| Summary: | International audience The polar and subpolar ecosystems receive persistent organic pollutants (POP) by atmospheric transfer. PCBs (polychlorinated biphenyls) and other ubiquitous organochlorines were detected from the late sixties. In subpolar areas, the snow acts as a dynamic reservoir. A multidisciplinary study funded by the French National Research Agency (ANR Risker program) in collaboration with the French Polar Institute (Immunotoxker program 409) began in 2009 to participate in the assessment of the global contamination, among others. In this objective, the Kerguelen Islands constitute a model of area not directly exposed to industrial, agricultural or urban pollution. This archipelago in the Southern Ocean possesses a complex hydrological network, with an ichthyofauna composed of salmonids introduced in the fifties. This first study relates to the contamination of trout (Salmo trutta) with organochlorine pollutants. These chemicals were widely used for over 50 years and are highly persistent and responsible for (eco)toxicological concerns. Also, the bioaccumulation assessment is concomitant to the measurement of hepatic enzymatic biomarkers involved in biotransformation process and protection against oxidative stress. The PCBs bioaccumulation shows a large heterogeneity, which results in average concentrations close to 250 ng per g dry weight, including optimal values in some individuals, reaching 5 micro g.g-1 dw. Moreover, we describe seasonal variations, with contamination level increased during summer, and inter-site differences in connection with the habitat. So, trout from the lake ecosystems are more impacted than river fish. Furthermore, lower levels of organochlorine pesticides were detected. The liver biomarkers respond to the contamination by a large variability. However statistical correlations indicate a relationship between biomarkers and bioaccumulation, particularly between the liver catalase and the concentration of prioritary PCBs, suggesting an immunotoxic effect. The continuation ...
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