Toxicity of polycyclic aromatic hydrocarbons (PAHs) in diesel exhausts

The paper presents results of analysis of Polycyclic Aromatic Hydrocarbons (PAHs) concentration and toxicity emitted from 1,9 TDI self-ignition. Because of unstable parameters of self-ignition engine work (pressure and temperature jumps), PAHs were extracted from two phases: gas phase and solid phase (particle matter - PM). A chromatographic method (Capillary gas Chromatography) of polycyclic aromatic hydrocarbons identification and analysis, because of their low level of concentration in exhaust gases, needed to be supported by sample purification and enrichment stages. Calibration of the chromatograph was made by attested mixture of 16 model samples (according to EPA, USA). Two different methods for toxicity estimation was used in this researches. The authors used relative carcinogenic coefficients (RCC) which was determined by Nisbet and LaGoy for individual polycyclic aromatic hydrocarbons in relation to benzo(a)pirene. Samples consist PAHs was also tested for cytotoxicity in standardized cell-culture system (human cell line A549, mouse fibroblasts line cell L929). Cell growth, cell morphology and cell viability were used as parameters to determine the cytotoxicity of the materials. The measure the lethality effect on cells was determined spectrophotometrically with the use of a mitochondrial enzyme activity assay for mitochondrial succinate dehydrogenase activity by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT assay). Cells were exposed to the biomaterials for 24, 72 and 120 h. The results of in vitro tests are discussible. A lach of correlation between toxicity measurement methods which was used in these researches was observed.