Fears have been growing that some chemicals could mimic hormones produced by the endocrine systems of humans and animals, with potentially disruptive effects. Bisphenol-A, which is a weak mimic of the sex hormone oestrogen, is used in plastic resins such as polycarbonate and epoxy resins, both of which are used in food contact applications. Evidence of actual hormone-like effects from bisphenol-A in rodents was first published in 1996. This was followed by a second study in 1997 which suggested that it could mimic hormones in mice at very low concentrations (ENDS Daily 27 March 1997).
CEFIC and the SPI have now reported a new study that has failed to replicate the 1997 results. The groups say that repeat experiments found bisphenol-A had no effect at doses identical to the earlier study of 2 or 20 micrograms per kilogram of body weight per day (ug/kg/day), nor at doses ten times higher or lower.
The new study's immediate implication, according to CEFIC and the SPI, is that it removes suspicions that bisphenol-A used in food contact packaging could risk hormone disruption in humans. They conclude that the new results "do not support the theory that low oral doses of bisphenol-A pose a health concern to humans or the environment".
Migration of bisphenol-A from can coatings was estimated to be no more than 37 parts per billion (ppb), compared with an EU migration safety limit for foods of 3 parts per million (ppm). Dietary intake of bisphenol-A from metal cans and polycarbonate containers used to package food or drink is no more than 0.118 ug/kg/day, it concludes. This compares with the US "reference" low risk dose of 50 ug/kg/day.
The study's broader implication, according to CEFIC and the SPI, is that it undermines the "low dose hypothesis," which states that hormone-like substances might have effects at exposure levels below those previously defined as "no observed effect levels" (NOEL).
The results have yet to be peer reviewed and are not conclusive. However, they do provide an important challenge to the low dose hypothesis and suggest that risks from very low exposure to chemicals with weak hormone-like effects may have been overstated.
CEFIC, tel: +32 2 676 7211.
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