Air Date: Week of April 4, 2003

Living on Earth’s Jennifer Chu reports on a lab accident that proved to be a valuable clue in the study of chromosome mutations.

Transcript

CURWOOD: Coming up, the SARS outbreak threatens the health of the economy as well as the health of people. First, this Note on Emerging Science from Jennifer Chu.

[MUSIC: Science Note Theme]

CHU: Discoveries in the lab are usually the result of months of carefully designed, meticulously controlled experiments. But a recent discovery at Case Western Reserve University was actually the result of a lab accident. Researchers had been studying the causes of chromosome mutations in rats. These mutations happen when too many or too few chromosomes are created during cell division. In humans, these abnormalities have been shown to cause spontaneous miscarriages and birth defects, including Down Syndrome.

In this experiment, scientists were stumped by a sudden eightfold spike in chromosome abnormalities, in what was supposed to be the normal control group of rats. The researchers eventually discovered that a worker had used a harsh alkaline detergent to wipe down the rats' plastic cages. This caused the cage bars to deteriorate and release a chemical in the plastics called bisphenol-a or BPA. The detergent also corroded the spray bottle, which in turn leeched BPA into the water, exposing the rats to even more of the chemical. Researchers thought this might be a clue as to why the normal rats had so many chromosome abnormalities. To find out, they exposed rats to low levels of BPA, and sure enough, that caused similar abnormalities confirming that the contaminant was the culprit in the chromosome mutation spike.

BPA is a chemical used to manufacture some types of plastics. It can be found in plastic resins, flame retardants, nail polish and adhesives, to name just a few uses. The researchers have not studied BPA's effect on human health, but say that mutations caused by such a brief exposure to the chemical are a cause for concern and further study.

That's this week's Note on Emerging Science. I'm Jennifer Chu.

CURWOOD: And you're listening to Living on Earth.

[MUSIC: Stella Rambisai Chiweshe “Chigamba” The Pulse of Life - Ellipsis Arts (1991)]