Genotoxic changes after low-level solvent and fuel exposure on aircraft maintenance personnel

Mutagenesis, Jul 1997

Individuals may be exposed to solvensudhirt mixtures and fuel either at work or home, through air, water and food contamination. Few studies have addressed the genotoxic effects of mixed, low-level exposure to fuel and solvent. This was an optimally designed study where each subject was sampled prior to exposure and after 15 and 30 weeks while exposed, in a repeated measures design with each subject serving as his own control. Fifty men aged between 18 and 50, working on aircraft equipment operation and maintenance at a military installation were included. Eight unexposed men were concurrently sampled. Sisterchromatid exchanges (SCE) and micronuclei (MN) frequency were measured in conjunction with air sampling and expired breath analysis for jet fuel (JP-4), 1,1,1-trichloroethane, methyl ethyl ketone, xylenes, toluene and methylene chloride. Exposure levels measured by industrial hygiene were very low (all means <6 p.p.m.), <10% of the OSHA standard. Expired breath levels were also low, <25 p.p.b. A small but statistically significant increase in the frequency of SCE occurred after 30 weeks of exposure for sheet metal workers (P = 0.003) and for painters (P = 0.05). The MN frequency in the sheet metal workers initially showed a statistically significant increase, but by 30 weeks had decreased. Cigarette smoking, alcohol and caffeine use were not associated with changes from baseline for either MN or SCE. Smokers, however, had significantly higher values of SCEs at baseline than did nonsmokers. In summary, these findings suggest that small increases in SCEs in particular, may serve as a sensitive biologic indicator of low level hydrocarbon exposure in as much as statistically significant changes occurred in the highest exposed groups but not in the low or no exposure groups. Chance occurrence or exposures to other occupational or non-occupational agents cannot be eliminated as a cause of the study findings.

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Genotoxic changes after low-level solvent and fuel exposure on aircraft maintenance personnel

Grace Kawas Lemasters 0 Gordon K.Livingston 0 James E.Lockey 0 Donna M.Olsen 0 Rakesh Shukla 0 George New 0 Sherry G.Selevan 0 James H.Yiin 0 0 University of Cincinnati , 231 Bethesda Avenue, Cincinnati, OH 45267- 0182 , USA 'To whom correspondence should be addressed - Individuals may be exposed to solvent mixtures and fuel either at work or home, through air, water and food contamination. Few studies have addressed the genotoxic effects of mixed, low-level exposure to fuel and solvent. This was an optimally designed study where each subject was sampled prior to exposure and after 15 and 30 weeks while exposed, in a repeated measures design with each subject serving as his own control. Fifty men aged between 18 and 50, working on aircraft equipment operation and maintenance at a military installation were included. Eight unexposed men were concurrently sampled. Sisterchromatid exchanges (SCE) and micronuclei (MN) frequency were measured in conjunction with air sampling and expired breath analysis for jet fuel (JP-4), 1,1,1trichloroethane, methyl ethyl ketone, xylenes, toluene and methylene chloride. Exposure levels measured by industrial hygiene were very low (all means <6 p.p.m.), <10% of the OSHA standard. Expired breath levels were also low, <25 p.p.b. A small but statistically significant increase in the frequency of SCE occurred after 30 weeks of exposure for sheet metal workers (P = 0.003) and for painters (P = 0.05). The MN frequency in the sheet metal workers initially showed a statistically significant increase, but by 30 weeks had decreased. Cigarette smoking, alcohol and caffeine use were not associated with changes from baseline for either MN or SCE. Smokers, however, had significantly higher values of SCEs at baseline than did nonsmokers. In summary, these findings suggest that small increases in SCEs in particular, may serve as a sensitive biologic indicator of low level hydrocarbon exposure in as much as statistically significant changes occurred in the highest exposed groups but not in the low or no exposure groups. Chance occurrence or exposures to other occupational or non-occupational agents cannot be eliminated as a cause of the study findings. Introduction Most people are exposed to solvent mixtures and/or fuels either at work, home or through air, water and food contamination. 1,1,1-Trichloroethane (TCA), xylene, toluene, methyl ethyl ketone (MEK) and methylene chloride are found in a variety of compounds including solvents, paints and gasoline. The widespread use of mese chemicals to clean or degrease parts also requires the disposal of large volumes each year. Fuels and benzene (as a fuel component) also represent an intermittent, ubiquitous low-level source of exposure for the general population. The US Environmental Protection Agency estimates uiat 3.6X108 gallons of gasoline are released as vapors into the atmosphere. Automobile refueling at retail service stations is thought to account for ~40% of reported gasoline vapor emissions (Mehlman, 1992). In the US, ~70% of gasoline is dispensed from self-service pumps causing vapor exposure to ~110 million people (Maklan et al, 1987). Results of population studies of solvent and fuel exposure and their effect on the frequency of sister chromatid exchange (SCE) and micronuclei (MN) have been mixed due to the variety of exposures studied (Van Hummelen et al, 1994; Yager et al, 1993; Laurent et al, 1993; McDiarmid et al, 1995; Hallier et al, 1993; Hallier et al, 1994; Sardas et al, 1994; Richer et al. 1993; Suruda et al, 1993). For example, continuous, low-dose benzene exposure increased SCE frequency (Major et al, 1994), automobile painters with mixed solvent exposure had significantly higher SCEs (Sardas et al, 1994), and inhabitants of a village in Belgium located at the edge of an industrial waste dump showed significantly higher SCE rates than non-residents (Laurent et al, 1993). A controlled exposure experiment using either single exposures to xylene and toluene, or the two in combination, however, showed no significant genotoxic effects (Richer et al, 1993). In addition, a study of US mortuary science students comparing MN frequencies prior to their first exposure to embalming fluid (formaldehyde) and again after 90 days of exposure, found an increase of MN from 5.0 to 6.4 MN/1000, while SCEs decreased by 7.5% (Suruda et al, 1993). A study of plastics workers exposed to styrene, another hydrocarbon, found that MN in both the exposed and unexposed populations averaged between 3.3 and 4.8, respectively (Van Hummelen et al, 1994). Conversely, a study in Germany of styrene and dichloromethane exposure demonstrated a significant difference between mean MN frequency in the exposed population of 35.1 compared to the unexposed mean of 14.3 (Tates etal, 1994). Smoking is known to increase the frequency of SCE. A study conducted by Livingston and Fineman (1983) compared 24 smokers with 24 sex and age matched controls who had never smo (...truncated)


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Grace Kawas Lemasters, Gordon K. Livingston, James E. Lockey, Donna M. Olsen, Rakesh Shukla, George New, Sherry G. Selevan, James H. Yiin. Genotoxic changes after low-level solvent and fuel exposure on aircraft maintenance personnel, Mutagenesis, 1997, pp. 237-243, 12/4, DOI: 10.1093/mutage/12.4.237