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2J - TIE (TUP/133) CALUX assay-directed Toxicity Identification & Evaluation of Endocrine Disrupting Chemicals in sediment. Houtman, Corine1, Booij, Petra1, Swart, Cornelis1, Lamoree, Marja1, Legler, Juliette1, Brouwer, Abraham, 1 Institute for Environmental Studies, Amsterdam, The Netherlands, The Netherlands ABSTRACT- Nowadays, the presence of endocrine disrupting chemicals (EDCs) in the environment is a topic of great concern. Nevertheless, compounds responsible for estrogenic activity in e.g. sediment samples are still mainly unknown. In order to identify (unknown) EDCs in sediment, a Toxicity Identification and Evaluation (TIE) procedure is being developed in our laboratories. In this approach, Dioxin Responsive (DR-) and Estrogen Responsive (ER-) CALUX-assays (Chemical Activated Luciferase Gene Expression) are applied to assess total dioxin-like and estrogenic activity in the sample and to direct HPLC-fractionation according to log Kow and chemical analysis (with GC-MS) of active compounds. The method was applied first to a standard sediment sample. Fractionation resulted in almost complete separation of dioxin-like and estrogenic activities. Most estrogenic activity was found in a fraction of low log Kow (fraction log Kow 2-3), suggesting the presence of relatively polar estrogenic compounds in sediment. Natural estrogenic hormones possess log Kow values in the same range and would, if present in sediment, elute in the same fraction. Therefore, GC-MS techniques were used to assess the contribution of natural estrogens in the estrogenic activity observed. In accordance with chemical properties of known stable AhR agonists, dioxin-like activity in this sample was mainly found in the non-polar fraction. GC-MSD spectra of these fractions were deconvoluted using the automated mass spectral deconvolution and identification system AMDIS and compared to reference spectra in the NIST mass spectral database for tentative identification. The combination of CALUX assays with analytical separation and fractionation techniques is a promising tool for the elucidation of dioxin-like and estrogenic compounds in sediment samples. Key words: sediment toxicity, endocrine disruption, Toxicity Identification and Evaluation (TIE), bioassay |
