ATSDR 2007 — Toxicological Profile for Arsenic
Summary
The August 2007 ATSDR Toxicological Profile for Arsenic is a comprehensive synthesis of inorganic and organic arsenic toxicology under CERCLA Section 104(i). The profile derives Minimal Risk Levels for inhalation and oral routes of exposure to inorganic arsenic, the species responsible for human carcinogenicity. The 2007 vintage is older than the 2012 cadmium and 2020 lead ATSDR profiles in this corpus, and pre-dates the EPA IRIS 2025 reassessment of inorganic arsenic; it remains the operative ATSDR reference for arsenic toxicology in US public-health practice.
Key numbers
ATSDR derived oral and inhalation Minimal Risk Levels for inorganic arsenic in this profile. The chronic oral MRL is anchored on dermal effects (hyperpigmentation, palmar/plantar keratosis, skin lesions) observed in chronically exposed populations (Tseng et al. Taiwanese cohort and others); the chronic oral MRL is 0.0003 mg As/kg/day (0.3 µg As/kg/day). Inhalation MRLs cover acute and intermediate durations. The arsenic carcinogenicity classification is consistent with IARC Group 1 (lung, bladder, skin cancers) with quantitative cancer slope factors derived through EPA IRIS rather than through ATSDR.
| Route | Duration | MRL |
|---|---|---|
| Oral | Acute | Not derived |
| Oral | Intermediate | Not derived |
| Oral | Chronic (≥1 year) | 0.3 µg As/kg/day (3 × 10⁻⁴ mg As/kg/day) |
| Inhalation | Acute | Not derived |