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Last Edited: 9/5/2008

Perchlorate in Drinking Water and Newborn Thyroid Function

Historic waste disposal practices at the Aerojet-General Corporation facility in Rancho Cordova contaminated some of that city's underground drinking water supply with perchlorate, starting in the late 1980s. Since February 1997, these wells have not been used to supply drinking or household water (click to view the April 1998 Health Consultation on Perchlorate contamination).

Perchlorate is an ionic compound (a salt) that, when consumed, can suppress the production of thyroid hormones. Thyroid hormones are important for regular metabolism in adults. More importantly, thyroid hormones are essential to the development of the nervous and skeletal systems in the fetus and infant. Studies in animals and humans have shown that in utero exposure to high levels of perchlorate can suppress thyroid hormone production and thereby interfere with the development of the nervous and skeletal systems of a fetus. One unanswered question is whether maternal exposure to lower levels of perchlorate, such as that which occurred in Rancho Cordova, can affect thyroid hormones of the fetus.

The “Maternal Exposure to Perchlorate in Drinking Water and Newborn Thyroid Function” health study is designed to investigate whether in utero exposure to perchlorate is associated with lower levels of thyroid hormone in newborns born to mothers who resided in Rancho Cordova during the years that the city’s water was contaminated with perchlorate. The study will also examine the association between perchlorate exposure and a pituitary hormone linked to thyroid function (thyroid stimulating hormone), as well as birth weight.

Results, a final report, and information materials are scheduled to be available in early 2007.

This study is being conducted in partnership with the Newborn Screening Program of the Genetic Disease Branch and with the University of California at Davis, Department of Land, Air and Water Resources.



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