2016 Volume 4 Issue 3 Pages 93-102
The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of glyphosate (CAS No. 1071-83-6), an amino acid herbicide, based on results from various studies. Major adverse effects of glyphosate were observed on reduced gain of body weight, GI tract (diarrhea, increased cecum weight, bowel dilatation, thickening of intestinal mucosa), and liver (increased alkaline phosphatase (ALP), hepatocellular hypertrophy). Glyphosate had no neurotoxicity, carcinogenicity, reproductive toxicity, teratogenicity, and genotoxicity. As the whole, the lowest value among no-observed-adverse-effect levels (NOAELs) was 100 mg/kg bw/day obtained in the 90-days and one-year toxicity studies in dogs, and in the developmental toxicity studies of rabbits. FSCJ thus established an acceptable daily intake (ADI) for glyphosate at 1 mg/kg bw/day, applying a safety factor of 100 to the NOAEL. The lowest NOAEL for adverse effects elicited by a single oral administration of glyphosate was 1,000 mg/kg bw observed in an acute toxicity studies in rats and mice. It is thus unnecessary to specify an acute reference dose (ARfD), due to the exceeding of the cut off level (500 mg/kg bw).