Biologic monitoring for dimethylacetamide: measurement for 4 consecutive weeks in a workplace

The determination of urinary N-monomethylacetamide (MMAC) in the end-of-shift urine sample was used to monitor exposure to dimethylacetamide (DMAC). Five workers were observed followed for 4 consecutive weeks. Airborne DMAC appeared to account for the greatest amount of urinary MMAC detected and, at the exposure concentrations encountered (0.5 to 2 ppm), a relationship of 10 ppm urinary MMAC for each 1 ppm DMAC inhaled was observed. Interindividual variation was small and no evidence of build-up in MMAC urinary levels was seen in these subjects. Mean airborne DMAC concentrations were somewhat higher by the end of the week, but the magnitude was such that the differences were not statistically significant. It is concluded that changes in DMAC exposures can be quantitatively reflected by urinary MMAC.