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April 17, 2008
“The reported levels of BPA in human fluids are higher than the BPA concentrations reported to stimulate molecular endpoints in vitro and appear to be within an order of magnitude of the levels needed to induce effects in animal models”.
Taken as a whole, these reviews include data from almost 200 different studies and provide strong evidence of the link between BPA exposure during early life and adverse health effects ranging from reproductive dysfunction and cancer to behavioral problems.
BPA leaches from reusable plastic water bottles: A recent study from researchers at the University of Cincinnati found that reusable water bottles that are commonly used by millions of people every day leach BPA under normal conditions of use (Le 2008).
The researchers found that BPA leached into water that was stored within these bottles and that leaching rates were independent of the age of the bottles.
However, when hot water (100 degrees Celsius) was stored in these bottles, as might commonly occur during cold weather activities, leaching rates increased 15 to 55 fold, with rates ranging from 8 to 32 ng/hour.
In the most recent CDC biomonitoring study, researchers found BPA in the urine of 93% of almost 2,500 Americans ages six and older who are representative of the US population (Calafat 2008). Sources of exposure varies from individual to individual but this study from the University of Cincinnati suggests that for a significant number of people, reusable plastic bottles may contribute a considerable portion to their daily BPA intake. This study also adds to the body of research that confirms the ubiquitous presence of this chemical in a variety of products that people use on a daily basis.
There is now a movement within the marketplace to provide water bottles that are BPA free; there are also baby toys and bottles, sippy cups, and a number of other products that are marketed as “BPA free”. This suggests that in many of its current uses, BPA can easily be substituted with safer alternatives. However, these exclusive products are only available to those who are aware of the health concerns related to BPA exposure, and those that have the means to afford these products. Listing BPA under Proposition 65 as a developmental and reproductive toxin would encourage manufacturers to adopt safer alternatives or at least warn consumers of the risks associated with use of their products.
New research confirms relevance of BPA studies that used non-oral routes of administration: Many of the studies that illustrate BPA’s low dose toxicity have used non-oral routes of administration. The relevance of these studies for human exposures was recently confirmed by researchers from the University of Missouri, who conducted a study in which they administered BPA to two different groups of neonatal mice by either oral or subcutaneous routes (Taylor 2008). They found no significant difference in plasma levels of unconjugated BPA, leading study authors to conclude “the large numbers of BPA studies that used non-oral administration at very low doses during the neonatal period should not be dismissed by scientists or the regulatory community based on the route of administration”.
In summary, these recent developments and new studies add to a growing body of research that clearly illustrate the potential health risks associated with BPA exposure. Especially of concern are exposures among the developing fetus, infants, and children; recent CDC biomonitoring data revealed that children ages 6 to 11 years had least square geometric mean concentrations (LSGM) of BPA in urine that were almost double that in adults (4.5 micrograms/liter vs. 2.5 micrograms/liter) (Calafat 2008). This study did not include participants younger than age 6.
In addition to these recent developments, there are a few other important points that we would like to bring to your attention:
Sincerely, Anila Jacob, M.D., M.P.H.
Senior Scientist
Environmental Working Group
April 17, 2008
Ms. Cynthia Oshita
Office of Environmental Health Hazard Assessment
Proposition 65 Implementation
P.O. Box 401
1001 I Street, 19th Floor
Sacramento, CA 95812-4010
- With regards to exposure, NTP notes “Although biomonitoring data are not available for infants and children less than 6 years of age, blood and urine levels of free bisphenol A are predicted to be higher in these age groups” (NTP 2008).
- NTP notes “there is some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures. The NTP also has some concern for bisphenol A exposure in these populations based on effects in the prostate gland, mammary gland, and an earlier age for puberty in females” (NTP 2008).
- NTP concludes, “the possibility that bisphenol A may alter human development cannot be dismissed” (NTP 2008).
- Infant formula manufacturers do not adequately test for BPA in their products to ensure their safety.
- FDA has based its public assurances of the safety of BPA-containing consumer products on just 2 industry studies, one of which is unpublished.
- Several recent studies that highlight the links between BPA exposure and adverse health effects have been published.
- New research shows that commonly used plastic water bottles leach BPA under typical conditions of use.
- New research confirms the relevance of low-dose BPA studies that use nonoral routes of administration.
- Current body of literature: To date, almost 100 animal studies have been published in peer reviewed journals that show significant adverse health effects related to BPA exposures that fall below the current ‘lowest adverse effect level’ (LOAEL) for BPA of 50 mg/kg/day defined by EPA (EPA 1993). These independent studies originated from scientists and labs at academic institutions and government agencies from all over the world. In many of these studies, exposure occurred in-utero and adverse health effects were observed in offspring. As a whole, these studies illustrate that BPA has adverse effects on diverse systems within the body, ranging from the immune system, to the reproductive, neurological, and endocrine systems.
- Adverse health effects related to BPA exposure mirror US health trends: In animal studies, BPA exposure at low doses has been linked to structural changes in mammary and prostate tissues that result in cancer later in life, in addition to a number of other adverse health effects including impaired fertility, insulin resistance, and recurrent miscarriage. These findings are especially worrisome in light of current US health trends since all of these adverse health effects are either on the rise or common among our population. While we may never have definitive epidemiological evidence showing cause and effect, the fact that the vast majority of Americans are chronically exposed to BPA, coupled with current health trends provides a compelling reason to exercise the precautionary principle.
- NIH sponsored panel finds concern: An NIH sponsored panel consisting of 38 BPA experts has expressed strong concerns about the risks to human health posed by current BPA exposures. In their consensus statement, they note the following “The published scientific literature on human and animal exposure to low doses of BPA in relation to in vitro mechanistic studies reveals that human exposure to BPA is within the range that is predicted to be biologically active in over 95% of people sampled. The wide range of adverse effects of low doses of BPA in laboratory animals exposed both during development and in adulthood is a great cause for concern with regard to the potential for similar adverse effects in humans. Recent trends in human diseases relate to adverse effects observed in experimental animals exposed to low doses of BPA. Specific examples include: the increase in prostate and breast cancer, uro-genital abnormalities in male babies, a decline in semen quality in men, early onset of puberty in girls, metabolic disorders including insulin resistant (type 2) diabetes and obesity, and neurobehavioral problems such as attention deficit hyperactivity disorder (ADHD)” (vom Saal 2007).
Sincerely, Anila Jacob, M.D., M.P.H.
Senior Scientist
Environmental Working Group
References:
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