Toxicological Profile for Lead

Summary

The August 2020 ATSDR Toxicological Profile for Lead is the current US comprehensive toxicology synthesis for lead. ATSDR does not derive Minimal Risk Levels for lead in this profile because there is no demonstrated threshold for the most sensitive endpoint (developmental neurotoxicity in children); the conclusion that no safe level of lead exposure has been identified for children is a settled position across the major regulatory bodies. The profile is the public-health reference document underlying CDC blood lead reference value updates, EPA risk assessments, and US state-level lead exposure investigations.

Key numbers

ATSDR has not derived Minimal Risk Levels (MRLs) for lead in any route or duration because of the absence of a demonstrated effect threshold. This is a deliberate methodological position rather than a data gap: the developmental-neurotoxicity literature establishes effects at blood lead concentrations below the limit of confident measurement, and ATSDR cites this as the reason that traditional NOAEL/LOAEL-based MRL derivation is not appropriate for lead. Quantitative reference values for US public-health work derive instead from CDC’s blood lead reference value (BLRV) of 3.5 µg/dL.

Implications

• Certification: the no-safe-threshold conclusion is the durable public-health framing that HMT&C lead-thresholds for finished products should reflect; calibration to the CDC BLRV via dietary translation (FDA’s IRL of 2.2 µg/day for children) is the operational pathway.
• Courses: the absence of MRLs for lead in this 2020 profile, contrasted with ATSDR’s quantitative MRLs for cadmium and other metals, is a teachable example of how endpoint structure constrains regulatory methodology.

Wiki pages updated on ingest

• Lead

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