Arsenic, Inorganic CASRN 7440-38-2 | IRIS

IRIS

Arsenic, Inorganic

CASRN 7440-38-2 | DTXSID4023886

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (29 pp, 186 K) Last Updated: 09/01/1991

System	RfD (mg/kg-day)	Basis	PoD	Composite UF	Confidence
Cardiovascular, Dermal	3 x 10 ^-4	Hyperpigmentation, keratosis and possible vascular complications	NOAEL : 8 x 10^-4 mg/kg-day	3	Medium

Reference Concentration for Inhalation Exposure (RfC) (PDF) (29 pp, 186 K)
Not assessed under the IRIS Program.

Cancer Assessment

Weight of Evidence for Cancer (PDF) (29 pp, 186 K) Last Updated: 06/01/1995

WOE Characterization	Framework for WOE Characterization
A (Human carcinogen)	Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986)

Basis:

Based on sufficient evidence from human data. An increased lung cancer mortality was observed in multiple human populations exposed primarily through inhalation. Also, increased mortality from multiple internal organ cancers (liver, kidney, lung, and bladder) and an increased incidence of skin cancer were observed in populations consuming drinking water high in inorganic arsenic.
This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (29 pp, 186 K)

Oral Slope Factor: 1.5 per mg/kg-day
Drinking Water Unit Risk: 5 x 10^-5 per µg/L
Extrapolation Method: Time- and dose-related formulation of the multistage model
Tumor site(s): Dermal
Tumor type(s): Skin cancer (Tseng, 1977; Tseng et al., 1968; U.S. EPA, 1988)

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (29 pp, 186 K)

Inhalation Unit Risk: 4.3 x 10^-3 per µg/m³
Extrapolation Method: Absolute-risk linear model
Tumor site(s): Respiratory
Tumor type(s): Lung cancer (Brown and Chu, 1983a,b,c; Lee-Feldstein, 1983; Higgins, 1982; Enterline and Marsh, 1982)

Program Outlook Details

Public Assessment Materials	Date
Problem Formulation Materials/IRIS Assessment Plan	Nov-2012
Preliminary Assessment Materials/Systematic Review Protocol	May-2019
Public Comment	Oct-2023
External Peer Review	Dec-2023
Post Final Assessment	TBD

Note: Any future dates displayed in the table above should be considered estimates and are subject to change. Once the external peer review is complete, estimated dates for release of the final assessment will be published. For the latest information on the status of this assessment, please refer to the IRIS Program Outlook. To access assessment documents, meeting materials or other supporting documents related to this assessment, visit the Chemical Documents tab. For more information about the development process, visit the IRIS Process page.

Dec 2023: BMD Model Code and BMD Modeling Results for the Inorganic Arsenic IRIS Assessment (External Review Draft) (Other)

Oct 2023: IRIS Toxicological Review of Inorganic Arsenic (Public Comment and External Review Draft) (Report)

Nov 2022: IRIS Toxicological Review of Inorganic Arsenic (Interagency Science Consultation Draft, 2022) (Report)

May 2019: Updated Problem Formulation and Systematic Review Protocol for the Inorganic Arsenic IRIS Assessment (Report)

Nov 2015: Meeting Materials for the 4th NRC Meeting on the Guidance for and the Review of EPA's Toxicological Assessment of Inorganic Arsenic (Journal)

Apr 2014: IRIS Toxicological Review of Inorganic Arsenic (Preliminary Assessment Materials, 2014) (Report)

Jan 2013: Inorganic Arsenic Workshop (Jan 2013) (Other)

Nov 2012: IRIS Toxicological Review for Inorganic Arsenic (Scoping and Problem Formulation Materials, 2012) (Report)

Sep 2012: Inorganic Arsenic Meetings & Webinars (Sep 2012 - Jul 2019) (Other)

Feb 2010: IRIS Toxicological Review of Inorganic Arsenic (Cancer) (External Review Draft, 2010) (Report)

Jun 2009: IRIS Toxicological Review of Inorganic Arsenic (Cancer) (Interagency Science Consultation Draft, 2009) (Report)

Jul 2005: IRIS Toxicological Review of Ingested Inorganic Arsenic (SAB External Review Draft, 2005) (Report)

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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