Leaching variations of heavy metals in chelator-assisted phytoextraction by Zea mays L. exposed to acid rainfall

• Published in: Environmental science and pollution research international Vol. 24; no. 31; pp. 24409 - 24418
• Main Authors: Lu, Yayin, Luo, Dinggui, Liu, Lirong, Tan, Zicong, Lai, An, Liu, Guowei, Li, Junhui, Long, Jianyou, Huang, Xuexia, Chen, Yongheng
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2017; Springer Nature B.V
• Subjects: Acid Rain; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biodegradation, Environmental; Cadmium; Chelating agents; Chelating Agents - analysis; Earth and Environmental Science; Ecotoxicology; Edetic acid; Edetic Acid - analysis; Environment; Environmental Chemistry; Environmental Health; Environmental Restoration and Remediation - methods; Environmental science; Ethylenediamines - analysis; Ethylenediaminetetraacetic acids; Glycolipids - analysis; Heavy metals; Leaching; Lead; Metals, Heavy - analysis; Metals, Heavy - metabolism; pH effects; Rain; Rain water; Rainfall; Regression analysis; Regression models; Research Article; Seedlings; Seedlings - drug effects; Seedlings - metabolism; Soil columns; Soil pH; Soil Pollutants - metabolism; Soil pollution; Soil remediation; Succinates - analysis; Waste Water Technology; Water Management; Water Pollution Control; Zea mays; Zea mays - drug effects; Zea mays - metabolism; Rhamnolipid; L; EDTA; EDDS; Leaching variation; Phytoextraction method; Zea mays L
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-017-0065-4

Chelant-enhanced phytoextraction method has been put forward as an effective soil remediation method, whereas the heavy metal leaching could not be ignored. In this study, a cropping-leaching experiment, using soil columns, was applied to study the metal leaching variations during assisted phytoextraction of Cd- and Pb-polluted soils, using seedlings of Zea mays , applying three different chelators (EDTA, EDDS, and rhamnolipid), and artificial rainfall (acid rainfall or normal rainfall). It showed that artificial rainfall, especially artificial acid rain, after chelator application led to the increase of heavy metals in the leaching solution. EDTA increased both Cd and Pb concentrations in the leaching solution, obviously, whereas EDDS and rhamnolipid increased Cd concentration but not Pb. The amount of Cd and Pb decreased as the leaching solution increased, the patterns as well matched LRMs (linear regression models), with R -square ( R 2 ) higher than 90 and 82% for Cd and Pb, respectively. The maximum cumulative Cd and Pb in the leaching solutions were 18.44 and 16.68%, respectively, which was amended by EDTA and acid rainwater (pH 4.5), and followed by EDDS (pH 4.5), EDDS (pH 6.5), rhamnolipid (0.5 g kg −1 soil, pH 4.5), and rhamnolipid (pH 6.5).