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BPA is used in many common plastics. |
Environmental exposure to a widespread compound used to make common
plastic food containers and baby bottles and to line tin cans interferes
with cell division in the eggs of female mice, according to research.
If cell division is disturbed, it can result in aneuploidy, or
an abnormal number of chromosomes in the eggs. This condition is
the leading cause of mental retardation and birth defects in humans,
including Down syndrome.
Even extremely low levels of the compound, called Bisphenol A (BPA),
produced genetic abnormalities, according to researchers. BPA exhibits
hormone-like properties and imitates the effects of naturally occurring
estrogens.
Researchers began to study BPA after normal mice began to display
genetic abnormalities that are typically uncommon. The defects were
linked to plastic cages and water bottles that had been cleaned
with a harsh detergent, causing BPA to leak from the plastic.
Researchers then determined how much BPA the mice had been exposed
to and how small a dose would produce effects. An extremely small
dose of 20 parts/billion daily for five to seven days was enough
to produce effects.
Researchers are uncertain of the effect of BPA on humans, however
they noted that mice and humans have a very similar cell division
program for eggs.
Previous studies have suggested that exposing animals in the womb
to levels of BPA similar to those found in the environment disrupts
their sperm count, prostate and testicular development. However,
other studies, some funded by the plastics industry, have not found
any risks associated with BPA exposure.
Some experts say that, taken together, study results suggest that
efforts to begin reducing human exposure to BPA are warranted.
Current
Biology April 2003;13:546-553
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