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1F - QSAR (TUP/56) Identification of PBT profile of chemicals accounting for their metabolism. Mekenyan, Ovanes1, Pavlov, Todor1, Dimitrov, Sabcho1, Veith, Gilman2, 1 Laboratory of Mathematical Chemistry, University “Prof. As. Zlatarov”, Bourgas, Bulgaria, Bulgaria2 U.S.EPA, Mid-Continent Ecology Division, 6201 Congdon Blvd, Duluth, MN 55804, USA ABSTRACT- Since initiatives of the UN-ECE in 1992 the persistent organic pollutants (POPs) have gained a lot of attention from the scientific and governmental organizations. In order to be identified as possible POPs candidates have to meet several criteria for potential long-range atmospheric transport, toxicity, persistence and bioaccumulation. Several workshops were devoted on the selection of an efficient identification scheme for persistence (P), toxicity (T) and bioaccumulation (B) potential. Although the role of biodegradation has been emphasized, no one of the existing classification algorithms has taken into account the environmental impact of the generated metabolites. This work describes a classification method and respective software for assessing PBT profile, accounting for the metabolic transformations of parent chemicals. The system allows PBT classification not only of parent chemicals but also of their stable metabolites. A library of metabolic simulators is used to assess the rate of biodegradation. The evaluation of bioaccumulation potential is based on non-linear BCF model on fish defined within a large range of hydrophobicity variation. Molecular flexibility and steric parameters are also taken into account in assessing BCF. A library of acute (e.g., aquatic, phototoxicity, etc.) and chronic (e.g., mutagenicity, receptor mediated, etc.) toxic endpoints is used to characterize toxic profile of chemicals and their metabolites. Key words: PBT profile, POP, metabolism, risk assessment |
