Monitoring exposure to chromic acid in chromeplating by measuring chromium in urine.

With personal air samplers, exposure to hexavalent chromium was measured in a group of eight chromeplaters during a period of 5 d; urine samples were collected at all times of urination for 7 d. The concentration of chromium in the urine increased from Monday morning to Tuesday afternoon and then remained constant within the group as a whole throughout the rest of the work week. In a large group of 90 chromeplaters exposure was measured for 1 d, and urine samples were collected before and after the workshift on Monday and Thursday of the same week. There was a correlation between the exposure and the concentration of chromium in postshift urine samples on Thursday (correlation coefficient 0.71). Concentrations of chromium in urine of less than or equal to 100 nmol/l indicate time-weighted average values of exposure of about or below 2 micrograms/m3. Below this exposure no severe damage to the nasal septum and no influence on lung function have been found. After the initial measuring of the airborne hexavalent chromium and the concentrations of chromium in the urine of exposed workers, urine analyses are recommended for follow-up controls.