Reference Dose - Regulatory Status

Regulatory Status

Unlike National Ambient Air Quality Standards, RfDs are not enforceable standards. Instead, the EPA uses RfDs as risk assessment benchmarks and tries to set other regulations so that people are not exposed to chemicals in amounts that exceed RfDs. According to the EPA, "n aggregate daily exposure to a at or below the RfD (expressed as 100 percent or less of the RfD) is generally considered acceptable by EPA." For example, the EPA set an acute RfD for children of 0.0015 mg/kg/day for the organochlorine insecticide endosulfan, based on neurological effects observed in test animals. The EPA then looked at dietary exposure to endosulfan, and found that for the most exposed 0.1% of children age 1–6, their daily consumption of the endosulfan exceeded this RfD. To remedy this, the EPA revoked the use of endosulfan on the crops that contributed the most to exposure of children: certain beans, peas, spinach, and grapes.