31 March 2003
links common plastic to birth defects
(Reuters) - A common ingredient used to make plastics such as baby
bottles causes birth defects in mice -- defects that could also
occur in people, U.S. researchers said on Monday.
urged more research into the potential effects of bisphenol A, a
chemical long criticized by environmentalists as being a hormone
disruptor that could cause defects in embryos.
defects they found, when they occur in humans, can cause miscarriages
or mental retardation such as Down Syndrome -- and they seem to
be caused at what were considered to be low levels of exposure,
the researchers report in the journal Current Biology.
discovery came by accident, Patricia Hunt and colleagues at Case
Western Reserve University in Ohio report.
team first noted a higher than normal increase in abnormalities
in developing egg cells in female mice.
were looking at the processes as cells start to undergo division,"
Hunt, a geneticist, said in a telephone interview.
chromosomes are supposed to line up in an orderly fashion so they
can divide in an orderly fashion. What we saw was a tremendous increase
in the number of cells in which the alignment of chromosomes in
the cells were not orderly at all -- they were very disorderly."
the mice they were studying this only usually happens 2 percent
of the time, but Hunt's team said 40 percent of the eggs were developing
spent weeks looking for the cause.
turned up. But...I noticed that the plastic cages looked kind of
the worst for wear," Hunt said.
turned out that a harsh detergent used to clean the cages had broken
down the plastic, releasing bisphenol A.
team deliberately exposed mice to small amounts of bisphenol A for
short periods of time and found the abnormalities increased again.
THAT DISRUPT HORMONES
labs are studying the effects of bisphenol A and other chemicals
that act as endocrine disruptors -- affecting the actions of hormones
in the body. Some scientists fear that developing fetuses and young
children are especially vulnerable to these effects.
Hunt hasn't shown damage in fetuses yet, but it has to be a subject
of concern," said Fred vom Saal, an expert on the effects of
toxins on reproduction at the University of Missouri.
A is one of the most commonly used plastic materials in food containers,
in beverage containers. This is a ubiquitous chemical...at least
in the developed world. It is one of the top 50 chemicals in production."
who studies the effects of aging on egg cells and fertility, said
she was not even looking for chemical influences. "That's one
of the things I think makes our study unusual," she said.
the study says nothing about the effects of bisphenol A in humans,
Hunt said there is reason to believe they would be similar. The
changes in the mice cause aneuploidy -- a misalignment of the chromosomes
that is seen in human birth defects and miscarriages.
don't wait to prove that it does that in people before you take
some regulatory action," Vom Saal said, adding that he hopes
Congress may now agree to fund more studies on the effects of bisphenol
are talking about these mice essentially drinking out of old baby
bottles," Vom Saal said -- noting that hard plastic containers
like bottles start leaching bisphenol A when they begin to look
cracked or etched.
urged the chemical industry to make more plastic products that do
not contain bisphenol A.
of the funding for the study came from the industry-supported American
Chemistry Council via the National Institute for Environmental Health