Questions and Answers

Perchlorate and Health: Part 1


Q: What has been learned about perchlorate in the past few years?

PERCHLORATE HAS NO MEASURABLE EFFECT ON HUMAN HEALTH BELOW LEVELS OF 245 PPB, AND ACCORDING TO SOME RESEARCH, IT TAKES AT LEAST 100 TIMES THIS AMOUNT TO HAVE ANY ADVERSE HEALTH EFFECT.

A: A great deal is known about perchlorate, in part because of its longstanding use as a medicine. Substantial research has been conducted since the mid-1990s to improve scientific and medical understanding of perchlorate's health effects. These studies, particularly one by Greer, et al. show there are no measurable effects on human beings at levels many times higher than the minute amounts being found in some drinking water supplies.

 

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Q: How does perchlorate affect human health?

A: Credible studies show perchlorate's direct effects on human health are limited to the thyroid. High levels of perchlorate can prevent the thyroid gland from absorbing iodide (which it needs to make hormones) from the bloodstream. This in itself is not dangerous however, because the body automatically compensates for this.

 

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Q: What does it take to cause an adverse health effect?

A: A sequence of three events is required for perchlorate to have any adverse effect on health, each requiring higher doses of perchlorate. According to a study by Dr. Steven H. Lamm, it takes at least 100 times this amount (or 20,000 ppb) to have any adverse health effect. For the body to experience adverse health effects, the three events that must occur are:

First: Perchlorate exposure must be high enough to prevent the thyroid from getting its usual amount of iodide. This may begin to happen at around 245 ppb of perchlorate in drinking water, AND.

Second: Exposure must be high enough to overwhelm the body's normal adaptive process, thereby lowering the amount of thyroid hormones in the body (scientific research indicates this does not occur at levels below 14,000 ppb), AND.

Third: Exposure must be high enough, and sustained long enough, to reduce thyroid hormone levels for a long period of time. An adverse health effect would require daily consumption of more than 14,000 ppb in drinking water. This would require an adult to drink 500 gallons of water per day with 20 ppb perchlorate.

 

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Q: Does perchlorate stay in the body?

A: Perchlorate is not stored anywhere in the body.

 

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Q: Why isn't it an adverse health effect when perchlorate inhibits the thyroid gland's ability to absorb iodide?

A: "Inhibition of iodide uptake," as this effect is called, is a routine occurrence, caused by a number of factors in our diet and environment. The body naturally compensates if the thyroid can't absorb its normal amount of iodide from the bloodstream. The thyroid itself has an enormous iodide reserve. It also can open additional "channels" to let more iodide in. It's important to note that most Americans eat a diet that provides more than twice the daily need of iodide.

 

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Q: Are the effects of perchlorate on the body permanent?

A: Although there are no measurable effects when perchlorate is in the body at low levels, any effects of perchlorate on the body's ability to produce hormones are fully reversible once exposure to high levels declines or stops.

 

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