Immobilization and phytotoxicity of chromium in contaminated soil remediated by CMC-stabilized nZVI

Yu WANG, Zhanqiang FANG, Yuan KANG, Po Keung Eric TSANG

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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 Fe⁰ 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. Copyright © 2014 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)230-237
JournalJournal of Hazardous Materials
Volume275
DOIs
Publication statusPublished - Jun 2014

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Carboxymethylcellulose Sodium
phytotoxicity
Chromium
Immobilization
immobilization
chromium
cellulose
Cellulose
Soil
Iron
Soils
Remediation
Toxicity
remediation
Toxicity Tests
Bioaccumulation
Detoxification
Poisons
Brassica
toxicity

Citation

Wang, Y., Fang, Z., Kang, Y., & Tsang, E. P. (2014). Immobilization and phytotoxicity of chromium in contaminated soil remediated by CMC-stabilized nZVI. Journal of Hazardous Materials, 275, 230-237.

Keywords

  • Cr(VI)-contaminated soil
  • Nanoscale zero-valent iron (nZVI)
  • Remediation
  • Ecotoxicological effects
  • Plants