Biological monitoring of occupational exposure to 1-bromopropane by means of urinalysis for 1-bromopropane and bromide ion

The purposes of the present study are (1) to develop a sensitive analytical method to measure 1-bromopropane (1-BP) in urine, (2) to examine if 1-BP o r bromide ion (Br) in urine is a useful biomarker of exposure to 1-BP, and (3) to identify the lowest 1-BP exposure concentration the method thus esta blished can biomonitor. A factory survey was carried out on Friday, and 33 workers (all men) in cleaning and paintng workshops participated; each work er was equipped with a diffusive sampler (carbon cloth KF-1500 as an adsorb ent) to monitor 1-BP vapour for an 8-h shift, and offered a urine sample at the end of the shift for measurement of 1-BP and Br in urine. In addition, 10 non-exposed men offered urine samples as controls. The performance of t he carbon cloth diffusive sampler was examined to confirm that the sampler is suitable for monitoring time-weighted average 1-BP vapour exposure. A he ad-space GC technique was employed for analysis of 1-BP in urine, whereas B r in urine was analysed by ECD-GC after derivatization to methyl bromide. T he workers were exposed to vapours of seven other solvents (i.e. toluene, x ylenes, ethylbenzene, acetone, etc.) in addition to 1-BP vapour; the 1-BP v apour concentration was 1.4 ppm as GM and 28 ppm as the maximum. Multiple r egression analysis however showed that 1-BP was the only variable that infl uenced urinary 1-BP significantly. There was a close correlation between 1- BP in urine and 1-BP in air; the correlation coefficient. (r) was >0.9 with a narrow variation range, and the regression line passed very close to the origin so that 2 ppm 1-BP exposure can be readily biomonitored. The correl ation of Br in urine with 1-BP in air was also significant, but the r (abou t 0.7) was smaller than that for 1-BP, and the background Br level was also substantial (about 8 mg l(1)). Thus, it was concluded that 1-BP in end-of- shift urine is a reliable biomarker of occupational exposure to 1-BP vapour , and that Br in urine is less reliable.