Perchlorate pollution: a link to thyroid disorders and possibly autism

Two recent Wall Street Journal articles raised concerns about perchlorate pollution in our country. The December 2002 article can be found at and the April 2003 article can be viewed at

These articles discuss the fact that perchlorate may have reached toxic levels in the drinking water of 20 states and contaminated the Colorado River – a river that supplies drinking water for 15 million Californians and irrigates our country’s entire winter vegetable crop.

Perchlorate is used primarily in the defense industry and, according to the articles, the U.S. government has stalled efforts to determine the full extent of the problem. A large-scale study that could have provided conclusive evidence for this problem was delayed due to lack of funding.

Perchlorate is known to affect the human thyroid gland, causing hypothyroidism. This could, in part, explain why we are seeing such a dramatic increase in thyroid problems among adults as well as children. More importantly, perchlorate has been found to affect early fetal development when women are exposed early in their pregnancy.

Studies have shown perchlorate to potentially affect speech development, behavior and attentiveness in children. In rat studies, perchlorate was also found to cause reduced head circumference at birth. Although results from rat studies are not always applicable to humans, rats have been shown to be consistently more resistant to environmental chemicals than humans. For more on this see

These findings are of particular significance in light of another California study published this year that found autistic children have a smaller head circumference at birth followed by increased head growth during the first year of life (JAMA.2003 Jul 16;290(3):337-44).

Researchers concluded that smaller head size indicates that autism is likely to be genetic and not caused by later environmental factors such as vaccines.

However, it seems to me that reduced head circumference might be caused by exposure to chemicals such as perchlorate during early fetal development. This might also cause infants to become more susceptible to environmental insults, and vaccines could be among these -particularly when they contain mercury-based preservatives.

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