Metribuzin

CASRN 21087-64-9

Health Hazard Assessments for Effects Other than Cancer


Reference Dose for Oral Exposure (RfD) (PDF) (14 pp, 117 K) last updated: 01/31/1987

RfD (mg/kg-day) System Basis PoD Composite UF Confidence
2.5 x10-2 Hepatic, Urinary, Other Liver and kidney effects, decreased body weight, mortality NOEL : 2.5
mg/kg-day
100 Medium

Reference Concentration for Inhalation Exposure (RfC) (PDF) (14 pp, 117 K)
Not assessed under the IRIS Program.

Cancer Assessment


Weight of Evidence for Cancer (PDF) (14 pp, 117 K) last updated: 12/01/1993

WOE Characterization Framework for WOE Characterization
D (Not classifiable as to human carcinogenicity) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Basis:
  • No human data and inadequate evidence ffom animal bioassays. Metribuzin did not increase the incidence of tumors in a lifetime dietary study using CD-1 mice when compared with both concurrent and historic controls. In a 2-year feeding study in Wistar rats, no significant differences in neoplastic findings between the test and control groups were found. Short-term studies in bacteria and mammalian systems suggest that metribuzin is not mutagenic.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (14 pp, 117 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (14 pp, 117 K)

Not assessed under the IRIS Program.

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