CORRESPONDENCE/REBUTTAL pubs.acs.org/est
Comment on “High Levels of Bisphenol A in Paper Currencies from Several Countries, and Implications for Dermal Exposure”
I
am writing regarding the paper by Liao and Kannan (“High Levels of Bisphenol A in Paper Currencies from Several Countries, and Implications for Dermal Exposure”).1 The paper reports that the estimated daily intake (EDI) values calculated for bisphenol A (BPA) from paper currencies were “several orders of magnitude” lower than the oral reference dose of 50 μg/kg bw/ day established by the United States Environmental Protection Agency and the European Food Safety Authority. The highest occupational (worst case) exposure was for paper currency from Brazil (their Table 2) where the mean EDI value was 21 ng/day. For a standard 60 kg body weight person, the worst case EDI is in fact over 140 thousand fold lower than the oral reference dose. This comparison does not take into account the lower rates of uptake of BPA from dermal versus oral exposures. See for instance ref 2. The authors conclude their paper by citing the 2010 Joint Food and Agriculture Organization (FAO)/World Health Organization (WHO) Expert Meeting on BPA3 as the source of studies reporting “adverse endocrine disruptive effects of BPA at doses as low as a few tens to a few hundreds of ng/kg bw/day,” concentrations which still exceed human exposure to BPA from paper currency by factors of 30 or more even in the worst case (Assuming 10 ng/kg bw/d as lowest effective dose and standard 60 kg bw person. Worst case EPI = 21 ng/day = 0.35 ng/kg bw/d. MOE = 10/0.35 = 28.6). The FAO/WHO Report itself does not include these studies among the low dose studies it considered as suitable for hazard characterization of BPA. Even among those studies, the report concludes that “there is considerable uncertainty regarding the validity and relevance of these observations” and “it would be premature to conclude that these evaluations provide a realistic estimate of the human health risk, given the uncertainties.” In short, the FAO/WHO Report does not support the authors’ claims of health effects at low doses. The FAO/WHO Report indicates that considerably more research will be required before studies claiming low dose effects of BPA can be accepted as valid for human health risk. This continues to be the view of regulatory authorities and independent research institutes worldwide, including most recently the Research Institute of Science for Safety and Sustainability of Japan.4 In the meantime, the current study demonstrates that even with the worst case BPA exposure level - occupational exposure to the currency with the highest level of BPA - exposure was 140-thousand fold lower than the oral reference dose, which in turn is based on multiple safety factors for lifetime exposure. The large margins of exposure (MOEs) that can be calculated between the oral reference dose and the BPA exposure level from currency in this new study firmly contradict claims of health risks from BPA in paper currency, as asserted by various activist groups.
’ AUTHOR INFORMATION Corresponding Author
*E-mail:
[email protected].
’ REFERENCES (1) Liao, C.; Kannan, K. High levels of bisphenol A in paper currencies for several countries, and implications for dermal exposures. Environ. Sci. Technol. 2011, 45, 6761–6768. (2) Biedermann, S; Tschudin, P.; Grob, K. Transfer of bisphenol A from thermal printer paper to the skin. Anal. Bioanal. Chem. 2010, 398 (1), 571–576. (3) FAO (Food and Agriculture Organization)/WHO (World Health Organization). Joint FAO/WHO Expert Meeting to Review Toxicological and Health Aspects of Bisphenol A. 2010. http://www. who.int/foodsafety/chem/chemicals/BPA_Summary2010.pdf (accessed August 16, 2011). (4) Kawasaki, H.; Kazaoui, R. Updated hazard assessment of bisphenol A. In The Research Institute of Science for Safety and Sustainability (RISS); National Institute of Advanced Industrial Science and Technology (AIST): Japan July 2011; Available from: http://www.aist-riss.jp/ main/modules/product/inde.phd?content_id=73&ml_lang=en.
John E. Heinze* Environmental Health Research Foundation r 2011 American Chemical Society
Published: September 28, 2011 9464
dx.doi.org/10.1021/es203169y | Environ. Sci. Technol. 2011, 45, 9464–9464
