Résumé
Polycyclic aromatic hydrocarbons (PAHs) are common pollutants in the environment. Since several PAHs and their metabolites are toxic and carcinogenic, their eventual effects in river organisms are topics of environmental concern. PAH are rapidly metabolized in fish and metabolites are excreted through the bile. Fish bile fluorescence has been proposed as biomarker for biomonitoring oil spills (1). Synchronous fluorimetric spectrometry (SFS) was used to estimate the exposure of fish to PAHs. This technique (2) has the advantage of being simple, rapid and cost-efficient and it is directly applied to the bile without previous hydrolysis and extraction steps. Bile fluorescence was studied in fish (eels) held in cages for two weeks, in a polluted site and in a reference site. Bile fluorescence was significantly higher in eels caged in the polluted area, as compared tothe ones caged in the control area (Fig. 1). A recovery from exposure occurred when the exposed fishes were moved to the reference site. The levels of bile fluorescence declined and by day 14 reached the levels observed in eels caged in the reference site.The SFS method is adapted to estimate the PAHs pollution; however, it is inaccurate for an identification of the different metabolites. We therefore developed a highperformance liquid chromatography/fluorescence detection method (HPLC/FD). HPLC/FD allowed the separation and identification of different metabolites, such as 2-OH-naphthalene, 1-OH-phenanthrene, 1-OH-pyrene, 1-OH chrysene and 3-OH-benzo(a)pyrene (Fig. 2). It wasapplied to identify and quantify PAH metabolites present in the bile of fish after two different exposures: dispersed crude oil and contaminated sediments.The exposure to contaminated sediments was confirmed by the presence of all the studied metabolites. In the bile of fish exposed to dispersed crude oil, the PAHs metabolites of high molecular levels were not found (1OH- chrysene and 3 OH-benzo(a)pyrene).These preliminary results suggest that fish bile fluorescence can be used as a biomarker of fish exposureto PAHs; the detection of specific metabolites with a HPLC/fluorescence detection method would allow to define the source of pollutants (combustion or oil hydrocarbons).