ETHNIC-DIFFERENCES IN BIOLOGICAL MONITORING OF SEVERAL ORGANIC-SOLVENTS .2. A SIMULATION STUDY WITH A PHYSIOLOGICALLY-BASED PHARMACOKINETICMODEL

To improve the reliability of biological monitoring and the developmen t of biological limit values, ethnic differences in the biological mon itoring of several organic solvents were studied in Orientals and Cauc asians, Six Caucasian and six Oriental volunteers were exposed to each organic solvent in an exposure chamber for 6 h at rest. The exposure concentrations were 50 ppm for perchloroethylene, 50 ppm for styrene, and 100 ppm for m-xylene, respectively. Experimental results were comp ared with simulation results of a physiologically based pharmacokineti c (PB-PK) model. Differences between Orientals and Caucasians under oc cupational exposure were also estimated by extrapolation. The simulati on results obtained for the Caucasian group showed good agreement with the experimental results. However, the Oriental group did not show go od agreement when the same metabolic parameters values applied to Cauc asians were used in the PB-PK model. By modification of the metabolic parameters it was possible to get a good fit between the model and the results of the Oriental group. The simulation results obtained for oc cupational exposure also showed differences in biological levels betwe en the two ethnic groups. Implications of these differences between ex perimental and simulation results are discussed in the context of the application of biological monitoring and in the development of biologi cal limit values.