Development and validation of a congener‐specific photodegradation model for polybrominated diphenyl ethers

Development and validation of a congener‐specific photodegradation model for polybrominated... With the phaseout of the manufacture of some polybrominated diphenyl ether (PBDE) formulations, namely penta‐brominated diphenyl ether (BDE) and octa‐BDE, and the continued use of the deca‐BDE formulation, it is important to be able to predict the photodegradation of the more highly brominated congeners. A model was developed and validated to predict the products and their relative concentrations from the photodegradation of PBDEs. The enthalpies of formation of the 209 PBDE congeners were calculated, and the relative reaction rate constants were obtained. The predicted reaction rate constants for PBDEs show linear correlation with previous experimental results. Because of their large volume use, their presence in the environment, and/or importance in the photodegradation of the deca‐BDE formulation, BDE‐209, BDE‐184, BDE‐100, and BDE‐99 were chosen for further ultraviolet photodegradation experiments in isooctane. The photodegradation model successfully predicted the products of the photochemical reactions of PBDEs in experimental studies. A gas chromatography retention time model for PBDEs was developed using a multiple linear regression analysis and, together with the photodegradation model and additional PBDE standards, provided a way to identify unknown products from PBDE photodegradation experiments. Based on the results of the photodegradation experiments, as well as the model predictions, it appears that the photodegradation of PBDEs is a first‐order reaction and, further, that the rate‐determining step is the stepwise loss of bromine. Our results suggest that, based on photodegradation, over time, BDE‐99 will remain the most abundant penta‐BDE, while BDE‐49 and BDE‐66 will increase greatly and will be comparable in abundance to BDE‐47. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Environmental Toxicology & Chemistry Wiley

Development and validation of a congener‐specific photodegradation model for polybrominated diphenyl ethers

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Publisher
Wiley Subscription Services, Inc., A Wiley Company
Copyright
Copyright © 2008 SETAC
ISSN
0730-7268
eISSN
1552-8618
D.O.I.
10.1897/07-570.1
Publisher site
See Article on Publisher Site

Abstract

With the phaseout of the manufacture of some polybrominated diphenyl ether (PBDE) formulations, namely penta‐brominated diphenyl ether (BDE) and octa‐BDE, and the continued use of the deca‐BDE formulation, it is important to be able to predict the photodegradation of the more highly brominated congeners. A model was developed and validated to predict the products and their relative concentrations from the photodegradation of PBDEs. The enthalpies of formation of the 209 PBDE congeners were calculated, and the relative reaction rate constants were obtained. The predicted reaction rate constants for PBDEs show linear correlation with previous experimental results. Because of their large volume use, their presence in the environment, and/or importance in the photodegradation of the deca‐BDE formulation, BDE‐209, BDE‐184, BDE‐100, and BDE‐99 were chosen for further ultraviolet photodegradation experiments in isooctane. The photodegradation model successfully predicted the products of the photochemical reactions of PBDEs in experimental studies. A gas chromatography retention time model for PBDEs was developed using a multiple linear regression analysis and, together with the photodegradation model and additional PBDE standards, provided a way to identify unknown products from PBDE photodegradation experiments. Based on the results of the photodegradation experiments, as well as the model predictions, it appears that the photodegradation of PBDEs is a first‐order reaction and, further, that the rate‐determining step is the stepwise loss of bromine. Our results suggest that, based on photodegradation, over time, BDE‐99 will remain the most abundant penta‐BDE, while BDE‐49 and BDE‐66 will increase greatly and will be comparable in abundance to BDE‐47.

Journal

Environmental Toxicology & ChemistryWiley

Published: Dec 1, 2008

References

  • Polybrominated diphenyl ether flame retardants in the North American environment
    Hale, Hale; Alaee, Alaee; Manchester‐Neesvig, Manchester‐Neesvig; Stapleton, Stapleton; Ikonomou, Ikonomou

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