FDA changes course, says it has concerns about BPA
BPA poseur unmasked by investigative journalists
Congress digs for BPA lobbyists' documents
Losing on science, BPA lobbyists planning to play 'fear card'
BPA timeline by Fred vom Saal
Controversy swirls around industry paper used by FDA to reach safety decision
Flawed analysis of BPA safety commits many errors
New CDC data confirms ubiquitous exposure to BPA at significant levels
BPA causes uterine fibroids and polycystic ovaries in mice
Consensus statement on risks of BPA by leading experts raises significant concerns
BPA scrambles the chromosomes of grandchildren in mice
BPA interferes with treatment for prostate cancer
BPA causes breast cancer in rats
BPA increases sensitivity to carcinogen causing breast cancer in rats
Low-level BPA tied to prostate cancer
Flaws and misrepresentations in science used to by industry to assert bisphenol A safety
Industry mounts coalition to defeat California legislature on bisphenol A
Low-level BPA causes insulin resistance in mice
BPA tied to recurrent miscarriage in people
Low level BPA adversely affects prostate development
Industry criticisms of BPA science flawed
Scientists call for new risk assessment of BPA and reveal industry bias in research
BPA is as powerful as estradiol at initiating calcium influx into cells
Link to detailed summary of a discovery that links bisphenol A to the mechanism that causes birth defects and spontaneous miscarriage in people, plus press coverage
See below for more recent studies
Latest news about bisphenol A
More news about
Another compound invented during that era, diethylstilbestrol, turned out to be more powerful as an estrogen, so bisphenol A was shelved... until polymer chemists discovered that it could be polymerized to form polycarbonate plastic. Unfortunately, the ester bond that links BPA monomers to one another to form a polymer is not stable and hence the polymer decays with time, releasing BPA into materials with which it comes into contact, for example food or water.
Bisphenol A is now deeply imbedded in the products of modern consumer society, not just as the building block for polycarbonate plastic (from which it then leaches as the plastic ages) but also in the manufacture of epoxy resins and other plastics, including polysulfone, alkylphenolic, polyalylate, polyester-styrene, and certain polyester resins.
uses don't end with the making of plastic. Bisphenol A has been
used as an inert ingredient in pesticides (although in the US this
has apparently been halted), as a fungicide, antioxidant, flame
retardant, rubber chemical, and polyvinyl chloride stabilizer.
uses create a myriad of exposures for people. Bisphenol A-based
polycarbonate is used as a plastic coating for children's teeth
to prevent cavities, as a coating in metal cans to prevent the metal
from contact with food contents, as the plastic in food containers,
refrigerator shelving, baby bottles, water bottles, returnable containers
for juice, milk and water, micro-wave ovenware and eating utensils.
exposures result from BPA's use in "films, sheets, and laminations;
reinforced pipes; floorings; watermain filters; enamels and vanishes;
adhesives; artificial teeth; nail polish; compact discs; electric
insulators; and as parts of automobiles, certain machines, tools,
electrical appliances, and office automation
instruments" (Takahashi and
contamination is also widespread in the environment. For example,
BPA can be measured in rivers and estuaries at concentrations that
range from under 5 to over 1900 nanograms/liter. Sediment loading
can also be significant, with levels ranging from under 5 to over
100 µg/kg (ppb) BPA is quite persistent as under normal conditions
in the environment it does not readily degrade (Rippen
this all means is that most of your life you are within arm's length
or closer to bisphenol A. No wonder the
debate over its toxicity is so intense.
important recent studies of bisphenol A:
Experiments with rats demonstrate that low level exposure to bisphenol A during fetal growth causes breast cancer in adults. At all levels tested down to 2.5 parts per billion, BPA induced formation of aberrant cell growth patterns associated in rodents and people with breast cancer. Levels only 5 times higher than EPA's current safe level caused carcinoma in situ. Using these results to set safety standards would radically reduce use of BPA in plastics and resins. More...
In utero exposure to BPA causes long-term effects on mammary tissue development in rats, increasing risks to cancer, and also increases sensitivity to a chemical known to cause breast cancer. The study strengthens support for a link between increasing rates of breast cancer in recent decades and increasing exposure to estrogenic chemicals like BPA. It also indicates that human epidemiological studies that fail to incorporate developmental exposures can't be trusted to identify cancer-causing agents. More...
Perinatal exposure to extremely low levels of bisphenol A causes precancerous prostate lesions in rats. These lesions, called prostatic intraepithelial neoplasia, or PIN, are cancerous and are considered to be a precursor of metastatic prostate cancer in humans. One hundred percent of rats exposed perinatally and then, during adulthood, treated with estradiol and testosterone to create hormonal conditions analogous to thos of an ageing man, developed high-grade PIN. The effect appears to result from the failure in exposed animals of a gene to become hypermethylated as the rats aged. More...
Experiments with mice reveal that chronic adult exposure to bisphenol A causes insulin resistance. Insulin resistance in people leads to Type II diabetes and congestive heart failure, and is part of the modern epidemic of 'metabolic syndrome.' The exposure levels used were within the range that people experience regularly. More...
In a small prospective study, researchers in Japan report that bisphenol A levels are higher in women with a history of repeated spontaneous miscarriages. This research was based on proof that BPA causes meiotic aneuploidy in mice. Meiotic aneuploidy is the commonest cause of miscarriage in people. The researchers also followed the pregnancies of the women to completion, and found evidence of aneuploidy in several of the miscarried fetuses. More...
Bisphenol A and the birth control pharmaceutical ethinylestradiol cause adverse effects in prostate development in mice at levels to which millions of Americans are exposed each year. The results implicate these compounds in human prostate diseases, including prostate cancer. The research also shows the futility of predicting the developmental consequences of low-dose exposures based on high-dose experiments. More...
A flood of new information about bisphenol A revealing both widespread human exposure and effects at extremely low doses sparks a call for a new risk assessment of the ubiquitous compound. Bisphenol A, the basic building block of polycarbonate plastic, alters development of the reproductive tract, the immune system, increases prostate tumor proliferation, changes brain chemistry and structure and affects an array of behaviors, including hyperactivity. Of 11 studies of the compound's effects at low doses, none funded by industry reported impacts. In contrast, 94 out of 104 government-funded studies found effects. This summary includes audio files of an international teleconference about bisphenol A. More...
Several 'weakly' estrogenic compounds including bisphenol A and endosulfan are as powerful as estrogen at increasing calcium influx into cells and stimulating prolactin secretion. The effects are mediated by a cell membrane surface receptor instead of nuclear hormone receptors, the focus of most studies to date. Changes in calcium and prolactin occur at extremely low doses, well within the range of human exposures. Wozniak, AL, NN Bulayeva and CS Watson. 2005. Xenoestrogens at Picomolar to Nanomolar Concentrations Trigger Membrane Estrogen Receptor-alpha-Mediated Ca++ Fluxes and Prolactin Release in GH3/B6 Pituitary Tumor Cells. Environmental Health Perspectives, in press.
Bisphenol A at extremely low levels causes changes in brain structure and behavior in rats. The locus coeruleus is believed to be a key brain center for anxiety and fear. Normally this is larger in females than in males. Rats exposed to BPA at levels beneath the current 'safe' exposure level established by the US EPA show a reversal in sex dimorphism, with males' LC larger than females.' . Kubo, K, O Arai, M Omura, R Wantanabe, R Ogata, and S Aou. 2003. Low dose effects of bisphenol A on sexual differentiation of the brain and behavior in rats. Neuroscience Research 45: 345-356.
Exposures to 1/5th the level considered safe are sufficient to alter maternal behavior in mice, including reductions in time spent nursing, increases in time resting away from offspring, and increases in time spent out of the nest. Palanza, P, KL Howdeshell, S Parmigiani and FS vom Saal. 2002. Exposure to a low dose of bisphenol A during fetal life or in adulthood alters maternal behavior in mice. Environmental Health Perspectives 110 (suppl 3): 415-422.
accident in the lab, followed by careful analysis and a series of
experiments, reveals that bisphenol A causes aneuploidy
in mice at low levels of exposure. Because aneuploidy in
humans causes spontaneous miscarriages and some 10-20% of all birth
defects, including Down Syndrome, this implicates bisphenol A in
a broad range of human developmental errors. Hunt,
PA, KE Koehler, M Susiarjo, CA Hodges, A Ilagan, RC Voigt, S Thomas,
BF Thomas and TJ Hassold. 2003. Bisphenol
A exposure causes meiotic aneuploidy in the female mouse.
Current Biology 13: 546-553.
by researchers at the University of Missouri raise the possibility
of widespread contamination of laboratory experiments by
bisphenol A. Their results demonstrate that at room temperature
significant amounts of this estrogenic substance leach into water
from old polycarbonate animal cages. This
inadvertent contamination could interfere with experiments
designed to test the safety of estrogenic chemicals, and
lead to false negatives and conflicting results.
Howdeshell, KA, PH Peterman, BM Judy, JA Taylor,
CE Orazio, RL Ruhlen, FS vom Saal, and WV Welshons 2003. Bisphenol
A is released from used polycarbonate animal cages into water at
room temperature. Environmental Health Perspectives
analysis of the biochemical mechanisms of endocrine disruption suggests
why industry has been unable to replicate crucial low-dose impacts
of bisphenol A on prostate development.
WV, KA Thayer, BM Judy, JA Taylor, EM Curran and FS vom Saal. 2003.
Large effects from
small exposures. I. Mechanisms for endocrine disrupting chemicals
with estrogenic activity. Environmental Health
new analytical methods, a team of German scientists measured bisphenol
A in the blood of pregnant women, in umbilical blood at birth and
in placental tissue. All samples examined contained BPA,
at levels within the range shown to alter development. Thus
widespread exposure to BPA at levels of concern is no longer a hypothetical
issue. It is occurring. Schönfelder,
G, W Wittfoht, H Hopp, CE Talsness, M Paul and I Chahoud. 2002.
Bisphenol A Accumulation in the Human Maternal-Fetal-Placental Unit.
Environmental Health Perspectives 110:A703-A707.
extremely low levels, BPA promotes fat cell (adipocyte) differentiation
and accumulation of lipids in a cell
culture line used as a model for adipocyte formation. These two
steps, differentiation and accumulation, are crucial in the development
of human obesity. Hence this result opens up a whole new chapter
in efforts to understand the origins of the world-wide obesity epidemic.
Masuno, H, T Kidani, K Sekiya, K Sakayama, T Shiosaka, H Yamamoto
and K Honda. 2002. Bisphenol
A in combination with insulin can accelerate the conversion of 3T3-L1
fibroblasts to adipocytes. Journal of Lipid Research
cell culture experiments, BPA at very low (nanomolar levels)
stimulates androgen-independent proliferation of prostate cancer
cells. This finding is especially important because when
prostate tumors become androgen-independent they no longer respond
to one of the key therapies for prostate cancer. Wetherill,
YB, CE Petre, KR Monk, A Puga, and KE Knudsen. 2002. The
Xenoestrogen Bisphenol A Induces Inappropriate Androgen Receptor
Activation and Mitogenesis in Prostatic Adenocarcinoma Cells.
Molecular Cancer Therapeutics 1: 515–524.
causes changes in rat ventral prostate cells that appear similar
to events that make nascent prostate tumors in humans more
potent: Ramos, JG, J Varayoud,
C Sonnenschein, AM Soto, M Muñoz de Toro and EH Luque. 2001.
Exposure to Low Doses of Bisphenol A Alters the Periductal Stroma
and Glandular Cell Function in the Rat Ventral Prostate.
Biology of Reproduction 65: 12711277.
induces changes in mouse mammary tissue that resemble early stages
mouse and human of breast cancer: Markey,
CM, EH Luque, M Muñoz de Toro, C Sonnenschein and AM Soto.
2001. In Utero
Exposure to Bisphenol A Alters the Development and Tissue Organization
of the Mouse Mammary Gland. Biology of Reproduction
lowers sperm count in adult rats even at extremely low levels:
M, S Ohsako, R Ishimura, S Kurosawa, M Kurohmaru, Y Hayashi, Y Aoki,
J Yonemoto and C Tohyama. 2001. Bisphenol-A
Affects Spermatogenesis in the Adult Rat Even at a Low Dose.
Journal of Occupational Health 43:185 -190.
at extremely low levels creates superfemale snails.
Oehlmann, J, U Schulte-Oehlmann, M Tillmann and B Markert. 2000.
of endocrine disruptors on Prosobranch snails (Mollusca: Gastropoda)
in the laboratory. Part I: Bisphenol A and Octylphenol as xenoestrogens.
is rapidly transfered to the fetus after maternal uptake:
O and S Oishi. 2000. Disposition
of Orally Administered 2,2-Bis(4-hydroxyphenyl) propane (Bisphenol
A) in Pregnant Rats and the Placental Transfer to Fetuses.
Environmental Health Perspectives 108:931-935.
independently funded, academic laboratory can verify controversial
BPA results, even though industry can't: Gupta,
Chhanda. 2000. Reproductive malformation
of the male offspring following maternal exposure to estrogenic
chemicals. Proceedings of the Society for Experimental
Biology and Medicine 224:61-68.
differences between rats and humans probably mean that humans
are more sensitive to BPA than are rats: Elsby,
R, JL Maggs, J Ashby and BK Park. 2001. Comparison
of the modulatory effects of human and rat liver microsomal metabolism
on the estrogenicity of bisphenol A: implications for extrapolation
to humans. Journal of Pharmacology and Experimental Therapeutics
confirmation of BPA low dose effects, and demonstration that
the effects include impacts on estrous cyclicity and plasma LH levels:
Rubin, BS, MK Murray, DA Damassa, JC King and AM Soto. 2001. Perinatal
Exposure to Low Doses of Bisphenol A Affects Body Weight, Patterns
of Estrous Cyclicity, and Plasma LH Levels. Environmental
Health Perspectives 109: 675-680.
speeds the pace of sexual development in mice, and causes
mice to be obese: Howdeshell,
K, AK Hotchkiss, KA Thayer, JG Vandenbergh and FS vom Saal. 1999.
A speeds growth and puberty. Nature 401: 762-764.