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||
: 5 x 10-2
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||
(HEC): 5 x 10-2
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)|
- 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.
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)
Not Assessed under the IRIS Program.
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