Recent advances in biological monitoring of hexavalent chromium compounds.

Intratracheal instillation of 51CrCl3 in anaesthetized rabbits resulted in partial absorption. In blood, the absorbed material was entirely confined to the plasma compartment. By contrast, after similar application of Na251CrO4 the bulk of blood radioactivity was present in red blood cells (RBC). It is suggested that Cr (VI) may enter the body not reduced via the lung and may be deposited in RBC for the cell's lifetime (approximately 110 d). Since inhalation of Cr (VI)-containing aerosols or particles is the main occupational exposure route for man, it is concluded that the chromium content of RBC could be used as a selective biological indicator for exposures to (carcinogenic) hexavalent chromium. The new theoretical concept was confirmed in a pilot study with workers of a dye pigment plant. Elevated chromium content of whole blood evoked by exposure to chromate particles correlated strongly with increased chromium values in RBC (correlation coefficient: 0.86).