INCREASES IN POLYCYCLIC AROMATIC HYDROCARBON CONTENT AND MUTAGENICITY IN A CUTTING FLUID AS A CONSEQUENCE OF ITS USE

The aim of this study was to evaluate the relationships between the length of time a cutting fluid was used, its content in polycyclic aromatic hvdrocarbons (PAHs) and its mutagenic potential. The PAH concentrations were determined by means of a high-resolution gas chromatograph-mass spectrometer in samples of new cutting fluid and in samples used for 3, 6 and 9 months. The following PAHs were measured: phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene + triphenylene, benzo[e]pyrene, benzo[a]pyrene and perylene. Mutagenicitiy assays were carried out on the aforementioned samples using the Ames test. Salmonella typhimurium TA98 was used as an indicator to show up mutagens capable of inducing frame-shift genetic changes, and Escherichia coli WP2 uvrA was used as an indicator to detect mutagens capable of inducing base pair genetic changes. The mutagenic tests were carried out with and without microsomial activation, using 1:1, 1:10, 1:20 and 1:50 dilutions of cutting fluid samples. An increase in the concentrations of total PAHs over time was observed in the samples of cutting fluid used for 3, 6 and 9 months. The highest percentage increase in PAH concentrations was observed in the 6-month-old sample (10 times the initial concentration, from 45 to 411.8 mug of oil). None of the samples were mutagenic to S. typhimurium without metabolic activation or to E. coli with and without metabolic activation. All samples except for the 1:1 diluted sample showed moderate but significant mutagenic activity in the S. typhimurium test with metabolic activation. Mutagenicity rose to its highest levels (similar to those observed with the mutagenic compound 2-acetylaminofluorene, which was used as a positive control) in the 9-month-old sample and in the 6-month-old 1:20 and 1:50 diluted sample. This study shows an increase in the PAH concentrations and mutagenicity of cutting fluids following prolonged use. In order to minimize the risk caused by such an increase in PAH content, it is recommended that the cutting fluid be changed at least every 6 months.