Repositori URV

Identifier: TDX:481

Handle: https://hdl.handle.net/20.500.11797/TDX481

Authors:
Fuster Camp, Gerard

Abstract:
Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are ubitiquous organic pollutants. They are generated in small quantities as by-products of several chemical and combustion processes. The number and position of chlorine atoms at the benzene rings of PCDD/Fs molecules lead to 75 PCDDs individual compounds or congeners and 135 PCDFs congeners. Their high lypophilic character is the cause of their tedency to accumulate in soils, sediments, plants, animal and human adipose tissue. From several studies about impacts on humans to the congener 2,3,7,8-TCDD, the American Insitute of Medicine has described that there is evidence that exposure to this compound through the feeding chain and inhalation induces in humans several symptoms of toxicity: cloracne, systemic and neropsyquic. Respect to carcinogenic effects, the International Agency of Research on Cancer (IARC) reclassified in 1997 this congener from the group II of its classification: 'a probable carcinogenic agent in humans' to the group I: 'known carcinogenic agent in humans'. Concentration of a mixture of congeners is the result of adding up concentrations of each congener, and it is expressed in international toxic equivalents of the 2,3,7,8-TCDD (I-TEQ), which gives a toxic potential of the mixture. It is obtained from the toxic equivalent factors (TEF).During the last decade there has been an important development of methodologies which have searched to be an efficient tool within environmental management. Damage Function methods are the most usual. These use the variable concentration as the way to fix the impact by pollution. Nevertheless, the present study has looked to be an alternative, by adding the variable flow of pollutants as a tool for its calculations. Then, it has been developed and app