PATTERNS OF 1-HYDROXYPYRENE EXCRETION IN VOLUNTEERS EXPOSED TO PYRENEBY THE DERMAL ROUTE

The urinary excretion profiles following exposure to pyrene were estab lished in one psoriasic patient under treatment with a coal tar-based shampoo and in two other volunteers exposed to a single dose of 100 mu l creosote and, in a separate experiment, to five consecutive daily d ermal applications of 500 mu g pyrene on 200 cm(2) of the inner face o f the forearms. Timed micturitions were collected for up to 48 h follo wing exposure. Both in the psoriasic patient and in the volunteers exp osed to creosote, the excretion peaks between 10 and 15 h after applic ation and first-order apparent half lives of 11.5-15 h can be calculat ed for the elimination phase. Compatible with these observations, repe ated exposure to pyrene in the volunteers causes an increase in peak a nd trough urinary l-hydroxypyrene (1-OHP) values for the first few day s following the first exposure. These results suggest that the differe nce between beginning-of-shift/beginning of work week and beginning-of -shift/end of work week 1-OHP excretions should reflect the average ex posure of the week in workers having a constant exposure to pyrene. Th e difference between the beginning- and end-of-shift excretion values of a given day should reflect the exposure of that day but the maximum excretion would be attained a few hours after termination of exposure .