Perchlorate (ClO4) and Perchlorate Salts

CASRN 7790-98-9

Health Hazard Assessments for Effects Other than Cancer


Reference Dose for Oral Exposure (RfD) (PDF) (22 pp, 157 K) last updated: 02/18/2005

RfD (mg/kg-day) System Basis PoD Composite UF Confidence
7 x10-4 Endocrine Radioactive iodide uptake inhibition (RAIU) in the thyroid NOEL : 7 x10-3
mg/kg-day
10 High

Reference Concentration for Inhalation Exposure (RfC) (PDF) (22 pp, 157 K) last updated: 02/18/2005
Information reviewed but value not estimated.

Cancer Assessment


Weight of Evidence for Cancer (PDF) (22 pp, 157 K) last updated: 02/18/2005

WOE Characterization Framework for WOE Characterization
Not likely to be carcinogenic to humans Revised Draft Guidelines for Carcinogen Risk Assessment (US EPA, 1999)
Basis:
  • Under U.S. EPAs 1999 Draft Revised Guidelines for Carcinogen Risk Assessment, perchlorate is not likely to pose a risk of thyroid cancer in humans, at least at doses below those necessary to alter thyroid hormone homeostasis, based on the hormonally-mediated mode of action in rodent studies and species differences in thyroid function.
  • This may be a synopsis of the full weight-of-evidence narrative.

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (22 pp, 157 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (22 pp, 157 K)

Not assessed under the IRIS Program.

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