Polycyclic nitroarenes (nitro-PAHs) as biomarkers of exposure to diesel exhaust

Diesel exhaust contains numerous genotoxic carcinogens. It is essentially u nknown to which extent this source contributes to the total load of these c hemicals in humans. One possible approach to the problem is to find suitabl e biomarkers. To this end five polycyclic mononitroarenes (nitro-PAH) were selected and methods developed to determine the sulfinic acid-type hemoglob in adducts they form in vivo. The nitro-PAHs are: 1-nitropyrene, 2-nitroflu orene, 3-nitrofluoranthene, 9-nitrophenanthrene, and 6-nitrochrysene. Hydro lysis of the hemoglobin adducts yields the respective arylamines which were analyzed by gas chromatography/mass spectrometry. The detection limit was 0.01-0.08 pmol/g Hb. Blood samples were analyzed from 29 bus garage workers , occupationally exposed to diesel exhaust, and from 20 urban hospital work ers and 14 rural council workers as controls. Hb adducts above the detectio n limit were found in most blood samples. The most abundant cleavage produc ts were 1-aminopyrene and 2-aminofluorene with levels ranging from 0.01 to 0.68 pmol/g Hb. However, there was no significant difference between the gr oups for 1-nitropyrene and 2-nitrofluorene supporting the conclusion that b oth are widespread environmental contaminants resulting in significant back ground exposures. A significant difference on a group from individuals from urban and rural areas was found only if all five adducts were added, this may indicate an additional exposure from traffic. The new specific nitro-PA H Hb adducts are proposed to be used as biomarkers to trace the sources and to identify above-background exposures. (C) 1999 Elsevier Science B.V. All rights reserved.