By Sarah (Steve) Mosko
Special to the Surf City Voice
It would have been hard to get through 2010 without bumping into some scary information about the plastic ingredient bisphenol A, a.k.a. BPA, like the fact it leaches from polycarbonate baby bottles and sports bottles and metal food can linings into the contents or that it is widespread in the dye on thermal cash register receipts and is absorbed through human skin.
Adding to such anxieties about environmental toxins, Japanese researchers have recently honed in on a chemical very similar to BPA dubbed BPAF, or bisphenol AF, that might be even more dangerous than BPA. The “F” stands for fluorine, and the two substances are identical except for the substitution of six fluorine atoms in BPAF for six hydrogens in BPA (see below).
In part, it was knowledge that certain properties of fluorine might intensify the molecule’s reactivity that drew the researchers’ attention to BPAF, as there are additional chemicals out there that resemble BPA too.
The risks of exposure to BPA stem from the fact that it is an endocrine disruptor that mimics the actions of the hormone estrogen. Over 200 laboratory studies have linked low-dose BPA exposure to a host of health effects including reduced sperm production and infertility, cardiovascular disease, diabetes and derailed development of the brain and prostate gland.
Natural hormones like estrogen act on specific receptors throughout the body in a lock and key fashion to either turn on or off genes that control a host of bodily functions like the development of sex characteristics and ovulation. Endocrine disrupting chemicals play havoc with normal physiology by either mimicking or blocking the action of natural hormones on their receptors.
In humans, there are multiple sub-types of the estrogen receptor, so the impact of environmental chemicals which mimic estrogen will vary depending on which sub-types they can lock onto.
Whereas BPA is known to bind selectively to the “gamma “estrogen receptor in the nucleus of cells where DNA is housed, the research reported by the Japanese researchers in the online April 28, 2010 issue of Environmental Health Perspectives indicated that BPAF delivers a double whammy in that it is many times more potent than BPA at two different receptor sub-types, behaving like estrogen at the “alpha” sub-type but blocking estrogen’s effect at the “beta” sub-type.
This double action of BPAF is worrisome because alpha and beta receptors are widespread in the body of both men and women: alpha receptors predominate in the uterus, liver, kidney and heart, whereas beta receptors are found primarily in the ovaries, prostate, lungs, gastrointestinal tract and bladder. BPAF could upset vital regulatory functions performed by estrogen within any of these organs.
Widespread human contamination with BPA is now well-documented, and sufficient evidence has accumulated in the last decade that low-dose exposure to BPA represents a significant health risk that Canada, the European Union and eight U.S. states (but not California) have banned BPA from various childcare products. BPAF, though, has not been studied for toxicity to humans or animals, nor does anyone know the extent to which humans are already exposed although it is assumed that far more BPA is being produced than BPAF.
However, a 2008 report from the U.S. government’s National Toxicology Program notes that the fluorine in BPAF is likely to make it more persistent in the environment and also points to a study which found BPAF in the fat tissue of women, raising concerns it could be passed along to fetuses.
The same report informs that BPAF, like BPA, is used in polycarbonate plastics, epoxy resins and in components of equipment for processing food and pharmaceuticals. Other sources mention its use in electronic devices and optical fibers. Given that information about the use of BPAF in any specific product would be considered proprietary, the consumer has no way to identify items which might contain it.
As is true for nearly all of the estimated 84,000 chemicals in commerce today, BPA was unleashed on the public without prior health safety testing. Millions of research dollars have since been spent to uncover the threats to public health and wildlife from BPA exposure, and many more dollars will follow before the full story on BPA is known. Early signs suggest BPAF might follow the same course.
Both BPA and BPAF are timely examples of why a drastic overhaul of federal regulation governing chemical safety is sorely needed. The Toxic Substances Control Act of 1976 (TSCA), which sets national policy concerning regulation of chemicals, is seriously out-of-date and lacks the muscle to hold industry responsible for the health safety of the thousands of new chemicals that go into production each year. By effectively allowing industry to use the public as guinea pigs to test whether new chemicals pose any health risks, the federal government has shirked its fundamental responsibility to safeguard its citizenry.
California and the European Union have already taken legislative actions to embrace the “precautionary principle” which stipulates that chemicals need be proven safe before being let loose onto an unsuspecting public. The U.S. government should follow their lead.
Legislation was in fact introduced by Democrats into both houses of the U.S. Congress in 2010 which would shift the burden onto industry of demonstrating the safety of chemicals they employ and also increase the authority of the Environmental Protection Agency to place restrictions on substances deemed risky to the public.
What the conservative shift in Congress which emerged from the 2010 mid-term elections will mean for such efforts to modernize the TSCA remains to be seen.