Normal chromium levels in urine and blood of Japanese subjects determined by direct flameless atomic absorption spectrophotometry, and valency of chromium in urine after exposure to hexavalent chromium.

Two hundred and thirty one urine and 20 blood samples of Japanese subjects from 4 geographic areas without known chromium pollution were assayed for chromium by direct flameless atomic absorption spectrophotometry. Normal chromium level in urine of Japanese subjects was 0.41 microg/L on an average. Urine level was less than 0.8 microg/L for all age and sex groups. Chromium levels in 2 hour urines did not correlate with those in 24 hours urine. Blood level of chromium was 2.9 ng/mL. A rabbit given an oral administration of 100 mg hexavalent chromium excreted 8.2 mg in 15 days after administration. No hexavalent chromium could be detected in urine. Ninety percent of the urinary excretion occurred within 2 days of administration.