I would like to understand your opinion about using factors such as 9 NOEL-to-ED50 or 4.1 rat-to-human to calculate ED50 data from NOAEL.
ED50 = (136 mg/kg/day * 9 NOEL-to-ED50 * 70 kg * 70 years * 365 days/year) /
(4.1 rat-to-human * 1 chronic-to-chronic * 106 mg/kg)
= 535.16 kg/person/lifetime
Do you have additional literature that shows how you have calculated them?
Extrapolation factors in USEtox for human health are all based on scientific literature. Please read Rosenbaum et al., 2008 (pp. 538-539), Rosenbaum et al., 2011 (pp. 721-723), and the official USEtox® User Manual (pp. 18 ff.) all referring to Huijbregts et al., 2005 for e.g. extrapolation from NOEL to ED50 or from rat to human exposure.