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Table 1 Summary of default assessment factors used in human health risk assessment (adapted from ECHA 2008)

From: Dispelling urban myths about default uncertainty factors in chemical risk assessment – sufficient protection against mixture effects?

Assessment factors WHO-IPCS[17][22][33][39] USEPA[46] ECETOC[1] Danish EPA[47] UBA/BAuA[3][48] TNO/RIVM[5][49] KEMI[4] ECHA Guidance[45]
Database adequacy 1-10    1-100   1 1-5 1
LOAEL to NOAEL 3-10 10 3   10 1-10 3-10 3
Severity of Effect 1-10      1 1-10  
Duration of exposure   10       
Sub-chronic to chronic    2   2-3 10 3 2
Sub-acute to sub-chronic      2–3 10 8 3
Sub-acute to chronic    6   6-7 50-100 24 6
Interspecies 10 10   10   10 10  
Toxicokinetics 4.0       4  
Allometric scaling         
Mouse    7   7    7
Rat    4   4    4
Monkey    2   2 or 4    2
Dog    2   2    1.4
toxicodynamics 2.5     2-3   2.5 2.5
Intraspecies 10 10 5 10 25 10 10-16 10
Toxicokinetics 3.16     8   3–5  
Toxicodynamics 3.16     3   3.16  
Modifying factor   ≤10