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1F - QSAR (TUP/55) Influence of bioavailability and uncertainty on ranking of hazard and QSARs for toxicity towards terrestrial organisms. Thomsen, Marianne1, Borgen Sørensen, Peter1, Fauser, Patrik1, Scott-Fordsmand, Janeck2, 1 National Environmental Research Institute, Department of Policy Analysis, DK-4000, Roskilde, Denmark2 National Environmental Research Institute, Department of Terrestrial Ecology, DK-4000, Roskilde, Denmark ABSTRACT- The ranking of hazard potential for oil-tar polluted soils is investigated based on three common soil organisms, and three different endpoints. The chemical profile consists of PAHs as well as N, S, and O-heteroatom analogues of the PAHs. The sensitivity in the ranking of the potential hazard posed the individual oil-tar components, due to intra-species sensitivity and inter-species sensitivity quantified through endpoints at juvenile and adult life-stages, respectively, have been investigated. The probability of the ranking of the individual PAHs in quantified by implementing 1) uncertainty regarding dose-response curve-fitting, 2) influence of different exposure pathways, i.e. bioavailability, for different species. In parallel, QSARs for predicting the toxicity for the three soil organisms based on molecular descriptors as well as descriptors quantifying the atomic charge distribution has been analysed. Monte Carlo approaches for quantifying the significance of extractable information concerning both the ranking of hazard of PAHs due to toxicity and possible patterns in structure-activity has been performed. Alternative ranking approaches for prioritising the need for re-mediation activities of oil-tar polluted soils based on measured toxicity data as well as QSAR derived descriptors are presented. Key words: Ranking, oil-tar components, QSAR, terrestrial toxicity |
