Wednesday 1 January 2014

Decontamination solutions for polychlorinated biphenyls (PCBs) in raw fish oils from environmentally contaminated sea fishes

Science of The Total Environment
Volumes 468–469, 15 January 2014, Pages 1007–1013

Fish oil has been identified as one of the most important contributors to the levels of polychlorinated biphenyls (PCBs) in food and feed products. In this study, PCB adsorption from fish oil onto activated carbon (AC), other sustainable adsorbents (mussel shell and wood waste ashes) and organic solvent such as ethanol were compared and optimized. Regarding to adsorbents, PCBs were extracted from fish oil by a 2.0% adsorbent material dose, during 6.0 h at 25 °C. Solvent extraction was carried out using 2 × 5.0 mL ethanol by manually stirring for 3.0 min, and then by Ultrasound-Assisted Solvent Extraction (UASE) for 5.0 min. The results showed that removal rates obtained by using adsorbent materials ranged from 0.0 to 10% for marker PCBs, from 0.0 to 37% for mono-ortho-PCBs, from 0.0 to 74% for PCB11 and from 0.0 to 95% for non-ortho-PCBs. Regarding to solvent extraction, ethanol was used by manually stirring and then by Ultrasound-Assisted Solvent Extraction (UASE). The samples were then centrifuged (2000 rpm/10 min) and the alcoholic phase was removed. With this method, removal efficiencies were much better (85–116%); nevertheless, high eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) removal rates (70–78 and 71–79%, respectively) were detected. We can conclude that adsorption with adsorbents depends on the geometry of PCB congeners, as well as both type of adsorption material and their origin, and that several sorption cycles are needed. Adsorption with ethanol could be the most effective methodology but nutritional quality was impaired, what makes necessary to look for other not so polar removal solvents.