Polycyclic aromatic hydrocarbons (PAHs), of which benzo [a] pyrene is the most commonly
studied and measured, are formed by the incomplete combustion of organic matter. They are
widely distributed in the environment and human exposure to them is unavoidable. A
number of them, such as benzo [a] pyrene, are carcinogenic and mutagenic, and they are
widely believed to make a substantial contribution to the overall burden of cancer in
humans. Their presence in the environment is reflected in their presence at detectable levels …