Mercury — biological monitoring
When to suspect: Chlor-alkali, thermometer / lamp & e-waste recycling, dental amalgam, gold extraction, instrument mfg.
Urinary mercury (inorganic/elemental) · Blood mercury (organic) (µg/g creat · µg/L)
| Level | Interpretation |
|---|---|
| Urine < 4–5 | Non-exposed background (µg/g creatinine) |
| Urine 20 | ACGIH BEI, inorganic Hg — sampled PRE-SHIFT |
| Blood 15 | ACGIH BEI, inorganic Hg — end-of-shift/end-of-workweek (µg/L) |
| Blood 5.8 | EPA/ATSDR methyl-mercury reference (public-health, not a BEI) |
Inorganic/elemental → urine (chronic). Organic (methyl) → blood. No ACGIH BEI for organic/alkyl mercury.
Biological exposure index
ACGIH BEI: urine inorganic Hg 20 µg/g creatinine (pre-shift); blood inorganic Hg 15 µg/L (EOS/EOW). No BEI for organic mercury.
Basis: ACGIH BEI; EPA IRIS / ATSDR for the 5.8 µg/L methyl-mercury reference.
Sample collection & preparation
- Urine: clean acid-washed / trace-element-free plastic, NO metal cap, no dye; no preservative. Blood: royal-blue-top EDTA.
- Urine inorganic Hg = PRE-SHIFT; blood inorganic Hg = end-of-shift at end-of-workweek; creatinine-correct spot urine.
- Avoid seafood/fish ~48–72 h before (organic mercury inflates totals).
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