1. Introduction
The term 'polycyclic aromatic hydrocarbons' (PAHs) commonly refers to a large class of organic compounds
containing two or more fused aromatic rings made up of carbon and hydrogen atoms. PAHs are formed and
released during incomplete combustion or pyrolysis (burning) of organic matter such as waste or food, during
industrial processes and other human activities. PAHs are also formed in natural processes, such as
carbonisation. The general characteristics common to the class are high melting and boiling points, low
vapour pressure, and very low water solubility which tends to decrease with increasing molecular mass. PAHs
are soluble in many organic solvents and are therefore lipophilic (soluble in fat).
Figure 1 shows the structure of ben