[Field tests carried out to determine the occupational exposure to vanadium (author's transl)].

In a metallurgic plant we analysed blood samples, urine and finger-nails of 54 workers exposed to vanadium. On the basis of orientating dust measurements it can be assumed that the results obtained were, as a rule, clearly lower than the MAC values for vanadium pentoxide dust. The median vanadium concentration in whole-blood was 2.9 micrograms/l. This indicates that the exposed persons differ significantly from the control group. The median vanadium concentration measured in urine was 37.8 micrograms/l. This means that there is a significant difference in comparison with the control group (0.8 micrograms/l). In order to obtain values of greater reliability, the vanadium concentration resulting from the analysis of spontaneous urine samples was to be referred to the creatinine content. Conversion yields a medium vanadium concentration of 33.9 and 0.6 micrograms/g creatinine for the exposed workers and normal persons respectively. The cystine content found in the finger-nails of persons occupationally exposed to vanadium was significantly reduced with respect to the comparative group (8.9 against 9.9 mg cystine per 100 mg finger-nails). Within the groups of persons examined no correlation is found to exist between the cystine content of the finger-nails and the age of the persons, nor between the vanadium concentrations in blood and urine. After a weekend without exposure the vanadium concentrations in blood and urine dropped. In general, this drop was the more pronounced the higher the initial value was. Roughly two to four days after the occupational exposure had ceased, the values dropped to the half of the initial value. Based on the test results available, the vanadium concentrations in blood and urine reflect the extent of an occupational vanadium exposure and are suitable indicators for estimating the potential threat caused by this heavy metal.