title: Effect of soil washing with only chelators or combining with ferric chloride on soil heavy metal removal and phytoavailability: Field experiments.
abstract: In a field experiment on multi-metal contaminated soil, we investigated the efficiency of Cd, Pb, Zn, and Cu removal by only mixture of chelators (MC) or combining with FeCl3. After washing treatment, a co-cropping system was performed for heavy metals to be extracted by Sedum alfredii and to produce safe food from Zea mays. We analyzed the concentration of heavy metals in groundwater to evaluate the leashing risk of soil washing with FeCl3 and MC. Results showed that addition of FeCl3 was favorable to the removal of heavy metals in the topsoil. Metal leaching occurred mainly in rain season during the first co-cropping. The removal rates of Cd, Zn, Pb, and Cu in topsoil were 28%, 53%, 41%, and 21% with washing by FeCl3+MC after first harvest. The application of FeCl3 reduced the yield of S. alfredii and increased the metals concentration of Z. mays in first harvest. However, after amending soil, the metals concentration of Z. mays in FeCl3+MC treatment were similar to that only washing by MC. The grains and shoots of Z. mays were safe for use in feed production. Soil washing did not worsen groundwater contamination during the study period. But the concentration of Cd in groundwater was higher than the limit value of Standard concentrations for Groundwater IV. This study suggests that soil washing using FeCl3 and MC for the remediation of multi-metal contaminated soil is potential feasibility. However, the subsequent measure to improve the washed soil environment for planting crop is considered.
authors.affiliation: School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China; College of Natural Resources and Environment, Key Laboratory of Ecological Agriculture of Ministry of Agriculture of China, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Guo
authors.affiliation: College of Natural Resources and Environment, Key Laboratory of Ecological Agriculture of Ministry of Agriculture of China, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Zebin
authors.initials: Z
authors.lastname: Wei
authors.affiliation: College of Natural Resources and Environment, Key Laboratory of Ecological Agriculture of Ministry of Agriculture of China, South China Agricultural University, Guangzhou 510642, China. Electronic address: wuqitang@scau.edu.cn.
authors.forename: Qitang
authors.initials: Q
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing Building Materials Academy of Science Research, Beijing 100041, China.
authors.forename: Chunping
authors.initials: C
authors.lastname: Li
authors.affiliation: School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China.
authors.forename: Tianwei
authors.initials: T
authors.lastname: Qian
authors.affiliation: School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D001682:Biological Availability; D002614:Chelating Agents / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D060587:Groundwater / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D031963:Sedum / Q000378:metabolism; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000032:analysis; D003313:Zea mays / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D002712:Chlorides; D005290:Ferric Compounds; D019216:Metals, Heavy; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; C024555:ferric chloride
keywords: Co-cropping; FeCl(3); Groundwater; Heavy metals; Mixture of chelators (MC); Soil washing