**2. Persistent organic pollutants**

Persistent organic pollutants (POPs) are chemicals that are resistant to degradation in the environment and biota, bioaccumulate and are toxic [8]. These contaminants include various lipophilic compounds, which accumulate primarily in lipid-containing tissues such as adipose tissue and move within the body attached to lipids and accumulate during life become a source of chronic internal exposure as they are released continuously from the adipose tissue to the circulation and vital organs with lipid content. POPs cover a variety of lipophilic chemicals resistant to environmental degradation that bioaccumulate in food webs and living organisms including humans [9]. Biomagnification is produced in humans when several orders of magnitude being higher than in the environment. Organochlorine pesticides such as DDT, lindane, chlordane, and hexachlorobenzene are typical examples of POPs. Other persistent organic pollutants are produced as industrial chemicals or by-products, including polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polybrominated diphenyl ethers [9].

On the other hand, polycyclic aromatic hydrocarbons (PAHs) are one of the main types of environmental pollutants that often occur during fuel combustion, and are widely distributed in our environment. The effects that these pollutants cause on human health, like POPs, are cause for concern since they can damage the nervous and endocrine systems, they can even become carcinogenic even in low concentrations [10, 11].
