Carcinogenicity and Toxicity

· Benzene and polynuclear hydrocarbons containing more than two benzene rings fused together are toxic and said to possess cancer producing (carcinogenic) property.

· Such polynuclear hydrocarbons are formed on incomplete combustion of organic materials like tobacco, coal and petroleum.

· They enter into human body and undergo various biochemical reactions and finally damage DNA and cause cancer.

Ex: 1, 2 -benzpyrene; 9, 10-dimethyl-1, 2-benzanthracene.

It is found that the number and position of certain groups such as methyl, hydroxide, cyanide and methoxy in these compounds give rise to carcinogenic tendencies.