Are there safe limits for perchlorate?
Yes; in 2003 the National Research Council of the National Academy of Sciences recommended a Reference Dose (RfD) of 0.7 micrograms per kilogram body weight per day (mcg/kg bw/d) for perchlorate. The U.S. Environmental Protection Agency (EPA) defines RfD as “an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects over a lifetime.” In 2005, the EPA adopted the RfD, which includes a 10-fold safety factor. This means if the RfD were 10-times larger there would likely be no appreciable risk of deleterious effects over a lifetime.
