Is BPA Really Safe?

[Gus Van Horn blog]

By Gus Van Horn from Gus Van Horn,cross-posted by MetaBlog

As one who remembers the Alar scare of the late 1980s, I am hardly surprised that for all the government- and media-fanned panic about it, Bisphenol-A (BPA) is actually safe. Nancy McDermott of Sp!ked reports:

The Canadian ban and the subsequent panic has an almost Orwellian feel for anyone who actually follows scientific discussions of BPA. To appreciate fully the gulf between the public perception of risk and the reality, it is worth knowing something about the discussion of BPA among scientists. Scientists have been studying the chemical intensively for the better part of a decade since it was first suggested it might pose a risk to human health by Frederick vom Saal of the University of Missouri at Columbia. More than 4,000 studies and several major risk assessments later, scientists in the US, Japan and the European Union have exonerated it.

That sounds like old hat. McDermott also makes some interesting observations about why scientific evidence is getting short shrift in this latest panic:

It is of course very tempting to put these distortions down to journalists' predisposition for sensation, or perhaps to an environmentalist bias among some parents - but the story's grip on the public imagination suggests that there's more going on here. It is not that the facts are unavailable or that parents and journalists are incapable of grasping them. It’s more that it never occurs to them to be critical.

They are blinkered by a mistrust of the fruits of modernity and by deep pessimism about the future

. [bold added]

McDermott is on to something here, but she's not being hard enough on journalists -- or others on the continuum of intellectual occupations. Consider the following from some past commentary about environmentalist "safety" scares by Alex Epstein of the Ayn Rand Institute:

Environmentalists got the pesticide DDT and the apple preservative Alar off the market with claims that each causes cancer--based on studies using mice fed the equivalent of over 100,000 times normal human consumption. To "prove" that fossil fuels cause cataclysmic climate change--first, global cooling in the 1970s, now, global warming--environmentalists cite the predictions of wildly inaccurate computer models that, according to climatologist Dr. Patrick Michaels, perform "worse than a table of random numbers when applied to U.S. temperatures."

The environmentalists' proclamations of danger and doom are

not honest errors based on an overzealous concern for human safety and well-being--they are

a dishonest scare-tactic to make their anti-industrial policies appealing to those who do not share the environmentalist belief that nature should be preserved at human expense

. [bold added]

The "blinders" of which Ms. McDermott speaks are both the unfortunate long-term result of several generations of "progressive" education mixed with propaganda and the shorter-term effect of the overwhelming overexposure such environmentalist scares get in a news media dominated by altruist-collectivists -- who know, by the way, that the best way to stir panic is to imply that infants and children may be in danger.

In the long-term, we see the epistemology of the general public becoming less rational, and in the short-term we see that this is opening the public up to the active evil of environmentalists.

-- CAV

http://ObjectivismOnline.com/archives/003642.html

[brian0918]

So is it impossible for one to have a fear about ingesting a chemical, and decide to avoid it, without also hating industry? ...........

[brian0918]

Also, your Spiked article claims no BPA is found in blood, that it all safely flows out in the urine. Yet actual research finds it in blood, serum, breast milk, umbilical cord blood, semen, etc. So how did they come to such a wrong conclusion?

[~Sophia~]

This was my response in regard to this issue to an email send to me and other parents by the management of my son's school:

In recent years a number of researchers from government agencies, academia, and industry worldwide have studied the potential for low levels of BPA to migrate from polycarbonate products into foods and beverages. These studies consistently show that the potential migration of BPA into food is extremely low, generally less than 5 parts per billion, under conditions typical for uses of polycarbonate products.

Using these results, the estimated dietary intake of BPA from polycarbonate is less than 0.0000125 milligrams per kilogram body weight per day. This level is more than 4000 times lower than the maximum acceptable or "reference" dose for BPA of 0.05 milligrams per kilogram body weight per day established by the U.S. Environmental Protection Agency. Stated another way, an average adult consumer would have to ingest more than 600 kilograms (about 1,300 pounds) of food and beverages in contact with polycarbonate every day for an entire lifetime to exceed the level of BPA that the U.S. Environmental Protection Agency has set as safe.

Edited July 15, 2008 by ~Sophia~

[KendallJ]

So is it impossible for one to have a fear about ingesting a chemical, and decide to avoid it, without also hating industry? ...........

Yup, if the fear is arbitrary, or even worse, not supported by the data.

Also, your Spiked article claims no BPA is found in blood, that it all safely flows out in the urine. Yet actual research finds it in blood, serum, breast milk, umbilical cord blood, semen, etc. So how did they come to such a wrong conclusion?

Well, let's be clear. As limits of detection increase, EVERYTHING will be found everywhere at some point. "Coming to such a wrong conclusion" is a poor way to characterize this if the actual levels are incredibly small and they are so distant from any levels that have been shown to have health effects that it renders the levels irrelevant. There is very little difference in this case between, "all safely flows out" and "safely flows out."

[~Sophia~]

So is it impossible for one to have a fear about ingesting a chemical, and decide to avoid it, without also hating industry? ...........

No, but...

Water is toxic in large quantities. Often, in mental institutions there is no unlimited access to water because patients can use it as a drug - aiming for a mental buzz arising from overhydration (which is life threatening).

My point is that dosage is an important factor when determining the level of harm of any chemical.

Edited July 15, 2008 by ~Sophia~

[musenji]

This was my response in regard to this issue to an email send to me and other parents by the management of my son's school:

Wanna hear something ironic? The numbers you quoted look right along the lines of what New-Age folks believe will CURE people of the effects--under the "theory" of homeopathy. (Homeopathy is the idea that if you take a poisonous substance and distill it millions of times in water, the result will be the cure for whatever ailment the poison causes.)

So any of the environmentalists who subscribe to homeopathic remedy should be PRAISING this.

[brian0918]

This was my response in regard to this issue to an email send to me and other parents by the management of my son's school:

That article I linked to in my second post concludes that humans must be getting exposed to at least 10 times what the EPA has deemed safe based on the amount of the chemical detected in tissue and blood samples. (cited in turn from Scientific American)

Edited July 16, 2008 by brian0918

[~Sophia~]

FDA statement, January 29, 2008

The Agency's current position on the presence of BPA impurities in food-contact polymers is as follows. BPA is used in the manufacture of two types of polymers used for food-contact articles (i.e., polycarbonate (PC) polymers and epoxy-based enamels and coatings) and is present at very low levels in the finished food contact materials. Typical uses of PC polymers include food processing equipment, such as popcorn makers, and water and infant baby bottles intended for repeated use. BPA-based epoxy coated cans are used in a variety of canned food and beverage applications, including cans used to hold infant formula. The Agency is aware of several reports stating that BPA has estrogen-like activity. However, there are other reports that appear to dispute any reason to expect harm at the low exposures that humans experience. A March 2007 report from a consumer group included studies showing the levels of BPA found in canned foods and migrating out of PC baby bottles and included claims that these levels are unsafe. FDA scientists have reviewed the available information from this report and have concluded that the BPA levels found in canned foods or migrating out of PC baby bottles are not significantly different than the very low levels previously found by FDA chemists and other laboratories, levels that result in a dietary exposure that is orders of magnitude below the levels known to not cause toxic effects in animals.

The agency has been actively reviewing the safety of BPA and has completed a review of the available data obtained from animal studies, and migration studies. Based on the results of the migration studies conducted by FDA chemists, we have determined that the dietary exposure to BPA is low (3.7 ppb), the level that is orders of magnitude below the levels known to cause toxic effects in animals. Considering the low dietary exposure and the fact that BPA had not demonstrated adverse effects when consumed by animals in amounts of much higher (orders of magnitude) than humans would consume, FDA sees no reason at this time to ban or otherwise restrict the uses now authorized. Our conclusion is based on our ongoing review of all available data. We will continue to monitor data on BPA to determine if its use would raise a safety concern. If such a concern exists, FDA will take the appropriate post-market regulatory action.

Edited July 16, 2008 by ~Sophia~

[~Sophia~]

That article I linked to in my second post concludes that humans must be getting exposed to at least 10 times what the EPA has deemed safe based on the amount of the chemical detected in tissue and blood samples. (cited in turn from Scientific American)

Let's look at the source. This is the article.

This is their conclusion:

Therefore, these models indicate that i) humans are exposed to BPA at

a much higher level than has been estimated from known exposure sources, and/or ii)

Humans are exposed through multiple routes, making the metabolic response different

from that observed in animal models, and/or iii) metabolism of BPA following chronic,

low-dose exposure is not predicted by the acute high-dose studies used to generate the

current pharmacokinetic models.

First note that this is a model based on high dose studies in rodents and that higher level of exposure is not the only possible explanation.

I will quote few more things from that article (pay attention to the units - remember safe dose is 50 micrograms/kg body weight/day):

A few studies have used BPA measurements in urine to estimate current

levels of exposure; Ouichi & Watanabe, using early morning urine samples collected

from 48 women and analyzed by HPLC coupled with coulometric electrochemical

detection, estimated current intake at 0.6-71.4 micrograms/day.

Observational study performed by the same group of

investigators examined BPA exposures in 257 preschool children [40]. This study

verified that BPA could be found in more than 50% of indoor air, hand wipe, solid food

and liquid food samples. This study’s results suggested that 99% of exposures of

preschool children originated in the diet; the estimated exposure from dietary sources

was 52-74 ng/kg per day, and estimated inhalation exposure was 0.24-0.41 ng/kg per

day.

1 nanogram = 0.001 micrograms

Using literature from contamination in the environment (water, air, soil) and food contamination (can surfaces, plastic containers), the daily human intake of BPA was estimated at less than 1 microgram/kg body

weight/day [44]. Alternatively, the European Commission’s Scientific Committee on

Food [45] estimated BPA exposure to be 0.48-1.6 micrograms/kg body weight/day from

food sources, while Thomson et al. estimated that New Zealanders consume as much

as 4.8 micrograms/day from dietary sources alone [46].

Based on these measured levels of leaching, average dietary exposure to BPA

was estimated for infants from birth through 3 months of age, the period when infants

consume exclusively liquid foods [48]; these calculations estimated that newborns,

because of their lower body weight, are exposed to the highest levels of BPA (24

14 micrograms/kg body weight/day). By 3 months of age, dietary exposure estimates drop

to 15 micrograms/kg body weight/day.

--------

The metabolic elimination pathways for BPA need to be considered for human

risk assessment. However, only a limited number of human studies have addressed

these issues...

They have no good conclusive metabolic/kinetic data for humans.

In contrast, many studies have been dedicated to addressing the question of

BPA metabolism in animal models, particularly rodents (Table 6). However, a major

weakness to current metabolic studies is that, while current evidence indicates that

humans are experiencing multiple exposures each day, virtually all of the current

metabolic studies are based on kinetics following a single, usually high dose

Finally, they commented on health effects:

...human studies of possible health effects of BPA exposure are extremely limited...

Although providing interesting preliminary data on potential health risks, these

epidemiology studies have several limitations. Overall, the studies have small sample

sizes, limited details on subject selection criteria, and they generally are cross-sectional

designs that include limited control for potential confounders. These limitations in design

contribute to the limited ability to make conclusions based on the epidemiology of

potential health risks of BPA. Finally, due to their design, it was not possible to

determine whether altered BPA metabolism is a secondary effect due to the

dysfunctions and conditions examined in these studies.

Edited July 16, 2008 by ~Sophia~

[brian0918]

Thanks for finding an actual, readable version of that article. I'll take a look at it and your post when I get some more time.