1 April 2003
spoil mouse eggs
compound affects reproductive cell division.
chemical commonly found in plastic food containers harms growing
mouse eggs, according to a new study1 - fuelling the debate over
the additive's safety.
compound is called bisphenol A (BPA). It is widely used in see-through
bottles and for lining tin cans. Its chemical activity mimics that
of the female hormone oestrogen, so some fear that it might damage
an unborn baby's growing sex organs.
the latest study, Patricia Hunt of Case Western Reserve University
in Cleveland, Ohio discovered unusual genetic defects in the eggs
of her laboratory mice. She traced it to their hard plastic cages,
which were leaching BPA.
traces - 20 parts per billion in drinking water - altered 8% of
eggs, her team found. Normally, only 1% of eggs are defective. Humans
are exposed to similar BPA levels, Hunt says, although it is not
known if they have the same effect.
theory, such genetic flaws could cause a higher incidence of miscarriage
or of conditions such as Down's syndrome. "You're talking about
transmitting profound chromosomal damage to your baby," says
PBA researcher Frederick vom Saal of the University of Missouri-Columbia.
Hentges of the American Plastics Council in Arlington, Virginia,
counters that it is too early to condemn BPA - because the team
have yet to show whether the genetic changes actually affect the
mice's ability to reproduce. "We don't know how to interpret
this yet," he argues.
investigations hinted that exposing animals in the womb to levels
of BPA similar to those found in the environment upsets their sperm
count, prostate and testicular development. Other studies - some
commissioned by the plastics industry - have found BPA to be completely
don't have any reason to believe there's any effect
US Food and Drugs Administration
has gone a step further in showing that BPA might also harm an egg's
DNA; this damage might be inherited by offspring formed from those
eggs. She finds that BPA stops chromosomes from dividing up equally
before egg cells divide, possibly by interfering with oestrogen's
vom Saal and others would like to see BPA regulations tightened.
Some regulatory bodies are already reviewing the allowable levels:
a European Commission's food-safety committee, for example, last
year slashed its upper limit for daily intake fivefold.
US Food and Drug Administration does not have a safety limit for
BPA on foodstuffs. "We don't have any reason to believe there's
any effect," argues the administration's George Pauli, who
is involved in regulating the safety of plastics in food packaging.
But the agency keeps tabs on new research, he adds.
Hunt, P.A. et al. Bisphenol A exposure causes meiotic aneuploidy
in the female mouse. Current Biology, 13, 546 - 553, (2003).