STATS ARTICLES 2007
European Safety Review: No Risk from Bisphenol A Exposure
Trevor Butterworth, February 1, 2007
Expert scientific panel critical of many low-dose experiments cited by activists, San Francisco, for ban on chemical. Current exposure guidelines safe.
To environmental activists in the United States, the European Union is a beacon for aggressive and progressive regulation of environmental chemicals. By adopting the precautionary principle as a guide in its legislation governing the use of chemicals, known as Reach (Registration, Evaluation and Authorisation of Chemicals), Europe will require industries and businesses to demonstrate that the chemicals in products and processes are safe.
The E.U.'s Reach legislation was a model for San Francisco's ban on chemicals in children’s toys and baby bottles, which included bisphenol A (BPA), a chemical used to make polycarbonate plastic. The San Francisco Chronicle published an editorial endorsing the ban as “well intended” and called on the federal government to do more to protect children. As Time magazine reported:
"The controversy centers on a family of chemicals called phthalates (pronounced "thalates"), which are used to soften vinyl, and on bisphenol A (BPA), a substance used to make clear and shatterproof plastic. Most are known to be so-called endocrine disrupters, capable of interfering with the hormones that regulate masculinity and femininity. Several hundred animal studies have linked phthalates to prostate and breast cancers, abnormal genitals, early puberty onset and obesity. More recently, they've been shown to affect humans as well." 1
But now the European Union’s Food Safety Authority (EFSA) has just released a report, conducted by independent scientific experts, which not only reaffirms the safety of BPA, it sharply criticizes the methodology used in many of the low-dose exposure studies on rodents (which have formed the basis for activist attempts to have BPA proscribed). These conflict with recent tests more rigorously conducted using “comprehensive protocols” that did not show reproductive damage to rodents. The EFSA panel concluded:
“The Panel considered that low-dose effects of BPA in rodents have not been demonstrated in a robust and reproducible way, such that they could be used as pivotal studies for risk assessment. Moreover, the species differences in toxicokinetics, whereby BPA as parent compound is less bioavailable in humans than in rodents, raise considerable doubts about the relevance of any low-dose observations in rodents for humans. The likely high sensitivity of the mouse to oestrogens raises further doubts about the value of that particular species as a model for risk assessment of BPA in humans.
For these reasons, the Panel concluded that the overall NOAEL of 5 mg/kg bw/day, based on the results of a comprehensive three-generation study in the rat, identified in the SCF evaluation of 2002 is still valid, and in the Panel’s view is further supported by the NOAEL of 5 mg/kg bw/day in a recent two-generation reproductive toxicity study of BPA in mice. The NOAEL derived from the multigeneration study in rats was used by the SCF to derive a temporary TDI of 0.01 mg/kg bw, applying a 500-fold uncertainty factor, comprising 10 for interspecies differences, 10 for interindividual differences and 5 for uncertainties in the database on reproductive and developmental toxicity.”
It remains to be seen whether the activists, journalists, and politicians in the U.S. who are normally quick to cite Europe when it comes to imposing bans on chemicals revise their positions on BPA in light of this new report.
1. See STATS Time’s Toy Reporting Scares Parents
2. The panel was not able to address one recent study, reported in USA Today, which claimed that low dose exposure in mice resulted in chromosomal damage, but it did assess three multi-generational studies of rodents, which found no damage to fertility at much higher doses than those given to the mice in the study cited by USA Today. The level of chromosomal abnormality claimed in this study should have manifested in fertility problems. Additionally, the dose was given as a subcutaneous implant. The EFSA panel, it should be noted, does not consider this an appropriate method of exposure for assessing human risk.)