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(76-03) Measuring bioaccumulation of polycyclic aromatic hydrocarbons by aquatic organisms using spectrofluorimetry: method and applications. Gourlay, Catherine*,1, Miège, Cécile2, Garric, Jeanne2, Tusseau-Vuillemin, Marie-Hélène3, Mouchel, Jean-Marie1, 1 CEREVE, Marne La Vallée, France2 Cemagref, Lyon, France3 Cemagref, Antony, France ABSTRACT- A direct spectrofluorimetric method was developed in order to monitor the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms. Bioaccumulation of fluoranthene and benzo[a]pyrene in Daphnia magna was first studied. After exposure to one PAH for 2 to 24 hours, daphnids were put in an organic solvent, sonicated and filtrated. In a first place, the fluorescence spectrum of the filtrate was recorded. Results were compared with chromatographic analysis (HPLC-fluorescence detection) of the same pools of organisms. In fluoranthene experiments, the fluorescence peak of daphnids extract spectrum was linearly related to fluoranthene content as measured with HPLC. In benzo[a]pyrene experiments, shifts in the fluorescence spectrum were progressively observed when the exposure time increased, indicating that other fluorescent compounds appeared in the sample. A linear regression involving fluorescence intensities at two different wavelengths was necessary for a satisfactory correlation with HPLC measurements. In a second place, water was added to daphnids extract and the solution was shaken. After separation the fluorescence spectrum of each phase was recorded. No or very few hydrophilic fluoranthene metabolites were isolated in water, whereas increasing benzo[a]pyrene metabolites were observed in the aqueous phase while the exposure time increased. A simple and rapid estimation of PAHs in aquatic organisms is feasible with this method. More interestingly, it is possible to simply monitor metabolism of PAH. It has been applied to study (i) the effect of dissolved organic matter on the bioaccumulation of PAHs by daphnids and (ii) the monitoring of benzo[a]pyrene metabolism in fish eggs and larvae. Key words: polycyclic aromatic hydrocarbons, bioaccumulation, metabolism, spectrofluorimetry |
