Pesticide Risk Assessment The RFD is determined by dividing the NOAEL by a uncertainty factor(UF),usually between 100 and 1000 。 10X-uncertainty in extrapolating from animal studies to humans (interspecies) 10X-to account for variation in human susceptibility (intraspecies). 。 2-10X-to account for sensitive sub-populations (infants and children)1. 2-10X-optional factor for inconsistent data OSU I FQPA requires EPA to make determination if additional factor necessary regonPesticide Risk Assessment • The RFD is determined by dividing the NOAEL by a uncertainty factor (UF), usually between 100 and 1000 • 10X – uncertainty in extrapolating from animal studies to humans (interspecies). • 10X – to account for variation in human susceptibility (intraspecies). • 2-10X – to account for sensitive sub-populations (infants and children) 1. • 2-10X – optional factor for inconsistent data 1 FQPA requires EPA to make determination if additional factor necessary