STERIGMATOCYSTIN

Comments:

Taking account of the available information on genotoxicity, carcinogenicity and DNA adduct formation, the Committee concluded that sterigmatocystin is genotoxic and carcinogenic, and the critical effect was determined to be carcinogenicity. As it is not appropriate to establish a health-based guidance value for substances that are genotoxic carcinogens, the Committee used an MOE approach based on the BMDL10 for sterigmatocystin of 0.16 mg/kg bw per day as the point of departure. The Committee calculated margins of exposure for mean and high estimates of dietary exposure to sterigmatocystin. The margins of exposure for adults range from 9400 to more than 530 000 for mean estimates based on upper bound (UB) and lower bound (LB) assumptions. For high estimates, margins of exposure for adults range from 4700 to 270 000. The Committee considered that the margins of exposure were not of human health concern even at the high UB exposure. Overall, the Committee concluded that the data used for calculating the margins of exposure have considerable limitations, both for the dietary exposure estimate and for the toxicological point of departure. Consequently, the derived margins of exposure should be considered only as crude estimates. The Committee also noted that sterigmatocystin and AFB1 have the same main target organ (the liver). The comparative animal data on carcinogenicity are very limited, but indicate that sterigmatocystin is less potent than AFB.

Tolerable Intake:

NOT ESTABLISHED, genotoxic carcinogen

Meeting:

83

Report: 

Tox Monograph: