pb by Z. mays was observed after treatment with EDTA (2.5 mmol kg-1soil) and soil aggregates of <1 mm; uptake decreased as the soil aggregate size increased. (2) Simulated rainfall, especially acid rain (pH 4.5), after EDTA applications led to the increasing metal concentrations in the leachate, and EDTA significantly increased the concentrations of both Cd and Pb in the leachate, especially with soil aggregates of <1 mm; metal leachate concentrations decreased as soil particle sizes increased. (3) Concentrations of Cd and Pb decreased with each continuing leachate collection, and data were fit to linear regression models with coefficients of determination (R2) above 0.90 and 0.87 for Cd and Pb, respectively. The highest total amounts of Cd (22.12%) and Pb (19.29%) were observed in the leachate of soils treated with EDTA and artificial acid rain (pH 4.5) with soil aggregates of <1 mm. The application of EDTA during phytoextraction method increased the leaching risk in the following order: EDTA2.5-1(pH 4.5) > EDTA2.5-1(pH 6.5) > EDTA2.5-2(pH 4.5) > EDTA2.5-4(pH 4.5) > EDTA2.5-2(pH 6.5) > EDTA2.5-4(pH 6.5).
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: Yayin
authors: Y
authors: Lu
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China. ldggq@gzhu.edu.cn.|Key Laboratory of Water Quality Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China. ldggq@gzhu.edu.cn.
authors: Dinggui
authors: D
authors: Luo
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: An
authors: A
authors: Lai
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: Guowei
authors: G
authors: Liu
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: Lirong
authors: L
authors: Liu
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.|Key Laboratory of Water Quality Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: Jianyou
authors: J
authors: Long
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.|Key Laboratory of Water Quality Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: Hongguo
authors: H
authors: Zhang
authors: School of Environmental Science and Engineering, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.|Key Laboratory of Water Quality Safety and Protection in Pearl River Delta, Ministry of Education, Guangzhou University, No. 230, West Waihuan Road, Higher Education Mega Center, Guangzhou, Guangdong, 510006, China.
authors: Yongheng
authors: Y
authors: Chen
mesh_terms: D015258:Acid Rain; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000302:isolation & purification*; D002614:Chelating Agents; D004492:Edetic Acid / Q000737:chemistry*; D007854:Lead / Q000302:isolation & purification*; D010316:Particle Size; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis; D003313:Zea mays / Q000378:metabolism*
chemical_list: D015258:Acid Rain; D002614:Chelating Agents; D012987:Soil; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D004492:Edetic Acid
keywords: Cd- and Pb-contaminated soil; EDTA-enhanced; Heavy metal leaching risk; Phytoextraction; Soil aggregates; Zea mays L.