Urinary excretion of 1-hydroxypyrene as a biomarker of exposure to polycyclic aromatic hydrocarbons from different sources

1-Hydroxypyrene (1-OHP) urinary excretion has been studied in subjects expo sed to polycyclic aromatic hydrocarbons (PAH) from different sources (urban air pollution, cigarette smoking, food contamination or occupational expos ure). In Study A, statistically significant differences among subjects cate gorized according to daily cigarette consumption were observed: 1-OHP media n excretion of heavy smokers (more than 20 cigarettes per day; 1-OHP = 371 ng l(-1); n =6) was significantly increased over that of non-smokers (1-OHP = 160 ng l(-1); n = 79), light smokers (less than 10 cigarettes per day, 1 -OHP = 157 ng l(-1); n = 7) and also medium smokers (10-20 cigarettes per d ay, 1-OHP = 154 ng l(-1); n = 13) (p < 0. 04). In smokers, 1-OHP excretion (y, ng l(-1)) increased with the intensity of cigarette consumption and was associated with self-reported number of cigarettes smoked daily (x, n) (y = 20 + 16.6x; r = 0.58, n = 22, p < 0.01), urinary thiocyanate (x, mu ol l( -1)) (y = 55 + 2.6x; r = 0.57, n = 20, p < 0.01) and cotinine (x, mu g l(-1 )) (y = 89 + 0.23x; r = 0.62, n = 17, p < 0.01). In Study B the influence o f smoked food consumption on 1-OHP excretion was evaluated: 1-OHP excretion began to increase as soon as 3 h after a PAH-rich meal and peak values wer e reached between 6 and 9 h after lunch. Maximum excretion mean values were respectively 525 ng l(-1) for non-smokers (n = 8) and 650 ng l(-1) for smo kers (n = 4). 1-OHP concentrations in next-morning samples were back to pre -lunch levels both for non-smokers and smokers. In Study C non-smoker worke rs (n = 28) occupationally exposed to PAH in a steel plant were investigate d. At values of airborne pyrene ranging between 6 and 30 mu g m(-3), excret ion values of 1-OHP up to 80 000 ng l(-1) were observed. The use of urinary 1-OHP as a screening test to discriminate between smokers and non-smokers in the presence of uncorrected dietary influence has been calculated accord ing to a cut-off value of 461 ng l(-1) (reference group upper limit): the 1 -OHP positive predictive value is 57 %, its predictive negative value is 77 %, sensitivity is 15% and specificity is 96 %. In conclusion, 1-OHP appear s to be a valuable biomarker of pyrene exposure. It will be nevertheless mo re accurate in assessing human PAH exposure from multiple sources if the in fluence of different kinetics for inhaled (particulate or gaseous) or inges ted PAH are considered and if the role of oxidative polymorphism is adequat ely elucidated. The possibility of using 1-OHP to estimate the total burden of PAH from different sources or of screening groups with different PAH ex posure appears to be a possible approach. However, the use of 1-OHP to eval uate the associated risk of cancer is still a premature target.