In "For Openers," Editor Greg Ettling offers his perspective on recent industry events.
Last month on page 4, I questioned whether the dispute over how to best deal with perchlorate would be able to avoid becoming an unduly raucous and mud-spattered affair. It's likely we'll be getting a good indication in short order as the U.S. Environmental Protection Agency (EPA) has gone ahead and established an official reference dose (RfD) of 0.0007 mg/kg/day of perchlorate. This level is consistent with the recommended reference dose included in the National Academy of Science's (NAS) January 2005 report. A reference dose is a scientific estimate of a daily exposure level that is not expected to cause adverse health effects in humans.
EPA says its reference dose, which assumes total intake from both water and food sources, is appropriate and protective for all populations, including the most sensitive subgroups. The selected reference dose contains a tenfold uncertainty factor to protect the most sensitive population, the fetuses of pregnant women who might have hypothyroidism or iodide deficiency. This uncertainty factor also covers variability among other human life stages, gender and individual sensitivities.