Rethinking Healthcare

BPA strikes again, causing sterility and killing embryos (in worms)

BPA strikes again, causing sterility and killing embryos (in worms)

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Exposure to bisphenol A, a chemical found in thousands of everyday products, causes chromosome abnormalities that sterilize worms and kill off their embryos.

By disrupting chromosomes, bisphenol A (BPA) is sterilizing worms in the lab and killing off their embryos – the latest in the BPA fear saga.

The controversial and ubiquitous chemical, found in plastics like baby bottles and lines the packaging for much of our food and beverages, has already been linked to heart disease, some cancers, and miscarriages.

The National Toxicology Program concluded in 2008 that there was at most “some concern” that BPA was toxic to fetuses and infants. But a Proceedings of the National Academy of Sciences study revealed yesterday that roundworms exposed to BPA showed a sixfold reduction in the average number of eggs laid and a 97% increase in embryonic death.

Harvard Medical School researchers Patrick Allard and Monica Colaiacovo dosed strains of roundworm with various concentrations of BPA. They discovered damages to certain processes that repair DNA in the sex cells that later go on to develop into sperm and eggs.

Without that DNA repair and maintenance work, the resulting chromosome abnormalities (image) ultimately lead to embryo death and fewer eggs.

The roundworm Caenorhabditis elegans has recently emerged as a model organism for biomedical studies on toxicology, one that is both cheaper and quicker than mice. According to the authors, “the prompt assessments” made by using worms will better focus follow-up studies on BPA in mammals.

The plastic constituent was respotlighted last month when Canada formally declared the chemical to be toxic, despite strenuous protest by the chemical industry. Then two weeks later, BPA was tied to low sperm quality in Chinese factory workers. Earlier this month, BPA research delivered a one-two punch: one study found that it’s readily absorbed through the skin, while a second showed how people who routinely touch BPA-laden receipts (such as cashiers) have higher levels of it in their bodies.

Human exposure to BPA remains widespread; about 4 metric tons are produced globally a year. A 2004 survey conducted by the Centers for Disease Control and Prevention (CDC) found detectable levels of BPA in 93% of 2517 urine samples from people six years and older. Several states have since banned the chemical in children’s products, and Nalgene, for example, has been transitioning to BPA-free materials over the last couple years. Taken together, these studies continue to confirm a consumer fear that has been driving retailers to limit or remove BPA from their products.

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Janet Fang

Contributing Editor

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York. Follow her on Twitter. Disclosure