title: Immobilization and phytotoxicity of chromium in contaminated soil remediated by CMC-stabilized nZVI.
abstract: The toxic effect of Cr(VI)-contaminated soil remediated by sodium carboxymethyl cellulose stabilized nanoscale zero-valent iron (CMC-stabilized nZVI) was assessed through in vitro toxicity and phytotoxicity tests. In vitro tests showed that 0.09 g L(-1) of Fe(0) nanoparticles (soil-to-solution ratio was 1 g:5 mL) significantly reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiological based extraction test (PBET) bioaccessibility of Cr by 82% and 58%, respectively. Sequential extraction procedures (SEP) revealed that exchangeable (EX) Cr was completely converted to Fe-Mn oxides (OX) and organic matter (OM). Accordingly, phytotoxicity tests indicated that after 72-h remediation, Cr uptakes by edible rape and Chinese cabbage were suppressed by 61% and 36%, respectively. Moreover, no significant increase in Cr uptake was observed for either species after a 1-month static period for the amended soil. Regarding Fe absorption, germination and seedling growth, both plant species were significantly affected by CMC-nZVI-exposed soils. However, similar phytotoxicity tests conducted after 1 month showed an improvement in cultivation for both plants. Overall, this study demonstrated that CMC-nZVI could significantly enhance Cr immobilization, which reduced its leachability, bioavailability and bioaccumulation by plants. From a detoxification perspective, such remediation is technologically feasible and shows great potential in field applications.
authors.affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong 510006, China; Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou, Guangdong 510006, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong 510006, China; Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou, Guangdong 510006, China. Electronic address: zhqfang@scnu.edu.cn.
authors.forename: Zhanqiang
authors.initials: Z
authors.lastname: Fang
authors.affiliation: School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong 510006, China; Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou, Guangdong 510006, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Kang
authors.affiliation: Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou, Guangdong 510006, China; Department of Science and Environmental Studies, Hong Kong Institute of Education, Hong Kong 00852, China.
authors.forename: Eric Pokeung
authors.initials: EP
authors.lastname: Tsang
mesh_terms: D001937:Brassica / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry* / Q000493:pharmacokinetics / Q000633:toxicity; D052918:Environmental Restoration and Remediation; D018525:Germination / Q000187:drug effects; D007501:Iron / Q000737:chemistry* / Q000493:pharmacokinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D018547:Plant Stems / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012989:Soil Pollutants / Q000737:chemistry* / Q000493:pharmacokinetics / Q000633:toxicity
chemical_list: D012989:Soil Pollutants; D002857:Chromium; D007501:Iron; D002266:Carboxymethylcellulose Sodium
keywords: Cr(VI)-contaminated soil; Ecotoxicological effects; Nanoscale zero-valent iron (nZVI); Plants; Remediation