Correspondence/Rebuttal pubs.acs.org/est
Comment on “Novel Methoxylated Polybrominated Diphenoxybenzene Congeners and Possible Sources in Herring Gull Eggs from the Laurentian Great Lakes of North America”
C
hen et al.1 tentatively identified unknown halogenated substances in herring gull eggs as methoxylated polybrominated diphenoxybenzene (MeO-PBDPB) congeners, and speculated the unknowns were metabolites or degradation products of an Albemarle product, SAYTEX 120 Flame Retardant. Albemarle Corporation would like to correct certain inaccuracies in the publication, and provide additional information. The authors state “SAYTEX 120 is a currently used BFR”. Albemarle discontinued manufacture of the product some time ago, with limited distribution through 2010 and January 2011. SAYTEX 120 was produced for essentially one North American customer in volumes substantially below those of major-use brominated flame retardants, and based on this alone, its environmental distribution is expected to be limited. With a molecular weight of 1366.9, 14 bromine atoms, and negligible solubility, the molecule is highly unlikely to be bioaccumulated or bioconcentrated. Thus, metabolism in gulls or other vertebrates is not expected. The molecule is stable and unlikely to undergo environmental biodegradation. The highest concentration of the six unknowns, 36.8 ng/g w.w., was detected in gull eggs collected on Channel-Shelter Island, Lake Huron. The sum of these six unknowns at the remaining sites ranged from not detected to 8.5 ng/g w.w. Although not mentioned in the publication, Channel-Shelter Island is a man-made structure designated as a confined disposal facility (CDF) by the U.S. Army Corps of Engineers.2 Channel-Shelter Island, like other CDFs in and around the Great Lakes, was created for the disposal of spoils derived from dredging navigation channels. Birds and other organisms dwelling on the island would come in contact with higher amounts of sediment-derived materials than would otherwise occur.3 Thus, exposures at those sites are likely atypical. The authors noted the vast array of naturally occurring halogenated compounds, but considered it only a remote possibility that the unknowns were derived from natural sources. Gribble4 documented some 4714 naturally occurring organohalogen compounds, while Chen et al. assert “75 different BFRs have been commercially produced”. Based on the numbers alone, a halogenated substance in the environment is more likely to be naturally occurring than anthropogenic. While more abundant in marine systems, naturally occurring organohalogens are also observed in terrestrial and freshwater environments. The freshwater Great Lakes have substantial regional sources of chlorine and bromine, with mining for salt and bromine-bearing brines dating back to the early 1900s.5,6 We note methoxy- and hydroxy-polybrominated diphenyl ethers, once believed to be solely metabolites of commercial polybrominated diphenyl ethers, are now known to occur naturally.7−11 We would also like to correct an earlier ES&T publication12 by three of the authors to the effect that 1,2-dibromo-4-(1,2© 2012 American Chemical Society
dibromoethyl)cyclohexane and 1,25,6-tetrabromocyclooctane were being marketed by Albemarle as “Saytex BCL-462” and “Saytex BCL-48”, respectively. Albemarle has discontinued manufacture of both products; BCL-462 years ago. BC-48 was distributed through 2010. Neither product was produced in substantial quantities. Their reported detection in environmental samples is unlikely given their limited use, but consistent with a presumption that organobromines in the environment are related to the manufacture and use of brominated flame retardants.
Marcia L. Hardy*,† Tyson Hall‡ Steve W. Le Van§ †
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Health, Safety and Environment, Albemarle Corporation, 451 Florida Street, Baton Rouge, Louisiana ‡ Polymer Solutions, Albemarle Corporation, 451 Florida Street, Baton Rouge, Louisiana § Advocacy, Albemarle Corporation, 451 Florida Street, Baton Rouge, Louisiana
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare the following competing financial interest(s): The authors are employed by Albemarle Corporation, a specialty chemical company whose product line includes brominated substances. The origin of a substance reported in gull eggs was attributed to a product of the corporation.
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REFERENCES
(1) Chen, D., Letcher, R. J., Gauthier, L. T., Chu, S., McCrindle, R., Potter, D. Novel methoxylated polybrominated diphenoxybenzene congeners and possible sources in herring gull eggs from the Laurentian Great Lakes of North America. Environ. Sci. Technol. 2011, 45, 9523−9530. DOI:10.1021/es201325g. (2) Great Lakes Confined Disposal Facilities. April 2003. Department of the Army−U.S. Army Corps of Engineers. U.S. Environmental Protection Agency. http://www.lrd.usace.army.mil/_kd/ Items/ actions.cfm?action=Show&item_id=1654&destination=ShowItem (accessed November 14, 2011). (3) Measures of Success: Addressing Environmental Impairments in the Saginaw River and Saginaw Bay. August 2000. Prepared by Public Sector Consultants, Inc. for The Partnership for the Saginaw Bay Watershed. http://www.pscinc.com/Portals/0/Publications/Saginaw_ Bay/2000_ Measures_Success/report.PDF (accessed November 14, 2011). (4) Gribble, G. W.. Naturally Occurring Organohalogen Compounds A Comprehensive Update, Progress in the Chemistry of Organic Natural
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Environmental Science & Technology
Correspondence/Rebuttal
Products; Springer-Verlag/Wien, 2010; Vol. 91, DOI 10.1007/978-3211-99323-1_1.. (5) Map, . Major Salt Deposits and Dry Salt Production Sites in North America. www.saltinstitute.org (accessed November 14, 2011). (6) The Mineral Industry; Dwalter Renton Ingels. Ed.; The Engineering & Mining Journal. McGraw-Hill Book Company: New York, 1909; Vol. 17. (7) Vetter, W.; Jun, W. Non-polar halogenated natural products bioaccumulated in marine samples. II. Brominated and mixed halogenated compounds. Chemosphere 2003, 52, 423−431. (8) Teuten, E.; Xu, L.; Reddy, C. Two abundant bioaccumulated halogenated compounds are natural products. Science 2005, 307, 917− 920. (9) Malmvarn, A.; Zebuhr, Y.; Katusky, L.; Bergman, A.; Asplund, L. Hydroxylated and methoxylated polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins in red algae and cyanobacteria living in the Baltic Sea. Chemosphere 2008, 72, 910−916. (10) Guitart, C.; Slattery, M.; Ankisetty, S.; Radwan, M.; Ross, S. J.; Letcher, R. J.; Reddy, C. M. Contemporary 14C radiocarbon levels of oxygenated polybrominated dipheyl ethers (O-PBDEs) isolated in sponge-cyanobaterial associations. Mar. Pollut. Bull. 2011, 62, 631− 636. (11) Unger, M.; Asplund, L.; Marsh, G.; Gustafsson, O. Characterization of an abundant and novel methyl- and methoxy-substituted brominated diphenyl ether isolated from whale blubber. Chemosphere 2010, 79, 408−413. (12) Gauthier, L. T.; Potter, D.; Hebert, C. E.; Letcher, R. J. Temporal trends and spatial distribution of non-polybrominated diphenyl ether flame retardant in the eggs of colonial populations of Great Lakes herring gulls. Environ. Sci. Technol. 2009, 43, 312−317.
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