Thesis jointly supervised by ANSES (French Agency for Food, Environmental and Occupational Health & Safety), laboratory of Ploufragan in Plouzané. PhD jointly supervised by: Claire Quentel
Committee: Jean LAROCHE, François SICHEL, Thierry CAQUET, Stéphane LE FLOCH, Tristan RENAULT, GILLES SALVAT
Abstract: The ecotoxicity of hydrocarbons and pesticides, was investigated in adult fish at in vivo exposure concentrations similar to those found chronically in the natural environment. The sanitary status, i.e. the health status of fish, with regard to chemical pollution and physiological status, was evaluated in sea bass, Dicentrarchus labrax exposed to a mixture of hydrocarbons using the water soluble fraction of crude oil and in rainbow trout, Oncorhynchus mykiss, contaminated by an active substance present in pesticide, pendimethalin. The pollutant molecules were quantified both in the exposure water and the fish (muscle and bile), confirming the efficiency of the experimental systems used. Chronic exposure to these pollutants deteriorates sanitary status in fish, increasing the potential risk for the health of human consumers. In addition, the health of fish assessed by monitoring several physiological, biochemical and immunological parameters was shown to be disturbed. Indeed, leucopenia due to lymphopenia and a decrease in phagocytic activity were observed in fish whatever the experimental exposure conditions, affecting innate and adaptive immunity. Following the infectious challenge with the viral hemorrhagic septicemia virus, pendimethalin seemed to accelerate fish mortality and a high number of seropositive fish was recorded compared to the group of control fish. Finally, these effects were observed at exposure levels below the currently estimated predicted no-effect concentrations (PNEC), highlighting the importance of taking into account sanitary status and the components of the immune system in aquatic organisms when establishing environmental quality thresholds.
Bibliographical reference: www.cedre.fr/pmb/opac_css/index.php?lvl=notice_display&id=9281