[Pharmwaste] Plastics in Our Diet: The Need for BPA Regulation

[DeBiasi,Deborah]

Special Editions -  October 3, 2008
http://www.sciam.com/article.cfm?id=plastics-in-our-diet


Plastics in Our Diet: The Need for BPA Regulation

When scientists find chemicals that disrupt human systems, regulators
must ban them
By Sheldon Krimsky 

Studies have surfaced in recent months that certain plastic products we
use every day could be interfering with our hormone systems.
Approximately 100,000 synthetic chemicals are approved for consumer
products and industrial processes-and certain classes of them, it seems,
are dangerous to our health. One compound in the news, known as BPA, is
of particular concern.

Only a handful of once approved substances have ever become banned or
severely restricted, such as DDT, PCBs and benzene. What about the rest?
Under existing laws, drugs must be shown to be safe and effective,
pesticides must be tested to demonstrate that they are safe enough in a
balance between risks and benefits, and synthetic food additives must
meet a standard set in 1958 by the Delaney Amendment to the Food, Drug
and Cosmetic Act. But many, many other substances remain untouched by
safety regulations.

According to the Delaney Amendment, if a synthetic food additive causes
cancer in test animals at any dose it must be prohibited. This is a
precautionary test: people are not typically exposed to the high doses
given to lab rats, and if the animals get cancer that does not guarantee
that humans exposed to lower doses will suffer the same fate. But
society has determined that such a risk is not worth taking given that
artificial food additives are not a necessity.

The amendment does not apply to other synthetic chemicals that find
their way into our foods. Yet plastic monomers and polymers-notably
bisphenol-A, phthalates and polyvinyl chloride-can leach into our food
from baby bottles, plastic wraps, water bottles, soda can liners and
certain plastic containers that are heated in a microwave. The few
health and safety laws that are marginally pertinent to such chemicals
are not nearly as precautionary. Typically the burden of proof is on the
regulators to show that synthetic molecules are dangerous to human
health or the environment. Manufacturers do not have to demonstrate that
a compound is safe.

In the 1950s bisphenol-A, or BPA, became a key component in
polycarbonate plastics-used in those durable plastic baby bottles, the
ubiquitous Nalgene water bottles, the epoxy lining in canned food, as
well as dental implants and eyeglass lenses. More than two billion
pounds of BPA are produced in the U.S. every year. Hundreds of
scientific articles published in peer-reviewed journals for decades have
demonstrated that BPA can produce adverse health effects in test animals
at very low doses and provided circumstantial evidence that it can harm
humans. A 2007 consensus statement from a 38-member scientific panel in
the journal Reproductive Toxicology concluded that there was "great
cause for concern" about the potential for adverse effects in humans.
Health Canada announced this past April that BPA is "toxic to human
health." Yet U.S. regulators have not been persuaded to ban it from
consumer goods. The reason is that they maintain an unrealistically high
burden of proof.

Bisphenol-A is a demonstrated endocrine disruptor: it interferes with
the hormone systems of animals, including humans. Evidence dates back to
the 1930s. In recent tests, when pregnant mice were exposed to very
small quantities (two parts per billion), the male offspring had
dramatically enlarged and hypersensitized prostates when they reached
adulthood. Prenatal exposure of lab rats to extremely low doses of BPA
makes them more susceptible to cancer, too. BPA can also inhibit the
treatment of human prostate cancer, and babies born to women with
elevated phthalate levels are demasculinized. These links have prompted
scientists to hypothesize that these and other endocrine-disrupting
compounds may be key factors in certain reproductive and developmental
disorders, such as early onset of puberty in girls, decline in semen
quality, genital abnormalities, and even neurobehavioral problems such
as attention-deficit hyperactivity disorder.

As a result, Playtex Infant Care announced in April it would eliminate
BPA from its line of baby bottles, and Nalge Nunc International said it
would pull its Nalgene Outdoor water bottles from stores. Chains such as
Wal-Mart and Toys "R" Us said they would stop carrying certain products.
Senator Charles Schumer of New York introduced a bill to ban BPA in
children's products.

People opposed to removing BPA from consumer goods argue that mice are
not humans, and until we have definitive evidence (whatever that might
be) that it harms humans, there is no reason to prohibit its use.
Ethically, we cannot test humans by exposing them to BPA, and because
the chemical is ubiquitous, we cannot perform a credible case-controlled
study by separating people who are exposed to it from those who are not.

What we do know is that the BPA molecule attaches to a hormone receptor
on cells in our body. We also know that BPA is biologically active; our
bodies do not simply break it down and expel it. We are not certain what
it does to our hormone receptors: Does it block them from receiving
natural hormones? Does it activate a harmful DNA reaction? Does it do
this only to certain people at certain ages?

Do any of these questions really matter? Is it not enough to know that
the chemical disrupts our hormone system? Science cannot tell us when to
begin taking action. Regulators must make a decision.

Let's look at the problem from a different angle. Suppose we find that a
commercial synthetic chemical accumulates in human fat cells. Our bodies
do not get rid of it. We do not know exactly what this alien molecule is
doing to us, but we do know that the more we are exposed to it the more
we carry around. A reasonable person would ask, "Should my body be a
waste receptacle for this substance?" When, added to that, we discover
that the substance causes illness in lab animals and interferes with
human systems, that chemical should be banned.

Fifty years ago a sensible Congress passed a precautionary law that was
easy to understand. We need a similar standard for the tens of thousands
of synthetic chemicals like BPA that have entered our world without
proper testing. First, the federal government should have the National
Academy of Sciences, a presidential panel or a similarly august group
convene scientists and charge them with reaching a consensus about how
much evidence is enough to declare, "Yes, the X group of chemicals is
dangerous." Once that is done, a screening process must be devised and
the many chemicals out there in that class should undergo the test. The
EPA could perform the screening.

Indeed, an EPA Endocrine Disruptor Screening and Testing Advisory
Committee began this kind of work in the late 1990s, but the Bush
administration showed much less interest in this area and funding dried
up. The new president and the EPA administrator who take office this
coming January could get a head start by reviewing the progress the old
committee made.

We do not have to give up plastics. Not all synthetic chemicals are
endocrine disrupt-ors. But when we find substances that are, we have to
ensure that they are kept out of our food and water.

Note: This story was originally published with the title, "Plastics in
Our Diet".

Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
PPCPs, EDCs, and Microconstituents
Mail:          P.O. Box 1105, Richmond, VA  23218 (NEW!)
Location:  629 E. Main Street, Richmond, VA  23219
PH:         804-698-4028
FAX:      804-698-4032