Polycyclic Aromatic Hydrocarbons and Azaaromatic Compounds

AbstractPolycyclic aromatic hydrocarbons (PAHs) are moderately reactive, but undergo photochemical degradation in the atmosphere, and are widely used as chemical raw materials. Aromatic hydrocarbons cause local irritation and changes in endothelial cell permeability and are absorbed rapidly. Accumulation of aromatic hydrocarbons in marine animals occurs to a greater extent and retention is longer compared to alkanes. Toxicity of polynuclear aromatics has been reported comprehensively. It has been reported that exposure to a variety of complex mixtures containing these chemicals, such as soot, coal tar and pitch, mineral oils, coal gasification residues, and cigarette smoke has historically been associated with induction of cancer. Naphthalene causes cataracts in the eyes of experimental animals. Its vapors may cause severe systemic injury. Alkylbenzenes are readily aspirated and produce instant death via cardiac arrest and respiratory paralysis. In general, the acute toxicity of alkylbenzenes is higher for toluene than that for benzene and decreases further with increasing chain length of the substituent, except for highly branched C8to C18derivatives. Polycyclic aromatic hydrocarbons are metabolized through epoxides and hydroxides and are excreted as conjugates.