Plastic Linked to Birth
Bisphenol-A (BPA), the primary component of polycarbonate plastic bottles, has recently been proven to leach from the plastic and to be a cause of miscarriages and birth defects. A study published in April 2003, showed that very small amounts of BPA caused female mice to produce eggs with abnormal numbers of chromosomes, a condition called aneuploidy. Aneuploidy is the leading cause of miscarriages and several forms of mental retardation in humans, including Down’s syndrome. The finding raises serious questions about the safety of BPA. BPA polycarbonate plastic is used to make pop, juice and water bottles. It is also a major ingredient in a wide range of other products, from baby bottles to tooth protecting sealants. Bisphenol-A is an estrogen mimic and has now also been shown to cause genetic mutations.
The finding came as an accident. Scientists were trying to find the cause of a major problem in human reproduction. They were looking for the reason that up to 25% of fertilized human eggs have an abnormal number of chromosomes. When the scientists found wildly fluctuating rates of aneuploidy in their mice, they tracked the cause to the mice cages which had been washed in a harsh detergent. They found that the cages were made of polycarbonate, which released BPA when damaged by the detergent. The team recreated the accidental BPA exposure by housing some mice in newly damaged polycarbonate cages and others in BPA free cages. Aneuploidy rates skyrocketed in mice exposed to the BPA laden plastic compared with those of the control mice, the team reports in the April issue of Current Biology. In another experiment, the group provided mice with BPA laced drinking water at concentrations matching those of the accidental BPA exposures. The more BPA the animals ingested, the higher the aneuploidy incidence.
“BPA pervades the environment at the concentrations that spurred aneuploidy in mice,” says Patricia Hunt, the reproductive biologist at Case Western University who led the study. “It’s kind of scary.”
Earlier studies had failed to link environmental factors, including smoking and alcohol, to chromosomal defects in egg cells, notes cyto (cell) geneticist Dorothy Warburton of Columbia University. She says the new study “shows that there are things in the environment that can affect aneuploidy.”
Commenting on the study, Dr. Gerald Ross, former director of the Environmental Medicine Centre in Halifax said, “The findings of this study have enormous importance. Environmental medicine physicians have been saying for years that putting food and drink into plastic containers was fraught with hazard. The newer clear transparent plastic polycarbonate bottles, which are used to package spring water, juice and soda and other products, release the chemical Bisphenol-A into the liquids that the bottle contains. In addition to being an estrogen mimic, that chemical has now been clearly shown to cause genetic mutations.”
This is not the first time chemicals from plastics have been found to create human health risks. Phthalates, chemicals which can cause birth defects in the male reproductive system, are known to leach out of PVC plastic products. In January 2000, Health Canada recommended restricting use of medical devices containing the phthalate DEHP. In 1998, children’s teethers and rattles made of phthalate containing PVC plastic were withdrawn after a Health Canada advisory.
(BPA) info from Science
News, April, 2003)