SIGNIFICANCE OF DERMAL AND RESPIRATORY UPTAKE IN CREOSOTE WORKERS - EXPOSURE TO POLYCYCLIC AROMATIC-HYDROCARBONS AND URINARY-EXCRETION OF 1-HYDROXYPYRENE

Objectives-To evaluate workers' exposure in a creosote impregnation pl ant by means of ambient and biological monitoring. Methods-Naphthalene (vapour phase) and 10 large molecular polycyclic aromatic hydrocarbon s (PAHs) (particulate phase) were measured in the breathing zone air d uring an entire working week. 1-Hydroxypyrene (1-HP) was measured in 2 4 hour urine as a metabolite of the pyrene found in neat (dermal expos ure) and airborne creosote. Results-Naphthalene (0.4-4.2 mg/m(3)) show ed 1000 times higher concentrations in air than did the particulate PA Hs. In total, the geometric mean (range) of three to six ring PAHs was 4.8 (1.2-13.7) mu g/m(3); pyrene 0.86 (0.23-2.1) pg/m(3), and benzo(a )pyrene 0.012 (0.01-0.05) mu g/m(3). There was no correlation between pyrene and gaseous naphthalene. The correlations between pyrene and th e other nine particulate PAHs were strong, and gave a PAH profile that was similar in all air samples: r = 0.83 (three to six ring PAHs); r = 0.81 (three ring PAHs); r = 0.78 (four to six ring PAHs). Dermal exp osure was probably very high in all workers, because the daily output of urinary 1-HP exceeded the daily uptake of inhaled pyrene by less th an or equal to 50-fold. Urinary 1-HP concentrations were very high, ev en on Monday mornings, when they were at their lowest (4-22 mu mol/mol creatinine). 1-HP seldom showed any net increase over a workshift (ex cept on Monday) due to its high concentrations (16 to 120 mu mol/mol c reatinine) in the morning samples. 1-HP was always lower at the end of the shift (19 to 85 mu mol/mol creatinine) than in the evening (27 to 122), and the mean (SD) change over the working week (47 (18)) was gr eater than the change over Monday (35 (32)). The timing of 1-HP sampli ng is therefore very important. Conclusions-Urinary 1-HP proved to be a good biomarker of exposure to three to six ring PAHs but not to airb orne naphthalene. Hence, biomonitoring based on 1-HP has to be complet ed with exposure assessment for naphthalene as a marker for creosote v olatiles that mainly enter the body through the lungs.