BACKGROUND URINARY 1-HYDROXYPYRENE LEVELS IN NON-OCCUPATIONALLY EXPOSED INDIVIDUALS IN THE PROVINCE OF QUEBEC, CANADA, AND COMPARISON WITH ITS EXCRETION IN WORKERS EXPOSED TO PAH MIXTURES

The urinary excretion of l-hydroxypyrene (1-OHP) was measured in two r eference groups of non-occupationally exposed individuals and in four groups of workers. Two of these groups were exposed to what were consi dered to be low levels of polycyclic aromatic hydrocarbons (PAH) on th e basis that even post-shift 1-OHP excretion values were low (< 2 mu m ol/mol creatinine). Therefore, urine samples were collected from these workers after a period of > 60 h without occupational exposure which should yield values approaching background levels. Pooling these resul ts with those of the reference groups yielded a total of 140 individua ls having a mean (geometric) excretion of 0.08 mu mol/mol creatinine a nd 5th, 50th and 95th percentiles of 0.02, 0.09 and 0.32 mu mol/mol cr eatinine. The mean (geometric) excretion in the 95 nonsmokers and 45 s mokers of this pool was 0.07 and 0.12 mu mol/mol creatinine, respectiv ely (one-tailed Student t-test, P < 0.001). Both this background excre tion and the contribution of smoking appeared small in comparison with the excretion levels observed in some groups of exposed workers. Inde ed, creosote workers described in this report had a geometric mean (ra nge) excretion of 1.63 (0.18-10.47) mu mol/mol creatinine during their working week. It is concluded that, for the biological monitoring of workers exposed to PAH, urinary 1-OHP appears to be a useful bioindica tor for which background environmental contamination or smoking habits can be neglected in most cases.