All such efforts will help sharpen the insights possible from data on residues in food. After briefly reviewing our data sources, methodology, and major findings, Winter points out that our scoring system is sensitive to scientific judgments the EPA makes in setting Reference Doses. This is, of course, true. Some will change. When we update our analysis, which we expect to do at least annually, as new PDP data sets come out, we will, of course, use the latest EPA RfDs.
Winter focuses on the report's discussion of the risk from methyl parathion.
He criticizes CU for using chronic Reference Doses for assessment of daily individual acute exposure and risks. This is a good point to raise, and one we thought about a lot before choosing to use on chronic RfDs. This is probably correct for cancer risks, where the scientific community does generally accept that periodic spikes in exposure are less important than average daily exposures over many years. Toxicologists have known for many years that some adverse health effects can be expressed only long after short-term exposures. For instance, a spike of exposure during a critical stage of fetal development or during the period shortly after birth may produce changes in brain function that show up later in the organism's life as a behavioral or learning deficit.