Aromatic hydrocarbons – carcinogenicity and toxicity
Most polynuclear hydrocarbons are carcinogenic in nature. Polynuclear hydrocarbons contain two or more benzene rings fused together. These are also called polycyclic aromatic compounds. For example, naphthalene contains two benzene rings fused together. Other common examples are anthracene, phenanthracene, etc. the major source of these polynuclear hydrocarbons is coal tar. The isomeric monosubstituted naphthalenes are differentiated into α and β –naphthalenes. Naphthalene and other polynuclear aromatic hydrocarbons show many of the chemical properties similar to benzene. The volatile arenes are highly inflammable and burn with a yellow sooty flame. Many of these polynuclear aromatic hydrocarbons are toxic and some are carcinogenic let us discuss: It has been observed that the people who work under prolonged exposure to coal tar tends to suffer from skin cancer. A group of British chemists has studied that high boiling fluorescent fraction of coal tar produces cancer. The major component of this fraction was found to be 1,2-benzanthracene.
Later researches have shown that many other polynuclear hydrocarbons such as 3-methylcholanthracene, 1,2-benzpyrene, 9,10-dimethyl-1,2-benzanthracene, etc. are carcinogenic in nature.