The Council on Water Quality today expressed concern that Congress and the public could be misled by several recent, inaccurate public characterizations of the science related to the health effects of perchlorate. The National Academy of Science (NAS) report on perchlorate, issued in 2005, remains the authoritative scientific document on perchlorate and human health.
Special interest groups have erroneously characterized the findings of a recent FDA report, claiming that it concluded that perchlorate exposure from food, combined with exposure from water, exceeds safe levels. The facts clearly demonstrate otherwise.
The apparent confusion relates to what the FDA findings might mean in the context of a perchlorate “reference dose” (RfD). A reference dose is the amount of a substance determined by regulatory
agencies to be safe for anyone, regardless of age, to consume daily over a lifetime.
To establish the state of the science regarding perchlorate and human health, a special panel of the National Academy of Sciences conducted a thorough review of five decades of research. The NAS panel concluded that perchlorate levels below 245 parts per billion (ppb) had no observable health effect. The panel further stated any health effects at that level were not adverse. Nonetheless, to ensure a margin of safety for vulnerable subpopulations, including pregnant and nursing mothers, infants and young children, the NAS applied a ten-fold safety factor to the “no effect level,” and suggested an extremely protective RfD of 24.5 ppb.
The manner in which the NAS panel set that reference dose and its high level of protection should not be overlooked. Further, no new credible, peer-reviewed studies have been published since the NAS findings which suggest perchlorate levels below 245 ppb cause adverse health effects. This includes the FDA study and the oft quoted ‘Blount study,’ which has also been misrepresented by some interest groups.
Statements that anyone, including children, might be exposed to unsafe levels because of perchlorate from food are inconsistent with the science and simply incorrect. It’s doubtful anyone’s intake exceeds the reference dose, but even if it did, exposure above 24.5 ppb must be considered in the context of a non-adverse effect.
U.S. EPA recently collected 34,193 water samples from public water systems. Perchlorate was detected in 637 samples and the average detection among all samples where perchlorate was found was 9.85 ppb. At the highest exposure levels, FDA’s data show ed exposure from food was roughly 12 to 13 ppb.
Of note, FDA continues to recommend that consumers not alter their infant‟s or child’s diet or eating habits based on current perchlorate data.