Monitoring Acrylic Fiber Workers for Liver Toxicity and Exposure to Dimethylacetamide: 1. Assessing Exposure to Dimethylacetamide by Air and Biological Monitoring

• Published in: Journal of occupational and environmental medicine 1995-09, Vol.37 (9), p.1093-1101
• Main Authors: Spies, Gary J., Rhyne, Robert H., Evans, Roger A., Wetzel, Karin Emmonds, Ragland, Donna T., Turney, Houston G., Leet, Terry L., Oglesby, Jerry L.
• Format: Article
• Language: English
• Subjects: Acetamides - adverse effects; Acetamides - pharmacokinetics; Adult; Air Pollutants, Occupational - adverse effects; Air Pollutants, Occupational - pharmacokinetics; Chemical and Drug Induced Liver Injury - diagnosis; Chemical and Drug Induced Liver Injury - urine; Creatinine - urine; Environmental Monitoring; Feasibility Studies; Health risk assessment; Humans; Liver; Male; Maximum Allowable Concentration; Middle Aged; Occupational Diseases - chemically induced; Occupational Diseases - diagnosis; Occupational Diseases - urine; Occupational Exposure - adverse effects; Occupational hazards; ORIGINAL ARTICLES; Risk Factors; Solvents; Solvents - adverse effects; Solvents - pharmacokinetics; Textiles; Toxicity; Urinalysis
• ISSN: 1076-2752; 1536-5948
• DOI: 10.1097/00043764-199509000-00010

Worker exposure to N,N-dimethylacetamide (DMAC) in an acrylic fiber manufacturing facility was measured, over a 1-year study period, by full-shift (12 hours) personal air monitoring for DMAC and by biological monitoring for levels of DMAC, N-methylacetamide (MMAC), and acetamide in spot urine samples. Ninety-three of 127 male workers in seven job classifications the solution preparation and spinning departments of the plant were monitored on the second consecutive workday after at least 3 days off for the first 10 months of the study and on both the first and second days during the study's final 2 months. Postshift urinary MMAC levels were significantly correlated (P < .0001, r² = .54) with DMAC in air levels. An air level of 6.7 ppm 12-hour time-weighted average (TWA) corresponded to a urine MMAC level 62 mg/g creatinine in a postshift spot urine sample obtained after the second consecutive workday. To minimize exposure misclassification due to variability in the regression relationship, a level of 35 mg MMAC/g creatinine in a postshift spot urine sample was recommended as a biomonitoring index. Postshift urine MMAC levels did not appear to plateau at higher air levels, nor did it appear that the DMAC demethylation metabolic mechanisms became saturated at threshold limit value (TLV)-level air-exposure levels. Urine MMAC levels in postshift samples obtained the second workday appeared to be greater than levels in postshift first-day samples, but the number of days until this postshift level would plateau could not be determined from this study. A level of 35 mg MMAC/g creatinine in a postshift urine sample obtained after as many consecutive workdays as feasible appears to be an acceptable biomonitoring index of exposure to DMAC for workers completing a 12-hour shift.