Urinary methyl tert-butyl ether and benzene as biomarkers of exposure to urban traffic.
Methyl tert-butyl ether (MTBE) and benzene are added to gasoline to improve the combustion process and are found in the urban environment as a consequence of vehicular traffic. Herein we evaluate urinary MTBE (MTBE-U) and benzene (BEN-U) as biomarkers of exposure to urban traffic. Milan urban policemen (130 total) were investigated in May, July, October, and December for a total of 171 work shifts. Personal exposure to airborne benzene and carbon monoxide (CO), and atmospheric data, were measured during the work shift, while personal characteristics were collected by a questionnaire. A time/activity diary was completed by each subject during the work shift. Spot urine samples were obtained for the determination of MTBE-U and BEN-U. Median personal exposure to CO and airborne benzene were 3.3 mg/m(3) and 9.6 μg/m(3), respectively; median urinary levels in end-of-shift (ES) samples were 147 ng/L (MTBE-U) and 207 ng/L (BEN-U). The time spent on traffic duty at crossing was about 40% of work time. Multiple linear regression models, taking into account within-subject correlations, were applied to investigate the role of urban pollution, atmospheric conditions, job variables and personal characteristics on the level of biomarkers. MTBE-U was influenced by the month of sampling and positively correlated to the time spent in traffic guarding, CO exposure and atmospheric pressure, while negatively correlated to wind speed (R(2) for total model 0.63, P<0.001). BEN-U was influenced by the month and smoking habit, and positively correlated to urinary creatinine; moreover, an interaction between CO and smoking was found (R(2)=0.62, P<0.001). These results suggest that MTBE-U is a reliable marker for assessing urban traffic exposure, while BEN-U is determined mainly by personal characteristics.
Department of Occupational and Environmental Health, Università degli Studi di Milano and Department of Preventive Medicine, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
Laura
L
Campo
Andrea
A
Cattaneo
Dario
D
Consonni
Licia
L
Scibetta
Paolo
P
Costamagna
Domenico M
DM
Cavallo
Pier Alberto
PA
Bertazzi
Silvia
S
Fustinoni
D000328:Adult; D000393:Air Pollutants / Q000378:metabolism / Q000652:urine*; D001272:Atmosphere / Q000737:chemistry; D001554:Benzene / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism / Q000652:urine; D002947:Cities; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D016014:Linear Models; D008297:Male; D008738:Methyl Ethers / Q000652:urine*; D008875:Middle Aged; D014106:Tosylarginine Methyl Ester / Q000378:metabolism / Q000652:urine; D014186:Transportation / Q000706:statistics & numerical data; D001335:Vehicle Emissions / Q000032:analysis*; D055815:Young Adult
D000393:Air Pollutants; D015415:Biomarkers; D008738:Methyl Ethers; D001335:Vehicle Emissions; C043243:methyl tert-butyl ether; D014106:Tosylarginine Methyl Ester; D001554:Benzene