Polychlorinated biphenyls in farmed and wild Onchorhynchus kisutch and Onchorhynchus mykiss from the Chilean Patagonia.

Purpose: This paper analyses the presence of polychlorinated biphenyls (PCBs) in escaped: farmed and wild salmons in southern Chile, analysing their concentrations and congener profiles in two species (Oncorhynchus kisutch and Oncorhynchus mykiss).
Methods: Muscle samples from both farmed and escaped fish of two species, O. mykiss (rainbow trout) and O. kisutch (coho salmon), were analysed for PCBs (42 congeners). To differentiate between the wild salmon and the salmon that have escaped from fish farms, the astaxanthin content in the muscular tissue was analysed with a high-performance liquid chromatography -diode array detector method. PCBs were measured by gas chromatography with an electron capture detector.
Results: The levels of astaxanthin can be used to differentiate between farmed, escaped and wild-borne salmons with statistically different concentrations. When comparing the total PCB concentrations for both trout and salmon samples, it can be determined that a separate analysis for farmed, escaped and wild-borne fish more accurately describes the real differences in the concentrations; these differences are hidden when separate analyses are not performed. The congener profiles are similar in both trout and coho salmon, where the tri-, tetra- and penta-CB congeners are the most abundant.
Conclusion: This study is the first report of PCBs in wild-borne, farmed and escaped salmons for the Southern Hemisphere, considering that Chile is actually one of the principal world producers of salmon.