I'm just posting this release verbatim, no need for an editorial.
Public release date: 21-May-2009
http://www.eurekalert.org/pub_releases/2009-05/hsop-bcu052109.php
Contact: Todd Datz
tdatz@hsph.harvard.edu
617-432-3952
Harvard School of Public Health
BPA, chemical used to make plastics, found to leach from polycarbonate
drinking bottles into humans
Exposure to BPA may have harmful health effects
Boston, MA — A new study from Harvard School of Public Health (HSPH)
researchers found that participants who drank for a week from
polycarbonate bottles, the popular, hard-plastic drinking bottles and
baby bottles, showed a two-thirds increase in their urine of the
chemical bisphenol A (BPA). Exposure to BPA, used in the manufacture of
polycarbonate and other plastics, has been shown to interfere with
reproductive development in animals and has been linked with
cardiovascular disease and diabetes in humans. The study is the first to
show that drinking from polycarbonate bottles increased the level of
urinary BPA, and thus suggests that drinking containers made with BPA
release the chemical into the liquid that people drink in sufficient
amounts to increase the level of BPA excreted in human urine.
The study appears on the website of the journal Environmental Health
Perspectives and is freely available at
http://www.ehponline.org/members/2009/0900604/0900604.pdf.
In addition to polycarbonate bottles, which are refillable and a popular
container among students, campers and others and are also used as baby
bottles, BPA is also found in dentistry composites and sealants and in
the lining of aluminum food and beverage cans. (In bottles,
polycarbonate can be identified by the recycling number 7.) Numerous
studies have shown that it acts as an endocrine-disruptor in animals,
including early onset of sexual maturation, altered development and
tissue organization of the mammary gland and decreased sperm production
in offspring. It may be most harmful in the stages of early development.
"We found that drinking cold liquids from polycarbonate bottles for just
one week increased urinary BPA levels by more than two-thirds. If you
heat those bottles, as is the case with baby bottles, we would expect
the levels to be considerably higher. This would be of concern since
infants may be particularly susceptible to BPA's endocrine-disrupting
potential," said Karin B. Michels, associate professor of epidemiology
at HSPH and Harvard Medical School and senior author of the study.
The researchers, led by first author Janeny Carwile, a doctoral student
in the department of epidemiology at HSPH, and Michels, recruited
Harvard College students for the study in April 2008. The 77
participants began the study with a seven-day"washout" phase in which
they drank all cold beverages from stainless steel bottles in order to
minimize BPA exposure. Participants provided urine samples during the
washout period. They were then given two polycarbonate bottles and asked
to drink all cold beverages from the bottles during the next week; urine
samples were also provided during that time.
The results showed that the participants' urinary BPA concentrations
increased 69% after drinking from the polycarbonate bottles. (The study
authors noted that BPA concentrations in the college population were
similar to those reported for the U.S. general population.) Previous
studies had found that BPA could leach from polycarbonate bottles into
their contents; this study is the first to show a corresponding increase
in urinary BPA concentrations in humans.
One of the study's strengths, the authors note, is that the students
drank from the bottles in a normal use setting. Additionally, the
students did not wash their bottles in dishwashers nor put hot liquids
in them; heating has been shown to increase the leaching of BPA from
polycarbonate, so BPA levels might have been higher had students drunk
hot liquids from the bottles.
Canada banned the use of BPA in polycarbonate baby bottles in 2008 and
some polycarbonate bottle manufacturers have voluntarily eliminated BPA
from their products. With increasing evidence of the potential harmful
effects of BPA in humans, the authors believe further research is needed
on the effect of BPA on infants and on reproductive disorders and on
breast cancer in adults.
"This study is coming at an important time because many states are
deciding whether to ban the use of BPA in baby bottles and sippy cups.
While previous studies have demonstrated that BPA is linked to adverse
health effects, this study fills in a missing piece of the
puzzle—whether or not polycarbonate plastic bottles are an important
contributor to the amount of BPA in the body," said Carwile.
###
The study was supported by the Harvard University Center for the
Environment and the National Institute of Environmental Health Sciences
Biological Analysis Core, Department of Environmental Health, HSPH.
Carwile was also supported by the Training Program in Environmental
Epidemiology.
"Use of Polycarbonate Bottles and Urinary Bisphenol A Concentrations,"
Jenny L. Carwile, Henry T. Luu, Laura S. Bassett, Daniel A. Driscoll,
Caterina Yuan, Janenifer Y. Chang, Xiaoyun Ye, Antonia M. Calafat, Karin
B. Michels, Environmental Health Perspectives, online May 12, 2009.