A new animal study accentuates the risk of ultra-low levels of the common pesticide chlorpyrifos to cause long-lasting birth defects in female offspring of exposed mothers. The daughters exhibited learning delays, disturbed brain function and altered thyroid levels. Significantly, these symptoms resulted from low toxicity exposure during late gestation-an impact route not even part of current regulatory pesticide testing.

Damage at these doses highlights vulnerability during gestation from toxins even at the parts per billion level.

In a paper published October 29 by Reproductive Toxicology (1), a peer-reviewed academic journal, a team of researchers from the University of Wisconsin, Department of Zoology, detail their findings from research on pregnant female mice exposed to minute levels of chlorpyrifos late in gestation.

Corresponding researcher is Warren Porter, Ph.D., professor of zoology and environmental toxicology. He’s a former departmental chair, and has studied in many others fields. He was the first faculty associate at the university’s Center for Integrated Agricultural Systems with a home department outside of College of Agriculture and Life Sciences.

The results are dramatic because of the tiny doses involved, and because of the near ubiquity of chlorpyrifos present in humans. The pesticide is highly regulated because of its known hazards to human health, but is still used widely in food production, ornamental horticulture and treating buildings for insects.

Chlorpyrifos (CPF) is used in liquid termite soil treatments; as lawn/garden granules, dusts, and sprays; in household aerosols, baits, dusts, and sprays; in agricultural sprays and granules (Durban and Lorsban); and in animal flea collars, dips, and sprays. See the U.S. Environmental Protection Agency’s rap sheet on the chemical here.