Closure Spring 2013

Q. In the draft made by FDA concerning bisphenol A in food contact applications, they present their final result as one NOAEL value, but at the same time describes how they have used two different margin of safety for infants and adults (approximately 2,000 and 27,000 for infants and adults, respectively). But if they have concerned two so different margins of safety, why is there then only one and not two NOAEL value?

A. The NOAEL, no observable adverse effects level, is the highest dose at which there were no observed effects.  One then divides the NOAEL by some factor of safety to arrive at a “safe” dose.  That might be the RfD or RfC we discussed earlier, or it may be regulation or advisory that the agency issues.  It would be logical to have two different advisory warnings, one for a product in use by infants and one for a product used by adults.  It is very common to have special precautions for chemical exposure for pregnant women.