RESUMO
Induction of ethoxyresorufin-O-deethylase (EROD) activity and porphyrin accumulation shows different structure-activity relationships for different polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Interactions between the two responses can strongly influence the induction and activity of EROD. The results support the conclusion that there are nonadditive interactions between nondioxin-like PCBs and dioxin-like compounds. The interaction between EROD activity and the porphyrin biosynthesis makes the prerequisite of additivity in the toxic equivalency factor concept for environmental mixtures highly spurious. Inhibition of EROD activity caused by non-dioxin like compounds could have a significant impact on the value of EROD activity as a biomarker in the present methods of risk assessment for these compounds.
RESUMO
A scientific evaluation was made of the mechanisms of action of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls. Distinction is made between the aryl-hydrocarbon (Ah) receptor-mediated and non-Ah receptor-mediated toxic responses. Special attention is paid to the applicability of the toxic equivalency factor (TEF) concept.
Assuntos
Benzofuranos/efeitos adversos , Poluentes Ambientais/efeitos adversos , Bifenilos Policlorados/efeitos adversos , Dibenzodioxinas Policloradas/análogos & derivados , Polímeros/efeitos adversos , Animais , Benzofuranos/metabolismo , Benzofuranos/toxicidade , Ingestão de Alimentos , Exposição Ambiental , Poluentes Ambientais/metabolismo , Poluentes Ambientais/toxicidade , Humanos , Exposição Ocupacional , Bifenilos Policlorados/metabolismo , Bifenilos Policlorados/toxicidade , Dibenzodioxinas Policloradas/efeitos adversos , Dibenzodioxinas Policloradas/metabolismo , Dibenzodioxinas Policloradas/toxicidade , Polímeros/metabolismo , Polímeros/toxicidade , Receptores de Hidrocarboneto Arílico , Receptores de Droga/metabolismo , Gestão de Riscos , Distribuição TecidualRESUMO
Fires, explosions and other accidents in polychlorinated biphenyl (PCB)-filled equipment can result in possible exposure of firemen, cleaning personnel and regular workers. Inhalation, dermal exposure and ingestion are the possible routes of exposure. An indirect assessment of the exposure can be made by analyses of wipes, air and water samples and clothes. A direct assessment of exposure can be made by analyses of blood samples, adipose and other tissue samples, feces and bile.