On April 23, 2014, the European Food Safety Authority (EFSA) invited stakeholders to discuss the draft scientific opinion on human exposure to BPA published in summer 2013 and the draft opinion of human health risks published in January 2014 (previously reported on by the FPF). The meeting aimed to clarify comments received during the public consultations and offered an opportunity for stakeholders from industry, governmental and non-governmental organizations (NGOs) and academia to elaborate on their comments submitted to EFSA. EFSA received around 250 comments for each of the draft opinions with around 20 and 30 % of comments coming NGOs and industry associations, respectively. The remaining comments came from national agencies, academia and individuals. While EFSA received positive feedback on its weight of evidence (WoE) approach and the use of a human equivalent dose (HED), commenting parties criticized the fact that 75% of data originated from France, the inclusion of a Japanese study on exposure through breast milk using the ELISA method, the quantitative estimation of dermal exposure, the heavy reliance on the Teeguarden et al. study (2011), and the exclusion of prenatal, occupational, medicinal, dental and sublingual exposures.
During the first part of the meeting, stakeholders commented on EFSA’s health risk assessment of BPA. Donald Prater from the U.S. Food and Drug Administration (FDA) stated that the U.S. agency recommended the maintenance of the former tolerable daily intake (TDI) of 50 µg/kg body weight (bw)/ day (d). He criticized the fact that that even though EFSA included more data in the new assessment, the uncertainty increased as well. Furthermore, the FDA considered the calculation of an HED inappropriate when toxicokinetics remained uncertain and argued that the full scientific opinion should address potential contamination sources to resolve inconsistencies between and within studies.
In the following presentation, Gwynne Lyons from the NGO ChemTrust considered that there was sufficient evidence for possible harm arising from BPA exposure, which was not reflected in the draft opinion. She stressed that the summary in the draft opinion should elaborate more on the uncertainties involved in the risk estimates, and should address the implications of EFSA drawing the wrong conclusions. Lyons further pointed out that the evidence on mammary gland effects supports an even lower TDI than the currently proposed temporary TDI (t-TDI) of 5 µg/kg bw/ d.
Dieter Beyer from PlasticsEurope indicated that the trade association considered the dermal exposure estimates sufficiently conservative and expressed appreciation for the systematic data evaluation. However, he agreed with the U.S. FDA that the current TDI should be maintained and suggested combining left and right kidney weight as well as rat, mouse and monkey data when deriving the most sensitive benchmark dose estimates.
Ulla Hass from the Danish Technical University (DTU) agreed that the report was conservative for kidney effects but criticized the exclusion of other relevant endpoints. She indicated that BMD modeling may not be appropriate for non-continuous data such as mammary development toxicity. Similarly, male sexual development was excluded in the assessment and Hass disagreed that fertility was a gold standard for sexual development. She pointed out that in contrast to humans, rats generate more offspring and have a larger sperm reserve. Further, such a gold standard ignores the importance of other reproductive toxicity endpoints, including malformations, hypospadias, decreased penis length and increased risk of prostate cancer. According to her, the data presented on mammary and male sexual development support a TDI of 0.7 ug/kg bw/d or lower.
Robert Smith from the Committee on Toxicity (COT), an advisory committee to the UK government, recommended more research on non-monotonic dose response relationships and further work on absorption and metabolism for dermal exposures to BPA. In the concluding discussion, Gwynne Lyons pointed out that the NIEHS study, from which EFSA’s draft opinion draws heavily, had contaminated controls, making it impossible to decide whether there were truly no effects at low doses.
The second part of the meeting addressed the exposure assessment carried out by EFSA (previously reported on by the FPF). Paul Whaley from Message Wright reported on his analysis of the scientific robustness of the literature review carried out by EFSA and concluded it to be unsatisfactory. He addressed specific points, including the use of a protocol, declaration of interest, search strategy and the selection criteria for studies, and suggested, among other recommendations, that EFSA publish a protocol before carrying out a risk assessment. Another suggestion he made was to transparently document the panel’s decisions.
Beate Kettlitz from the industry association FoodDrinkEurope questioned whether the samples used for the exposure estimates were collected evenly throughout time and whether the data were representative for Europe, with 75% coming from France.
Finally, Anne-Laure Demierre from the Swiss Federal Office for Public Health criticized that the study by Biedermann et al. (2010) exploring the dermal transfer of BPA did not follow Organisation for Economic Co-operation and Development (OECD) Good Laboratory Practice (GLP) guidelines, and suggested the use of a study she carried out together with colleagues which assessed the transfer of BPA across the skin (Demierre et al 2012). A member of the EFSA CEF Panel clarified that for the opinion on BPA studies were appraised irrespective of their compliance or not with GLP or OECD guidelines applying the same evaluation criteria in order to conclude on their reliability and relevance for risk assessment. Demierre further questioned whether the monitoring studies on occupational exposures did not overestimate exposure assuming a 24-hour exposure rather than 8 to 10 hours, representative of an average work day of cashiers.
Concluding the meeting, Anthony Hardy, Chair of the EFSA Scientific Committee, pointed out that EFSA created two new working groups (WGs) addressing weight of evidence approaches and how to determine an adverse effect. The power point slides presented during the meeting will become publicly available on EFSA’s website in May 2014. Furthermore, a technical report including all comments submitted to EFSA will be published together with the final opinion on the BPA risk assessment, which is due by the end of 2014.
EFSA (April 23, 2014). "Bisphenol A: EFSA welcomes engagement with stakeholders."
FPF article "EFSA publishes draft BPA opinion, part I"
FPF article "EFSA publishes draft BPA opinion, part II"
Biedermann, S., et al. (2010). "Transfer of bisphenol A from thermal printer paper to the skin." Analytical and Bioanalytical Chemistry 398(1):571-6.
Demierre, A-L, et al. (2012). “Dermal penetration of bisphenol A in human skin contributes marginally to total exposure.” Toxicology Letters 18;213(3):305-8.
Teeguarden, J. et al. (2011). ”Twenty-four hour human urine and serum profiles of bisphenol A during high- dietary exposure.” Toxicological Sciences 123(1):48-57.