Fluazifop

Summary

Abstract

The Food Safety of Commission (FSCJ) conducted a risk assessment of fluazifop (fluazifop-butyl (racemate): CAS No. 69806–50–4 and fluazifop-P-butyl (R-selective): CAS No. 79241–46–6), aryloxy phenoxypropionic acid herbicides, based on results from various studies. Fluazifop-butyl and fluazifop-P-butyl show bioequivalence in pharmacokinetics in the following animal experiments, and thus data on both the chemicals were used for the assessment irrespective of the chemical forms. The lowest no-observed-adverse-effect level (NOAEL) obtained in all the studies was 0.44 mg/kg bw/day in a two-year combined chronic toxicity/carcinogenicity study of fluazifop-butyl in rats. FSCJ specified the acceptable daily intake (ADI) of 0.0044 mg/kg bw/day, applying a safety factor of 100 to the NOAEL. The lowest NOAEL for adverse effects that would be likely to be elicited by a single oral administration of fluazifop-butyl or fluazifop-P-butyl was 2 mg/kg bw/day obtained in developmental toxicity studies of fluazifop-P-butyl in rats and rabbits. Applying a safety factor of 100 to the NOAEL, FSCJ specified the acute reference dose (ARfD) of 0.02 mg/kg bw for women of child-bearing ages. For general population, the lowest NOAEL of a single oral administration of fluazifop was 948 mg/kg bw obtained in an acute toxicity study of fluazifop-P-butyl in rats. FSCJ, thus, considered it unnecessary to specify ARfD due to the NOAEL above the cut-off level (500 mg/kg bw).