Over the past two decades the increased industrial use of brominated flame retardants, which has doubled in less than a decade, has created growing concern over the health effects resulting from the environmental accumulation of these compounds. Tetrabromobisphenol-A [TBBPA, 4,4'-isopropylidenebis(2,6-dibromophenol)] is one of the highest-volume brominated flame retardants and its increased use over the past two decades has created growing concern over the health effects resulting from the environmental accumulation. TBBPA has been detected in environmental samples from around the world and more recently it has also been detected in human breast milk and tissues. TBBPA is persistent and is only slowly degraded in the environment. We have demonstrated that TBBPA is reductively dehalogenated under anaerobic conditions to yield bisphenol A and while TBBPA is not degraded aerobically it can be biotransformed to its correspondind mono- and dimethyl derivatives.
The microbial transformations of TBBPA result in metabolites with different chemical properties than the parent compound including an increase in lipophilicity and potential for increased environmental accumulation of the TBBPA dimethyl ether. The biotransformation of TBBPA and its derivatives may prove to be important for health risk evaluation, as TBBPA induces a number of toxicological effects including cellular oxidative stress and neurotransmitter inhibition, while BPA is a suggested endocrine disruptor. The environmental and health effects of the methyl derivatives of tetrabromobisphenol A are completely unknown. When evaluating the human and environmental health effects of TBBPA it is thus crucial to also consider its different biotransformation products, i.e. bisphenol A and the mono- and dimethyl ether derivatives. The aims of our work are to determine the extent to which brominated flame retardants are biotransformed by microbes indigenous to sediments and soils and to assess the fate and ecotoxicity of brominated flame retardants in the ecosystem.
Researchers: Jessica McCormick
Publications:
George KW, Häggblom MM (2008) Microbial O-methylation of the flame retardant tetrabromobisphenol-A. Environ. Sci. Technol. 42:5555–5561.
Ravit B, Häggblom MM, Ehrenfeld JG (2005) Salt marsh rhizosphere affects microbial biotransformation of the widespread halogenated contaminant tetrabromobisphenol A (TBBPA). Soil Biol. Biochem. 37:1049-1057.
Voordeckers J, Fennell DE, Jones K, Häggblom MM (2002) Anaerobic biotransformation of tetrabromobisphenol A, tetrachlorobisphenol A, and bisphenol A in estuarine sediments. Environ. Sci. Technol. 36:696-701.
Collaborators
Lori White, Rutgers, Dept. of Biochemistry and Microbiology
http://aesop.rutgers.edu/~dbm/loriwhite.html
