Flannery, Dolan, Hoffman-Pennesi, Gavelek, Jones, Kanwal, Wolpert, Gensheimer, Dennis, Fitzpatrick 2020 — FDA interim reference levels for dietary lead exposure
This Regulatory Toxicology and Pharmacology paper from a 10-author FDA team derives and documents the U.S. FDA Interim Reference Levels (IRLs) for dietary lead exposure in children and women of childbearing age. The IRLs are the FDA’s operational dietary-Pb-exposure benchmark for the FDA Closer-to-Zero program: 2.2 µg/day for children (interpreted at the corresponding age groups) and 8.8 µg/day for women of childbearing age. These IRLs translate the CDC blood-lead reference value (5 µg/dL at the time of derivation, since updated to 3.5 µg/dL) into a dietary-equivalent intake using IEUBK and adult kinetic models, and serve as the action-level-development anchor for FDA action levels in juice (target 5 ppb), infant rice cereal (target 100 ppb iAs), and processed baby food (target 10/20 ppb).
Key conclusions
Children’s IRL: 2.2 µg/day (corresponding to a 5 µg/dL blood-lead-reference dietary equivalent at the IEUBK model). Women-of-childbearing-age IRL: 8.8 µg/day (corresponding to maintaining maternal blood-lead below 5 µg/dL during pregnancy with appropriate margin). The IRLs are explicitly interim, are not action levels themselves, and operate as the FDA’s exposure-assessment-floor against which dietary intake estimates are compared. Action levels in specific FDA guidance documents (juice, infant rice cereal, processed baby food) are derived from achievability and feasibility considerations applied against this exposure floor, not directly from the IRLs.
Implications
- Certification: Authoritative FDA-derived dietary-Pb exposure floor. Useful as a citing reference for HMTc thresholds that explicitly aim to keep dietary intake below the IRLs at the vulnerable-population age groups. The IRLs are the FDA’s quantitative bridge between blood-lead biomarker reference values and dietary-product action levels.
- Courses: Standard FDA reference for the dietary-to-blood-lead translation methodology.