IRIS

Trichloroethylene

CASRN 79-01-6

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (63 pp, 520 K) last updated: 09/28/2011

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Developmental, Immune 5 x 10-4 (See Note) High


Note: The RfD was derived as a midpoint among three similar candidate RfDs—0.00048 mg/kg-day for decreased thymus weight in mice (Keil et al., 2009), 0.00037 mg/kg-day for developmental immunotoxicity (decreased PFC and increased delayed-type hypersensitivity) in mice (Peden-Adams et al., 2006), and 0.00051 mg/kg-day for fetal heart malformations in rats (Johnson et al., 2003). See Section I.A.1 of the IRIS Summary for Trichloroethylene for more information.

 


Reference Concentration for Inhalation Exposure (RfC) (PDF) (63 pp, 520 K) last updated: 09/28/2011

System RfC (mg/m3) Basis PoD Composite UF Confidence
Developmental, Immune 2 x 10-3 (See Note) High


Note: The RfC was derived as the midpoint of two similar candidate RfCs—0.0019 mg/m3 for decreased thymus weight in mice (Keil et al., 2009) and 0.0021 mg/m3 for fetal heart malformations in rats (Johnson et al., 2003). See Section I.B.1 of the IRIS Summary for Trichloroethylene for more information.

 

Cancer Assessment

Weight of Evidence for Cancer (PDF) (63 pp, 520 K) last updated: 09/28/2011

WOE Characterization Framework for WOE Characterization
Carcinogenic to humans Guidelines for Carcinogen Risk Assessment (US EPA, 2005)
Basis:
  • Following U.S. EPA (2005b) Guidelines for Carcinogen Risk Assessment, TCE is characterized as "carcinogenic to humans" by all routes of exposure.
  • This may be a synopsis of the full weight-of-evidence narrative.

WOE Footnote:  EPA has concluded, by a weight of evidence evaluation, that Trichloroethylene is carcinogenic by a mutagenic mode of action. Age-dependent adjustment factors (ADAFs) should be used when estimating age-specific cancer risks. See IRIS Summary.


Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (63 pp, 520 K)

Oral Slope Factor: 4.6 x10 -2 per mg/kg-day
Extrapolation Method: PBPK model-based route-to-route extrapolation of the inhalation unit risk estimate for kidney cancer with a factor of 5 applied to include non-Hodgkin's lymphoma (NHL) and liver cancer risks, combined risk
Tumor site(s): Hematologic, Hepatic, Urinary
Tumor type(s): Renal cell carcinoma, non-Hodgkin's lymphoma, and liver tumors (Charbotel et al., 2006 EPA, 2011 Raaschou-Nielsen et al., 2003)



Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (63 pp, 520 K)

Inhalation Unit Risk: 4.1 x10 -6 per µg/m3
Extrapolation Method: Low-dose linear extrapolation from the point of departure (LEC01) with a factor of 4 applied to include non-Hodgkin's lymphoma (NHL) and liver cancer risks, combined risk
Tumor site(s): Hematologic, Hepatic, Urinary
Tumor type(s): Renal cell carcinoma, non-Hodgkin's lymphoma, and liver tumors (Charbotel et al. 2006 EPA, 2011 Raaschou-Nielsen et al., 2003)


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