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Comment on “Brominated Flame Retardants in Children’s Toys: Concentration, Composition, and Children’s Exposure and Risk Assessment” Chen et al. (1) reported detection of brominated flame retardants (BFRs) [i.e., polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6tribromophenoxy)ethane, and polybrominated biphenyls], in childrens’ toys purchased in China. We wish to raise several important issues about this work, as discussed below. First, the authors assumed that flame retardant additives were present in the “...plastic, rubber, textile, or stuffing material of these toys”. The levels reported by Chen et al. (1), however, are too low to have offered any flame retardancy. For example, DBDPE concentrations in the hard plastic toys ranged from nondetectable to 117,006 ng/g, with PBDE-209 having the highest concentration at 4,231,832 ng/g (1). Both of these BFRs require a minimal level of 100,000,000 ng/g to flame retard (e.g., V-0 high impact polystyrene); therefore, it is unclear why these compounds were detected in the matrices evaluated. Second, the analytical method employed by Chen et al. (1), while utilizing mass spectrometry, was not based on detection of any analyte’s molecular ion. Identification was based on ion fragments mass-to-charge ratio (m/z) 79 and 81 for the bromine atom, with the exception that m/z 486.7 and 488.7 were also recorded for PBDE-209. Thus, the reported BFRs were not definitively identified, and this may account for their apparent detection. Third, Chen et al. (1) utilized the area-specific emission rates (SERas) derived by Kemmlein et al. (2) from a 1970s era television cabinet back containing ∼7.3% octabromodiphenyl ether for estimating PBDE inhalation exposures, although constant SERas would not be expected in plastics with BFR concentrations spanning 3 orders of magnitude (2). Fourth, the input parameters used by Chen et al. (1) for BFR exposure assessment appear improbable. Inhalation rates from the U.S. Environmental Protection Agency’s (EPA’s) 1997 Exposure Factors Handbook of 4.5-14.5 m3/ min were cited whereas the correct units are in m3/day (see Table 5-23 in ref 3). The age groups in Chen et al.’s Table S1 (1) are confusing [cf. with the Table 5-23 of the Handbook (3)] and inhalation rates reported by Chen et al. (1) were composites of the Exposure Factors Handbook’s values, although the EPA’s Child-Specific Exposure Factors Handbook values are a more appropriate source (4). Additional parameters that are questionable include, but are not limited to, a total toy surface area of 2.0 m2 and a room volume of 210 cm3. Fifth, Chen et al. (1) performed studies on human subjects who mouthed pieces of toys in order to determine BFR extraction rates in saliva. Humans were tested because, according to the authors, “...no related information can be obtained in the literature...”. The authors’ affiliations are from research institutes in the U.S. and China. In the U.S., an institutional review board (IRB) must approve research on human subjects; the research must also comply with federal, state, and local regulations. Outside of the U.S., researchers typically provide documentation that human studies were performed according to the principles of the Declaration of Helsinki. However, no information is provided in Chen et al. (1) about IRB approval, written informed consent of study participants, etc. This information should have been pro1152
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vided. Alternatively, if the authors’ research on human subjects did not require IRB approval, this should have been clearly stated. Regardless, we note that information on the potential extraction of some BFRs by saliva was already available (5-7). Sixth, Chen et al. (1) concluded children can be exposed via toys to significant amounts of non-PBDE BFRs, which have “...limited” toxicological data. However, Chen et al. (1) did not estimate exposures from non-PBDE BFRs, and as reported previously with respect to DBDPE, sufficient data is available for performance of a human health risk assessment (8, 9). Finally, Chen et al. (1) noted the EPA’s “low” confidence with regard to their calculated reference dose (RfD) on PBDE209. The EPA’s RfD was calculated from a developmental neurotoxicity study, in which the authors failed to control for litter effects (10). A guideline-compliant developmental neurotoxicity study (11) performed under Good Laboratory Practice standards was unable to reproduce the affects reported in the study relied upon by the EPA, other studies which failed to control for litter effects (12-14), and a study which used a litter-based design (15). Chen et al. (1) also expressed concern over the RfD because young children may be more sensitive than others. By definition, however, an RfD takes into account sensitive groups, including children (16). Therefore, Chen et al.’s (1) conclusion that exposure via toys is “...special concern and further work is required to allow for accurate evaluation” is not supported by the available data on these compounds nor their reported hazard quotients of 4 × 10-9 to 8 × 10-3.
Disclosure of Conflicts of Interest M.B. has received honoraria from Albemarle Corporation for work on previous manuscripts. No form of remuneration was provided for his work herein. M.H. and T.S. are employed by Albemarle Corporation, a specialty chemical manufacturer whose product lines include BFRs. R.D.H. has no conflicts to declare. The views and opinions expressed in this article are those of the authors and not necessarily those of Institute of Public Health and Environmental Protection, University of South Florida, or Albemarle Corporation.
Literature Cited (1) Chen, S.-J.; Ma, Y.-J.; Wang, J.; Chen, D.; Luo, X.-J.; Mai, B.-X. Brominated flame retardants in children’s toys: concentration, composition, and children’s exposure and risk assessment. Environ. Sci. Technol. 2009, 43 (11), 4200–4206. (2) Kemmlein, S.; Hahn, O.; Jann, O. Emissions of organophosphate and brominated flame retardants from selected consumer products and building materials. Atmos. Environ. 2003, 37 (39-40), 5485–5493. (3) EPA. Exposure Factors Handbook (Final Report); EPA/600/ P-95/002F a-c; National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency: Washington, DC, 1997; http:// www.epa.gov/ncea/pdfs/efh/efh-complete.pdf (accessed October 27, 2009). (4) EPA. Child-Specific Exposure Factors Handbook (Final Report); EPA/600/R-06/096F; National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency: Washington, DC, 2008; http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_ id)484738 (accessed October 27, 2009). (5) NRC. Decabromodiphenyl oxide. In Toxicological Risks of Selected Flame-Retardant Chemicals; National Research Council; National Academy Press: Washington, DC, 2000; pp 7298; http://books.nap.edu/openbook.php?record_id)9841& page)R1 (accessed October 27, 2009). 10.1021/es903366p
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(6) Babich, M. A. CPSC Staff Preliminary Risk Assessment of Flame Retardant (FR) Chemicals in Upholstered Furniture Foam; Directorate for Health Sciences, U.S. Consumer Product Safety Commission: Bethesda, MD, 2006. (7) Hays, S. M.; Pyatt, D. W. Risk assessment for children exposed to decabromodiphenyl (oxide) ether (Deca) in the United States. Integr. Environ. Assess. Manage. 2006, 2 (1), 2–12. (8) Dungey, S.; Akintoye, L. Environmental Risk Evaluation Report: 1,1′-(Ethane-1,2-diyl)bis[penta-bromobenzene] (CAS: 8485253-9); SCHO0507BMOR-E-P; Environment Agency: Bristol, U.K., 2007. (9) Hardy, M.; Biesemeier, J.; Banasik, M.; Stedeford, T. Comment on “Alternate and new brominated flame retardants detected in U.S. house dust”. Environ. Sci. Technol. 2008, 42 (24), 9453– 9454. ¨ rn, U.; Eriksson, (10) Viberg, H.; Fredriksson, A.; Jakobsson, E.; O P. Neurobehavioral derangements in adult mice receiving decabrominated diphenyl ether (PBDE 209) during a defined period of neonatal brain development. Toxicol. Sci. 2003, 76 (1), 112–120. (11) Hardy, M.; Banasik, M.; Stedeford, T. Toxicology and human health assessment of decabromodiphenyl ether. Crit. Rev. Toxicol. 2009, 39 (S3), 1-44. (12) Viberg, H.; Fredriksson, A.; Eriksson, P. Changes in spontaneous behaviour and altered response to nicotine in the adult rat, after neonatal exposure to the brominated flame retardant, decabrominated diphenyl ether (PBDE 209). Neurotoxicology 2007, 28 (1), 136–142. (13) Johansson, N.; Viberg, H.; Fredriksson, A.; Eriksson, P. Neonatal exposure to deca-brominated diphenyl ether (PBDE 209) causes dose-response changes in spontaneous behaviour and cholinergic susceptibility in adult mice. Neurotoxicology 2008, 29 (6), 911–919. (14) Xing, T.; Chen, L.; Tao, Y.; Wang, M.; Chen, J.; Ruan, D.-Y. Effects of decabrominated diphenyl ether (PBDE 209) exposure at different developmental periods on synaptic plasticity in the dentate gyrus of adult rats in vivo. Toxicol. Sci. 2009, 110 (2), 401–410.
(15) Rice, D. C.; Reeve, E. A.; Herlihy, A.; Zoeller, R. T.; Thompson, W. D.; Markowski, V. P. Developmental delays and locomotor activity in the C57BL6/J mouse following neonatal exposure to the fully-brominated PBDE, decabromodiphenyl ether. Neurotoxicol. Teratol. 2007, 29 (4), 511–520. (16) EPA. IRIS Glossary; Integrated Risk Information System, National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency: Washington, DC; http://www.epa.gov/ncea/iris/ help_gloss.htm#r (accessed October 27, 2009).
Marek Banasik* Institute of Public Health and Environmental Protection, Warsaw, Poland
Marcia Hardy Health, Safety & Environment, Albemarle Corporation, Baton Rouge, Louisiana
Raymond D. Harbison Center for Environmental and Occupational Risk Analysis and Management, College of Public Health, University of South Florida, Tampa, Florida
Todd Stedeford Health, Safety & Environment, Albemarle Corporation, Baton Rouge, Louisiana * Corresponding author e-mail:
[email protected].
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