BEHAVIOR OF URINARY 2,5-HEXANEDIONE IN OCCUPATIONAL COEXPOSURE TO N-HEXANE AND ACETONE

We analysed the relationship between free 2,5-hexanedione (2,5-HD) and total 2,5-HD in the urine of 87 workers exposed to n-hexane and other solvents (hexane isomers, acetone and toluene), in relation to differ ent working conditions. The concentration of free 2,5-HD in urine of w orkers exposed to Ii-hexane was about 12% of total urinary 2,5-HD. The most significant correlation (r = 0.936) was that of total 2,5-HD in urine with environmental n-hexane and exhaled air. With equal exposure to n-hexane, the concentrations in urine of free and total 2,5-HD inc reased when cutaneous absorption was involved (gloves not used), durin g the working week and with co-exposure to acetone. An analysis of the relationship between combined exposure to acetone and urinary concent rations of the various forms of 2,5-HD suggests that acetone might inf luence the toxicokinetics of n-hexane, increasing the proportion of fr ee 2,5-HD.