Microbial degradation of the brominated flame retardant TBNPA by groundwater bacteria: laboratory and field study

Noa Balaban, Anat Bernstein, Faina Gelman, Zeev Ronen

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

In the present study, the biodegradation of the brominated flame retardant tribromoneopentylalcohol (TBNPA) by a groundwater enrichment culture was investigated using a dual carbon (13C/12C)- bromine (81Br/79Br) stable isotope analysis. An indigenous aerobic bacterial consortium was enriched from the polluted groundwater underlying an industrial site in the northern Negev Desert, Israel, where TBNPA is an abundant pollutant. Aerobic biodegradation was shown to be rapid, with complete debromination within a few days, whereas anaerobic biodegradation was not observed. Biodegradation under aerobic conditions was accompanied by a significant carbon isotope effect with an isotopic enrichment factor of ɛCbulk = −8.8‰ ± 1.5‰, without any detectable bromine isotope fractionation. It was found that molecular oxygen is necessary for biodegradation to occur, suggesting an initial oxidative step. Based on these results, it was proposed that H abstraction from the C-H bond is the first step of TBNPA biodegradation under aerobic conditions, and that the C-H bond cleavage results in the formation of unstable intermediates, which are rapidly debrominated. A preliminary isotopic analysis of TBNPA in the groundwater underlying the industrial area revealed that there are no changes in the carbon and bromine isotope ratio values downstream of the contamination source. Considering that anoxic conditions prevail in the groundwater of the contaminated site, the lack of isotope shifts in TBNPA indicates the lack of TBNPA biodegradation in the groundwater, in accordance with our findings.

Original languageEnglish
Pages (from-to)367-373
Number of pages7
JournalChemosphere
Volume156
DOIs
StatePublished - 1 Jan 2016

Keywords

  • Biodegradation
  • Brominated flame retardants
  • Bromine isotopes
  • Carbon isotopes
  • Compound-specific isotope analysis
  • Groundwater

ASJC Scopus subject areas

  • Environmental Engineering
  • Chemistry (all)
  • Environmental Chemistry
  • Pollution
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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