OCCUPATIONAL EXPOSURE TO HEXAHYDROPHTHALIC ANHYDRIDE - AIR ANALYSIS, PERCUTANEOUS-ABSORPTION, AND BIOLOGICAL MONITORING

Urinary hexahydrophthalic acid (HHP acid) levels were determined in 20 workers occupationally exposed to hexahydrophthalic anhydride (HHPA) air levels of 11-220 mug/m3. The levels of HHP acid in urine increased rapidly during exposure and the decreases were also rapid after the e nd of exposure. The elimination half-time of HHP acid was 5 h, which w as significantly longer than in experimentally exposed volunteers, pos sibly indicating distribution to more than one compartment. There was a close correlation between time-weighted average levels of HHPA in ai r and creatinine-adjusted levels of HHP acid in urine collected during the last 4 h of exposure (r = 0.90), indicating that determination of urinary HHP acid levels is suitable as a method for biological monito ring of HHPA exposure. An air level of 100 mug/m3 corresponded to a po stshift urinary HHP acid level of ca. 900 nmol/mmol creatinine in subj ects performing light work for 8h. Percutaneous absorption of HHPA was studied by application of HHPA in petrolatum to the back skin of thre e volunteers. The excreted amounts of HHP acid in urine, as a fraction of the totally applied amount of HHPA, were within intervals of 1.4%- 4.5%, 0.2%-1.3%, and 0%-0.4% respectively, indicating that the contrib ution from percutaneous absorption is of minor importance in a method for biological monitoring.