Biomonitoring of industrial solvent exposures in workers' alveolar air

Ten different solvents, viz., toluene, styrene, methylethyl ketone, acetone, dimethylformamide, cyclohexane, n-hexane, methylcyclopentane, 2-methylpentane, and 3-methylpentane were determined in environmental air and in the alveolar air of workers during the work shift. As regards all ten solvents studied, alveolar concentration (Ca) and the difference between environmental concentration (Ci) and alveolar concentration (Ci-Ca), were correlated with environmental concentration. According to the slopes of the regression lines, the ratio between alveolar and environmental concentration (Ca/Ci) and the alveolar retention ((Ci-Ca)/Ci) in the case of all ten solvents studied were complementary, i.e., their sum was equal to unity. The solvents with high solubility in blood, i.e., toluene, styrene, methylethyl ketone, acetone, and dimethylformamide showed a Ca/Ci ratio lower than 0.5 and the solvents with low solubility, i.e., cyclohexane, hexane, and their isomers showed a Ca/Ci ratio higher than 0.5. According to the findings which prove that the alveolar concentration of all solvents studied during the work shift is a function of variations in the environmental concentrations it seems reasonable to suggest the use of alveolar tests for monitoring environmental exposure to solvents during the work shift.