A survey of solvent was conducted for 196 unit work areas in 95 plants in 1994 to 1996 in Hiroshima Prefecture, Japan. The survey had been repeated every 6 months (i.e., twice a year) during the 3-year period. Sampling and analysis of the solvent vapors were carried out after national protocols set by the regulation. Toluene was most frequently detected regardless of the type of solvent work (except for degreasing), whereas the second-and the third-most common solvents varied depending on the type of solvent works. Among chlorinated hydrocarbon solvents for degreasing, dichloromethane was most widely used. Solvent concentrations were generally low as none of the median concentrations exceeded corresponding Administrative Control Levels set by the regulation, either individually or even when the assumption of additiveness was applied. Among the 1176 cases analyzed, 80% of the unit work areas were evaluated as adequate (i.e., classified as Class I). Furthermore, about 57% stayed in Class I throughout the 3 years, suggesting that solvent exposure conditions were generally quite stable. In regulatory evaluation by classification, A-sampling was decisive in most cases, whereas the role of B-sampling was limited.

Separate Determination by Gas‐Chromatography of Dimethylformamide, Dimethylacetamide, Monomethylformamide and Monomethylacetamide in Urine for Biological Monitoring: Toshio Kawai, et al. Osaka Occupational Health Service Center—A gaschromatographic method is developed, which allows simultaneous determination of N,N‐dimethylformamide (DMF) and N,N‐dimethylacetamide (DMA), as well as their metabolites of N‐monomethylformamide (MMF) and N‐monomethylacetamide (MMA), respectively. Quantitative heat decomposition of N‐hydrcxymethyl‐N‐methylacetamide to N‐monomethylacetamide required an injection port temperature of 225°C or above, similar to the case of conversion from N‐hydroxymethyl‐N‐methylformamide to N‐monomethylformamide. Analysis of urine samples from workers simultaneously exposed to DMF and DMA showed that the separation of small peaks for unidentified materials (which were detected in some urine samples) from that of DMF and DMA was achieved only on a 60 m‐long DB‐1071 column (and not on a 30 m‐long one). The analysis of urine samples from 27 exposed workers showed that both DMF and DMA, in addition to MMF and MMA, were excreted in urine at measurable concentrations. There was a significant correlation between MMF and DMF, and between MMA and DMA; the ratio was about 0.02 to 0.03 for both DMF/MMF and DMA/MMA.

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.

Diffusive sampling with carbon cloth as an adsorbent can be applied to ambient air monitoring of exposure to 1-butanol. Urinalysis for 1-butanol after hydrolysis is sensitive enough to detect occupational 1-butanol vapour exposure at 3 ppm.