title: Evaluation of urinary metabolites of 1-nitropyrene as biomarkers for exposure to diesel exhaust in taxi drivers of Shenyang, China.
abstract: Diesel exhaust (DE) is a significant contributor to the toxicity associated with particulate matter (PM). 1-Nitropyrene (1-NP) has been used as a molecular marker for DE, and the urinary metabolites of 1-NP have been proposed as biomarkers for exposure to DE. In this study, several urinary 1-NP metabolites were evaluated for their utility as markers of short-term exposures to DE. The study population was a cohort of 24 taxi drivers from Shenyang, China, who submitted urine samples collected before, after, and the next morning following their workshifts. The urinary metabolites studied were isomers of hydroxy-1-nitropyrene (3-, 6-, 8- OHNPs) and hydroxy-N-acetyl-1-aminopyrene (3-,6-, 8-OHNAAPs). Exposure to DE was estimated based on exposure to 1-NP in air samples collected during and after the driver's workshift; 6- and 8-OHNP, and 8-OHNAAP were consistently detected in the drivers' urine. Concentrations of the metabolites in the taxi drivers' urine were greater than metabolite levels previously reported in non-occupationally exposed subjects; however no associations were observed between subject-specific exposures to 1-NP and urinary metabolites measured at the end of the workshift or in the next morning void. Significant autocorrelation was observed in metabolite levels in successive urine samples, from which half-lives for urinary elimination of ~10-12 h were estimated. These observations suggest that, in an occupational setting, urinary 1-NP metabolites may be more suitable as markers of ongoing exposure (timescales of several days) rather than indicators of acute exposure associated with single workshifts.
authors.affiliation: Center for Urban Waters, University of Washington-Tacoma, Tacoma, WA, USA.
authors.forename: Justin P
authors.initials: JP
authors.lastname: Miller-Schulze
authors.forename: Michael
authors.initials: M
authors.lastname: Paulsen
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kameda
authors.forename: Akira
authors.initials: A
authors.lastname: Toriba
authors.forename: Ning
authors.initials: N
authors.lastname: Tang
authors.forename: Kenji
authors.initials: K
authors.lastname: Tamura
authors.forename: Lijun
authors.initials: L
authors.lastname: Dong
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhang
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Hayakawa
authors.forename: Michael G
authors.initials: MG
authors.lastname: Yost
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Simpson
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine*; D002681:China; D002851:Chromatography, High Pressure Liquid; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D011721:Pyrenes / Q000652:urine*; D053719:Tandem Mass Spectrometry; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D011721:Pyrenes; D001335:Vehicle Emissions; C032668:1-nitropyrene