Health-Protective Drinking Water Level for Perchlorate

Sample size: 37 publication 10 minutes Evidence: moderate

Author Information

Author(s): Ting David Howd, Robert A. Fan, Anna M. Alexeeff, George V.

Primary Institution: Office of Environmental Health Hazard Assessment, California Environmental Protection Agency

Hypothesis

Can a health-protective drinking water level for perchlorate be established based on its effects on thyroidal iodide uptake?

Conclusion

A health-protective drinking water level of 6 ppb for perchlorate was determined to adequately protect sensitive populations, including pregnant women and their fetuses.

Supporting Evidence

Perchlorate exposure can reduce thyroidal iodide uptake, which is critical for hormone production.
The calculated health-protective level of 6 ppb is based on a benchmark dose modeling approach.
Sensitive populations, including pregnant women, are at higher risk from perchlorate exposure.
Animal studies show that perchlorate can induce thyroid tumors at high doses, but it is not believed to pose a significant cancer risk to humans.
Human studies indicate that perchlorate can cause a decrease in thyroidal iodide uptake without significant changes in serum thyroid hormone levels.

Takeaway

This study found that perchlorate can reduce the amount of iodine the thyroid takes in, which is important for health, especially for pregnant women and babies. They suggest a safe level of perchlorate in drinking water.

Methodology

The study evaluated animal and human toxicity data for perchlorate and applied benchmark-dose modeling to human data to determine a point of departure for risk assessment.