Lead (inorganic) — biological monitoring
When to suspect: Battery mfg / recycling, smelting, soldering, paint & pigment, radiator repair, scrap & e-waste, glass / ceramics.
Blood lead level (BLL) (µg/dL)
| Level | Interpretation |
|---|---|
| < 3.5 | Non-exposed adult reference (CDC/NIOSH BLRV) |
| ≥ 5 | NIOSH ABLES "elevated" adult surveillance threshold |
| 20 | ACGIH BEI (sampling time not critical) |
| ≥ 50 / ≥ 60 | OSHA medical removal (6-mo avg ≥ 50, or single ≥ 60); return at ≤ 40 |
Effect markers: ZPP (normal < 100 µg/100 mL; rises once BLL > 40) and δ-ALA in urine (rises exponentially > 40).
Biological exposure index
ACGIH BEI = 20 µg/dL (lowered from 30 in 2018). OSHA 29 CFR 1910.1025 sets the removal/return levels.
Basis: ACGIH BEI 20 µg/dL; OSHA 1910.1025 App C; CDC/NIOSH adult BLRV 3.5 µg/dL.
Sample collection & preparation
- Trace-metal-free royal-blue-top K2EDTA tube (never glass; EDTA preferred over heparin).
- Sampling time NOT critical (lead accumulates; long half-life).
- Wash puncture site (soap/water then alcohol, no iodine) + hands; remove work clothing to avoid lead-dust contamination. No fasting.
Statutory basis. Factories Act 1948 sets only AIR limits (Second Schedule TWA/STEL, s.41F) and mandates the hazardous-process exam (s.41C, ≤12-monthly); it gives NO blood/urine values. The ranges below are ACGIH BEI / OSHA / clinical benchmarks (India has not adopted biological limits into law).
Reference information for occupational-health professionals — not medical advice, and not a substitute for examination by a qualified physician.
All 27 agents — toxicology & biological monitoring
MedFactory — Occupational Health Centre software for Indian factories