The US Environmental Protection Agency has issued a request for public comment on possible toxicity testing and environmental sampling to study the potential environmental impacts of bisphenol-A (BPA).
BPA is used in the manufacture of a wide range of consumer and industrial products, including food-can liners, polycarbonate plastics, epoxy paints and coatings and thermal papers.
Releases of BPA to the environment exceed 450 tonnes per year, according to the Agency.
EPA is consulting on whether to carry out toxicity testing for BPA in environmental organisms, and whether to require sampling and monitoring in areas around possible BPA releases to see whether these organisms are being exposed to BPA at levels that could cause adverse reactions.
This proposal is quite separate from EPA’s work on BPA and human health, according to the Agency’s advance notice of proposed rulemaking (ANPRM):
“This ANPRM is directed only toward the environmental presence and environmental effects of BPA.
EPA is working with the Department of Health and Human Services (HHS) on potential human health issues, but is not considering any additional testing specifically in regard to human health issues at this time.”
Interested parties have until 26 September to submit evidence that could influence EPA’s decision.
For most people, the biggest exposure to BPA is from food, rather than the environment. In Europe, BPA exposure is limited to a tolerable daily intake (TDI) of 0.05 mg/kg of bodyweight, after established testing procedures identified a range high-dose toxicity issues, including reproductive and developmental problems.
Some more recent studies appear to show effects at much lower doses, including sex-specific neurodevelopment, anxiety, changes in mammary glands and prostate in rats and impaired sperm.
But an expert meeting hosted by the World Health Organisation and the UN’s Food and Agriculture Organisation in November concluded that:
“There is considerable uncertainty regarding the validity and relevance of these observations.
While it would be premature to conclude that these evaluations provide a realistic estimate of the human health risk, given the uncertainties, these findings should drive the direction of future research with the objective of reducing this uncertainty.”
Similarly, the European Food Safety Authority (EFSA) reported in its latest review of the evidence in September 2010 that: “Some recent studies report adverse effects on animals exposed to BPA during development at doses well below those used to determine the current TDI… However, these studies have many shortcomings.
At present the relevance of these findings for human health cannot be assessed.”
EFSA also reported that some human epidemiological studies suggest associations between exposure to BPA and coronary heart disease and reproductive disorders, but concluded that the studies were not designed in a way that could establish a cause and effect relationship.
The controversy led earlier this year to a ban on BPA in polycarbonate baby bottles within the EU. Canada is also moving forward with a ban.