Anaerobic degradation of hexachlorohexane during anaerobic digestion of pesticide contaminated biomass tracked by compound-specific stable isotope analysis
The legacy of hexachlorocyclohexane (HCH) isomers in industry deposits and contaminated sites has become a global issue,due to the persistent hazardous effects on human and ecosystems.In this study,we investigated the anaerobic digestion as the potential solution for energetic utilization of contaminated lands via anaerobic digestion of the pesticide contaminated biomass to produce biogas.A concept based on stable isotope fractionation for identification of degradation mechanisms of HCH isomers during anaerobic digestion was established.Experiments on batch biogas production under three different initial concentrations (5 mg/L,50 mg/L and 150 mg/L with α and γ-HCH,separately) were conducted,and an inhibition effect was observed only at 150mg/L.The carbon isotope value (δ13C) of CH4 showed a significant fluctuation after the inhibition phase (from-57.3 ±0.2‰ to-19.3±0.3‰) in 150 mg/L HCHs assay,compared with the value during the same period in controls without HCH (-46.9±0.3‰).We assumed that the toxicity of HCHs influenced the activity of methanogens and the accumulation of volatile organic acids which resulted in a variation on δ13C of CH4.Batch experiment with γ-HCH at 50 mg/L was carried out to identify the degradation pathway.Compound specific stable isotope analysis of γ-HCH was used to trace the degradation mechanisms and metabolic pathways.The carbon isotope value (δ13C) of γHCH was enriched from-30.0±0.4‰ to-27.1±0.3‰ and the carbon isotope value of benzene changed from-30.8±0.1‰ to-33.5±0.4‰.Combined with the results from detection of metabolites via GC-MS methods,it was demonstrated that γ-HCH can be degraded to chlorobenzene and benzene via anaerobic reductive dechlorination and that the anaerobic digestion appears to be a good option for the degradation of the HCH isomers present in polluted biomass.
HCHs anaerobic digestion inhibition stable isotope dechlorination
SHUJUAN LIAN MARCELL NIKOLAUSZ IVONNE NIJENHUIS ATHAYDES FRANCISCO LEITE HANS HERMANN RICHNOW
Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstra Department of Environmental Microbiology Helmholtz Centre for Environmental Research-UFZ, Permoserst
国际会议
The 15th IWA World Conference on Anaerobic Digestion( 第15届IWA世界厌氧大会)
北京
英文
99-102
2017-10-17（万方平台首次上网日期，不代表论文的发表时间）