Interspecies variability

Uncertainty factors An uncertainty factor of 10 was used for interspecies variability to account for possible variability in arsine-induced hemolysis and progression to renal effects. An uncertainty factor of 3 was used for intraspecies variability assuming limited individual variability in hemolytic response (described more fully under AEGL-2 and AEGL-3). 

Uncertainty factors An uncertainty factor of 3 for interspecies variability was applied because the toxic response to dimethylhydrazine... 

Substantial interspecies variability exists in sensitivity to free cyanide (Smith et al. 1979 USEPA 1980). 

Uncertainty factors 3 for interspecies variability 3 for intraspecies variability... 

Wyman, J.F., B.H.Gray, L.H.Hill, J.Coleman, C.Flemming, and D.E.Uddin. 1985. Interspecies variability in propylene glycol dinitrate-induced methemoglobin formation. Toxicol. Appl. Pharmacol. 81 203-212. 

Intermediate-duration oral studies in humans for mirex are lacking. A review of the animal oral intermediate toxicity data for mirex indicates that the available studies are not adequate to derive intermediate oral MRL for mirex. The most suitable study provides a LOAEL of 0.25 mg/kg/day for endocrine effects-dilation of rough endoplasmic reticulum cisternae of the thyroid of weanling Sprague-Dawley rats (Singh et al. 1985). Adjusting the LOAEL of 0.25 mg/kg/day determined from this study with a total uncertainty factor of 1,000 (10 for use of a LOAEL, 10 for animal to human extrapolation, and 10 for interspecies variability) yields an intermediate oral MRL of 0.0003 mg/kg/day, which is lower than the chronic-duration oral MRL of 0.0008 mg/kg/day derived from an NTP (1990) study in rats (see chronic-duration MRL). Therefore, no oral intermediateduration MRL was developed for mirex. 

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