by Delores Broten
In October, the Canadian government broke the mould and followed through on its announcement of the first measures in the world to control exposure to bisphenol A (BPA). The chemical will be banned from baby bottles because of its effects on the development of young children.
The government said that there was no scientific proof that the compound, added to hard plastics of all sorts from drinking bottles to cds, as well as epoxies andinks, was harmful to adults.
Health Canada will also determine limits on the amount of BPA leaching from tins at some time in the future. Because the compound is ubiquitous in the environment and extremely toxic to aquatic organisms, the government is also going to require waste water effluents to meet limits on the amount of BPA dumped. No other steps to control BPA are contemplated.
The Health Canada assessment was published in April 2008. However, not only did the assessment omit many published studies in its discussion, but new research findings against the chemical continue to mount.
• A new study published in the Journal of the American Medical Association in September found an association between bisphenol A exposure at the high end of normal population levels and adult-onset diabetes and cardiovascular disease.
• According to a Californian study, published in April in Cancer Research, many genes in non-cancerous breast cells exposed to trace amounts of bisphenol A begin acting in a way that closely resembles gene activity in highly aggressive breast tumours.
• A study published in the Proceedings of the National Academy of Sciences in September showed that, in a primate exposed to a daily dose equal to the current US safe daily limit, bisphenol A interfered with the formation of some types of synapses in the brain: “Because remodeling of spine synapses may play a critical role in cognition and mood, the ability of BPA to interfere with spine synapse formation has profound implications. This study is the first to demonstrate an adverse effect of BPA on the brain in a nonhuman primate model and further amplifies concerns about the widespread use of BPA in medical equipment, and in food preparation and storage.”
• In October a study in Environmental Health Perspectives stated that bisphenol A induces a group of proteins that protect cancer cells from the toxic effects of chemotherapy. University of Cincinnati researchers exposed human breast cancer cells to low levels of BPA consistent with levels found in the blood of human adults.
Meanwhile, the US scene was convulsed by a congressional inquiry into chemical industry influence on Food and Drug Administration safety assessments for BPA, and Californian law makers again narrowly rejected a ban on BPA in children’s products in the midst of a multi-million dollar chemical industry ad campaign. The National Toxicology Program expressed concern about low level exposure to BPA. In July the European Food Safety Authority declared that BPA was safe because humans, including mothers and newborns, metabolize and eliminate BPA more rapidly than do rats. Other scientists pointed out that there was little information about human metabolism of BPA.
Given these controversies, it looks like it will be awhile before the rest of the world screws its courage to the sticking point and stuffs BPA back into the chemical factories it is pouring out of.
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[From WS November/December 2008]
