Assessment of hexachlorcyclohexane biodegradation in contaminated soil by compound-specific stable isotope analysis. (November 2019)

• Record Type: Journal Article
• Authors: Qian, Yiguang; Chen, Ke; Liu, Yaqing; Li, Juying
• Is Part Of: Environmental pollution. Volume 254(2019)Part A
• Publication Date: 2019-11
• Subjects: Carbon isotope fractionation -- Persistent organic pollutants (POPs) -- Bioremediation of contaminated soil -- Biodegradation -- Biostimulation; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.113008
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Compound-specific isotope analysis (CSIA) was firstly applied to explore the biodegradation of hexachlorcyclohexane (HCH) isomers in contaminated soil. Concentrations and compound-specific carbon isotope ratio profiles of HCH in different specific ex-situ pilot-scale contaminated soil mesocosms were determined. The addition of nutrients and Sphingobium spp. significantly enhanced the degradation of HCH in contaminated soils within 90 days. Isomer specific biodegradation of HCHs was observed with α- and γ-HCH being more degradable than β and δ-HCH. Stable carbon isotope fractionation of HCH was observed and the δ 13 C values shifted from −28.8 ± 0.3‰ to −24.8 ± 0.7‰ upon 87.3% removal, −27.9 ± 0.2‰ to −25.9 ± 0.5‰ upon 72.8% removal, −29.4 ± 0.3‰ to −19.9 ± 0.6‰ upon 95.8% removal, and −27.8 ± 0.5‰ to −23.6 ± 0.7‰ after 96.9% removal for α, β, γ, and δ-HCH, respectively. Furthermore, the enrichment factor ε for α, β, γ, and δ-HCH biodegradation in soil was obtained for the first time as −2.0‰, −1.5‰, −3.2‰, and −1.4‰, which could play a critical role in assessing in situ biodegradation of HCH isomers in field site soil. Results from ex-situ pilot-scale experiments clearly demonstrated that CSIA could be a promising tool to qualitatively and quantitatively evaluate in situ biodegradation of HCH in contaminated field site. Graphical abstract: Image 1 Highlights: CSIA was used to assess HCHs biodegradation in contaminated soil for the first time. Addition of nutrients and Sphingobium spp. facilitated the degradation of HCHs. Isomer specific biodegradation of HCHs was observed in HCHs-contaminated soils. Stable carbon isotope fractionation occurred for HCHs biodegradation in soil. Enrichment factors εc for HCHs biodegradation in soil were obtained. Abstract : CSIA could be applicable to qualitatively and quantitatively evaluate in situ biodegradation of HCH in contaminated soil.