Category (section) Status Last Revised

2,3,7,8-Tetrachlorodibenzo-pdioxin Source Documents

• 2,3,7,8-Tetrachlorodibenzo-pdioxin Summary

• 2,3,7,8-Tetrachlorodibenzo-pdioxin Support Documents

Revision History

Date Section Description

02/17/2012 I.A. RfD added

• See IRIS Summary for

complete revision history.

Critical Effect Point of Departure*

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2,3,7,8-Tetrachlorodibenzo-p-dioxin Quickview (CASRN

1746-01-6)

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IRIS only after a comprehensive review of toxicity data by U.S. EPA

health scientists from several Program Offices, Regional Offices, and

the Office of Research and Development.

Disclaimer: This QuickView represents a snapshot of key information.

We suggest that you read the IRIS Summary to put this information

into complete context.

For definitions of terms in the IRIS Web site,refer to the IRIS

Glossary.

Status of Data for 2,3,7,8-Tetrachlorodibenzo-p-dioxin

File First On-Line: 02/17/2012;Last Significant Revision: 02/17/2012

Oral RfD Assessment Yes 02/17/2012

Inhalation RfC Assessment No

Carcinogenicity Assessment Message 02/17/2012

Synonyms

• 1746-01-6

• 2,3,7,8-tetrachlorodibenzop-dixoin

• TCDD

• Dibenzo(b,e)(1,4)dioxin,

2,3,7,8-tetrachloro-

• Dibenzo-p-dioxin,

2,3,7,8-tetrachloro-

• 2,3,7,8-TCDD

• Tetrachlorodibenzodioxin

• 2,3,7,8-Tetrachlorodibenzo(b,e)(1,4)

dioxin

• 2,3,7,8-Tetrachlorodibenzo-1,4-dioxin

• Tetradioxin

• Dioxin

Chronic Health Hazard Assessments for Noncarcinogenic Effects

Reference Dose for Chronic Oral Exposure (RfD)

UF RFD

Decreased sperm count and motility in men exposed to

TCDD as boys / Increased TSH in neonates

LOAEL (ADJ): 2 x10-8

mg/kg-day

30 7 x10-10

mg/kg-day

LOAEL (ADJ): 2 x10-8 mg/kg-day 30 7 x10-10

mg/kg-day

*The Point of Departure listed serves as a basis from which the Oral RfD was derived. See Discussion of

Conversion Factors and Assumptions for more details.

• Principal and Supporting Studies (Oral RfD)

• Epidemiologic cohort study, Mocarelli et al., (2008) / Baccarelli et al., (2008)

• Confidence in the Oral RfD

• Study -- High

• Database -- High

• RfD -- High

Reference Concentration for Chronic Inhalation Exposure (RfC)

Not Assessed under the IRIS Program.

Carcinogenicity Assessment for Lifetime Exposure

Integrated Risk Information System (IRIS)

2,3,7,8-Tetrachlorodibenzo-p-dioxin Quickview (CASRN 1746-01-6)|IRIS|USEPA Page1of2

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• Weight-of-Evidence Characterization

• Assessment underway at the time of the last significant revision.

Quantitative Estimate of Carcinogenic Riskfrom Oral Exposure

• Assessment underway at the time of the last significant revision.

Quantitative Estimate of Carcinogenic Riskfrom Inhalation Exposure

• Assessment underway at the time of the last significant revision.

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