ABSTRACT
Within the large family of Persistent Organic Pollutants (POPs), organochlorine substances like polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are considered the most toxic and widespread compounds [1]. PCDD/Fs are commonly named dioxin, and are composed of a total number of 210 congeners, who’s the most toxic for humans and animals could be grouped in 17 congeners: 7 for PCDDs and 10 for PCDFs [2]. PCBs are known to be composed of a total of 209 congeners, but the most toxic ones are the co-planar PCBs, which are 12, and present a toxic behavior similar to PCDD/Fs; for this reason, these congeners are named dioxin-like PCBs. The exposure to such compounds has been object of important concern in the last decades [3], especially in the light of their health effects. Acute
toxicity does not represent the most important hazard; the primary risk is related to chronic exposures at lower concentrations. 2,3,7,8-TCDD, the most toxic PCDD/F congener, was classified as carcinogenic to humans by the International Agency for the Research on Cancer (IARC). This compound is the most known cancer promoter, since increased risks for lung cancer, soft-tissue sarcoma, non-Hodgkin lymphoma and other malignant neoplasms were reported in several cohort studies [4,5]. There is also clear evidence that PCBs cause cancer in animals, especially liver and thyroid neoplasms [6,7]. In addition, the results of a number of epidemiological studies raise concerns for the potential carcinogenicity of PCBs on humans [7]. For these reasons, the IARC classified PCBs in the Group 2A, as potential carcinogenic to humans [8].
