Hexachlorodibenzo-p-dioxin (HxCDD), mixture of 1,2,3,6,7,8-HxCDD and 1,2,3,7,8,9-HxCDD CASRN 57653-85-7 | IRIS

IRIS

Hexachlorodibenzo-p-dioxin (HxCDD), mixture of 1,2,3,6,7,8-HxCDD and 1,2,3,7,8,9-HxCDD

CASRN 57653-85-7 | DTXSID0023824

IRIS Summary (PDF) (10 pp, 102 K)

Key IRIS
Values
Other EPA
Information

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (10 pp, 102 K) Last Updated:
Not assessed under the IRIS Program.

Reference Concentration for Inhalation Exposure (RfC) (PDF) (10 pp, 102 K)
Not assessed under the IRIS Program.

Cancer Assessment

Weight of Evidence for Cancer (PDF) (10 pp, 102 K) Last Updated: 03/31/1987

WOE Characterization	Framework for WOE Characterization
B2 (Probable human carcinogen - based on sufficient evidence of carcinogenicity in animals)	Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)

Basis:

Hepatic tumors in mice and rats by gavage
This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (10 pp, 102 K)

Oral Slope Factor: 6.2 x 10³ per mg/kg-day
Drinking Water Unit Risk: 1.8 x 10^-1 per µg/L
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Liver tumors (adenomas and carcinomas; neoplastic nodules and hepatocellular carcinomas) (NTP, 1980a)

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (10 pp, 102 K)

Inhalation Unit Risk: 1.3 per µg/m³
Extrapolation Method: Linearized multistage procedure, extra risk
Tumor site(s): Hepatic
Tumor type(s): Liver tumors (adenomas and carcinomas; neoplastic nodules and hepatocellular carcinomas) (NTP, 1980a)

Additional EPA toxicity information may be available by visiting the following sites:

Human Health Benchmarks for Pesticides (HHBP). This database provides human health benchmarks for pesticides that may be present in drinking water.
Office of Pesticide Programs Pesticide Chemical Search. This database provides links to health effects information and registration status for pesticides.
Chemistry Dashboard. This database provides information on chemical structures, experimental and predicted physicochemical, and toxicity data.

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