IRIS

Dichlorvos

CASRN 62-73-7

Health Hazard Assessments for Effects Other than Cancer

Reference Dose for Oral Exposure (RfD) (PDF) (33 pp, 201 K) last updated: 11/01/1993

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Nervous 5 x 10-4 Plasma and RBC ChE inhibition in males and females brain ChE inhibition in males NOAEL : 5 x 10-2
mg/kg-day
100 Medium

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (33 pp, 201 K) last updated: 06/01/1994

System RfC (mg/m3) Basis PoD Composite UF Confidence
Nervous 5 x 10-4 Decreased brain cholinesterase activity NOAEL (HEC): 5 x 10-2
mg/m3
100 Medium

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (33 pp, 201 K) last updated: 10/01/1989

WOE Characterization Framework for WOE Characterization
B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals) Guidelines for Carcinogen Risk Assessment (US EPA, 1986)
Basis:
  • Significant increases in forestomach tumors in female and male B6C3F1 mice and leukemias and pancreatic acinar adenomas in Fischer 344 rats. Supporting evidence included observation of tumors at other sites in the rat and observation of mutagenicity for both dichlorvos and a major metabolite dichloroacetaldehyde. A structurally related material, dichloropropene, also induces forestomach tumors in rodents.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (33 pp, 201 K)

Oral Slope Factor: 2.9 x10 -1 per mg/kg-day
Drinking Water Unit Risk: 8.3 x10 -6 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hematologic, Gastrointestinal, Endocrine
Tumor type(s): Forestomach tumors, pancreatic acinar adenoma, leukemia (NTP, 1986a,b)



Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (33 pp, 201 K)

Not Assessed under the IRIS Program.

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