Chromium Urine Testing

Heavy Metals · Heavy Metals overview

Urinary total chromium is the recognised biomarker for hexavalent chromium exposure in welding stainless steel, hard chromium plating, chromate pigment manufacture, and chromate-treated leather operations.

Cr(VI) vs Cr(III)

Hexavalent chromium Cr(VI) is the regulated species — a Category 1A carcinogen with a UK WEL of 0.025 mg/m³ 8-h TWA. Trivalent chromium Cr(III) is essentially non-toxic at workplace concentrations. Urinary total chromium does not distinguish species, but Cr(III) absorption is minimal so workplace urinary Cr effectively reflects Cr(VI) exposure.

Reference value and timing

HSE BMGV is 10 µmol/mol creatinine for urinary chromium, sampled end-of-shift on the last day of a working week. The end-of-week timing reflects the multi-day biomarker half-life and captures cumulative weekly exposure.

Sectors

Stainless steel welding (MMA, MIG, plasma), hard chromium electroplating, chromate paint application and removal, leather tanning chromate baths, and certain refractory and pigment production.