HBGVs established by WHO, ATSDR and Health Canada

This is a draft position statement for discussion. This does not represent the views of the Committee and should not be cited.

25.               WHO selected a NOAEL of 6,000 μg Sb/kg bw/day from the Poon et al. (1998) study, as recommended by Lynch et al. (1999), for decreased body weight gain and reduced food and water intake. A UF of 1,000 (100 for interspecies and intraspecies differences and 10 for the short duration of the study) was applied to the NOAEL resulting in the TDI of 6.0 μg/kg bw/day (WHO 2003).

26.               ATSDR selected a NOAEL of 60 μg Sb/kg bw/day for decreases in serum glucose levels in female rats observed in the Poon et al. (1998). A UF of 100 (10 for extrapolation from animals to humans and 10 for human variability) was applied to derive an intermediate-duration (15 – 365 days) oral Minimal Risk Level (MRL) of 0.6 μg/kg bw/day (ATSDR 2019).

27.               Health Canada also selected a NOAEL of 60 μg Sb /kg bw/day from the study by Poon et al. (1998), based on observed histopathological changes in the liver (anisokaryosis) and alterations in serum biochemistry indicative of liver effects. A UF of 300 was applied (10 for interspecies variation, 10 for intraspecies variation and 3 for the use of a subchronic study) resulting in a TDI of 0.2 μg/kg bw/day (Health Canada, 2024).

28.               More information on the derivation of the HBGVs for WHO, ATSDR and Health Canada is available in the COT discussion paper TOX/2024/38.