Comparison of internal dose measures of solvents in breath, blood and urine and genotoxic changes in aircraft maintenance personnel

Solvents and fuels are in widespread use both in civilian and military popu lations. 1,1,1-trichloroethane (TCA) xylene, toluene, methyl ethyl ketone ( MEK) and methylene chloride are found in a variety of compounds including d egreasing agents, paints, coatings, pesticides and paint strippers. Toluene and xylene are also found in fuels, which are complex mixtures of hundreds of agents. The purpose of this investigation was twofold. The first was to determine the optimum medium to measure internal close of solvents compari ng blood, urine and breath. The second was to determine if low level exposu res were associated with genotoxic changes after a short-term exposure of f ifteen or thirty weeks. To accomplish the first goal a pilot study was init iated involving eight volunteers who worked in aircraft maintenance includi ng sheetmetal, painting and assembly mechanic jobs. Industrial hygiene meas urements were evaluated over 30 working days. Breath, blood and a 24-hour u rine sample were collected twice to compare internal dose parameters. To ac hieve the second Real, 58 newly hired subjects ware monitored prior to expo sure and over 30 weeks to determine if there were genotoxic changes as a re sult of solvent and/or fuel exposure as measured by sister chromatid exchan ges (SCEs) and micronuclei (MN). Exposure groups included workers involved in sheetmetal (fuel cell) activities, painting, fueling operations and flig ht line. Results of the pilot study demonstrated that industrial hygiene air samples and internal breath measures taken an the same day were highly correlated far measuring TCA (r=0.93) and toluene (r=0.90) but was not as well correla ted for the other compounds. Breath measures were more sensitive for measur ing low level exposure than were either analytes in blood or 24-hour urine samples; these latter two measures were usually below the limit of detectio n. A small but statistically significant increase in the frequency of SCEs occurred after 30 weeks of exposure for sheet metal workers (p=0.003) and f or painters (p=0.05). The MN frequency in the sheet metal workers initially showed a significant increase by 15 weeks, but by 30 weeks had decreased C hance occurrence of exposures to other occupational or non-occupational age nts can not be eliminated as a cause of the genotoxic results since between 58 and 93 total analytes could be found in the breath of some aircraft mai ntenance personnel.