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(085) Relevance of PAH's exposure assessment by combined in vitro and in vivo assays. Gilbin, Rodolphe1, Gomez, Elena1, Fenet, Helene2, Casellas, Claude1, 1 2 ABSTRACT- Polycyclic aromatic hydrocarbons (PAH's) are common pollutants in the environment. Since several PAH's are toxic and carcinogenic, their eventual effects in river organisms are topics of environmental concern. A relevant evaluation of exposure is the first step to a risk assessment. PAH's are lipopholic compounds and tend to accumulate in sediments. During PAH exposure fish rapidly metabolise them and excrete metabolites through the bile. The phase I enzyme, measured as EROD activity, is also induced. Thus, fish bile fluorescence and EROD activity can be used as biomarkers of PAH's exposure. This specific response on fish need to be reconsidered in a multipollution context therefore to be compared with global toxic effects, i.e. on in-vitro bioassays with other organisms such as bacteria (luminescence inhibition on Vibrio fisheri) and algae (growth and metabolic inhibitions on Selenastrum capricornutum). The objective of this study was to propose a biomonitoring protocol of PAH's impact assessment in aquatic environment. Bile fluorescence and EROD activity were studied in fish held in cages during two weeks, in a polluted site and in a reference one. PAH's sediments concentrations were measured in each site. Bile fluorescence and EROD activity were significantly higher in eels caged in the polluted area as compared to the ones caged in the control area. Results were compared to toxic effects (EC50) observed on in-vitro bioassays. These preliminary data suggest that using combined markers allows a better interpretation of the potential impact of the exposure to PAH's in a multipollution context. Key words: PAH's, bile flourescence, EROD, EC50 |
