ATSDR 2020 — Toxicological Profile for Lead
The August 2020 ATSDR Toxicological Profile for Lead is the current US government comprehensive toxicology reference for lead. Prepared by the Agency for Toxic Substances and Disease Registry (ATSDR) under CERCLA section 104(i), with peer review by an interagency Minimal Risk Level (MRL) Workgroup including ATSDR, NCEH, NIOSH, EPA, and NTP, this profile is the public-health reference document underlying CDC blood lead reference value updates, EPA risk assessments, and US state-level lead exposure investigations. ATSDR did not derive Minimal Risk Levels for lead in this profile because the developmental-neurotoxicity literature establishes effects at blood lead concentrations below the limit of confident measurement; no demonstrated threshold for the most sensitive endpoint exists. This is a settled position across major regulatory bodies.
Key numbers
No MRLs derived for lead (any route or duration) due to absence of a demonstrated effect threshold. CDC blood lead reference value (BLRV): 3.5 µg/dL (used as the operational reference for child lead exposure surveillance in the US). Version history: first released April 1993, revised August 2007, draft for public comment May 2019, final released August 2020. The profile characterizes toxicologic properties of lead across acute, intermediate, and chronic exposures; key health effects documented include developmental neurotoxicity (children), cardiovascular effects (adults), renal toxicity, and reproductive effects. Dietary exposure is addressed as a major pathway alongside inhalation and dermal routes.
Note: FM_4509523 in the same directory is a different paper (the Korean KRIEFS integrated exposure assessment study by Lim et al. 2015, EHT). The long-named directory FM_4509523_Korean_research_project_on_the_integrated_exposure_assessmen contains the ATSDR 2020 Lead Toxicological Profile. The near_duplicate field points to FM_4509523 as a co-located handle that should not be confused with this document; they are distinct papers.
Methods (brief)
Comprehensive systematic review and integration of peer-reviewed toxicological literature, epidemiological evaluations, and agency risk assessments. No primary data collection. Peer-reviewed by nongovernmental panel; reviewed by CDC and Federal scientists. Prepared under CERCLA statutory mandate.
Implications
Certification: the no-safe-threshold conclusion is the durable public-health framing that HMT&C lead-thresholds for finished products must reflect. The CDC BLRV of 3.5 µg/dL translates to FDA’s interim reference level (IRL) of 2.2 µg/day dietary lead for children ≤6 years.
Courses: the absence of MRLs for lead, contrasted with ATSDR’s quantitative MRLs for cadmium and other metals, is a teachable example of how endpoint structure constrains regulatory methodology; covers all exposure routes including dietary.
App: directly relevant to lead risk framing; the profile establishes that there is no safe dietary lead level for children.