Diffusive sampling and biological monitoring of 2-bromopropane

The possibilities to apply personal ambient air monitoring by diffusive sampling and biological exposure monitoring by urinalysis for 2-bromopropane or its metabolites were explored. The abilities of carbon cloth to adsorb 2-bromopropane was examined by experimental vapor exposure followed by solvent extraction and FID-GC. Urine from factory workers and rats exposed to 2-bromopropane were analyzed for 2-bromopropane, acetone and isopropyl alcohol by FID-GC, and for bromide ion by ECD-GC after chemical methylation. Carbon cloth adsorbed 2-bromopropane in a manner linearly related to exposures up to 1500 mg/m3 and to 8 h. The adsorption could quantitatively detect a 15 min peak exposure at 3,000 mg/m3. In rat experiments, analyses of urine samples collected over a 4-h period after termination of a 4-h exposure to 2-bromopropane at 500, 1,000 or 1,500 mg/m3 showed that acetone and bromide ion were excreted dose-dependently. Essentially, no 2-bromopropane or isopropyl alcohol was detected. When the analytical methods were applied to urine samples from 5 male workers exposed to 2-bromopropane at a low level (3 mg/m3 as a geometric mean), acetone and bromide ion levels were within respective normal ranges in four cases, but were higher than the upper limits of the normal ranges in the fifth case of a foreman who probably had the highest exposure. Thus, diffusive sampling is applicable to monitor exposure to 2-bromopropane. Urinalysis for acetone and bromide ion in combination appears to be a promising selective tool for biological monitoring of occupational exposure to 2-bromopropane.