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4A - Integrated ecological and human health RA (MO18/7) Human gastrointestinal mobilisation of food-borne PCBs: In Vitro Approaches. Soyibo, Adeola1, Beck, Angus1, 1 Imperial College of Science, Technology and Medicine, Wye, Ashford - Kent, UK ABSTRACT- PCBs are implicated as possible agents in causing cancer of the colon, breast and pancreas therefore we are seeking to establish, quantitatively, typical human exposure to such compounds. The commonest route of exposure to many PCBs is through food consumption but risk can be best associated with the bioavailable fraction that is mobilised and absorbed across the gastrointestinal membrane rather than the total concentration of contaminants in the food. Here, we report on the potential for gastrointestinal (GI) mobilisation of food-borne PCBs in humans. The development and validation of a GI simulator and operational protocols (based on the German DIN19734 protocol) are presented. Food, naturally contaminated with PCBs, was homogenised with simulated saliva fluid and shaken in the GI simulator with simulated gastric fluids (containing pepsin, mucine) for 2h at 370C. Afterwards, the simulated intestinal fluids (containing pepsin, mucine, trypsin, pancreatin, bile) were added and the mixture shaken for a further 6h prior to centrifugation and filtration using Buchner funnels to separate the undigested GI residues from GI fluids. PCBs were recovered from GI residues and fluids by Soxhlet and liquid-liquid extraction respectively, cleaned up using silica-SFE, and analysed by GC-MSD. Detailed studies with fish indicate variations in mobilisation and bioavalability of Key words: gastrointestinal, bioavalability , mobilisation |
PCBs (28, 52, 101, 118, 153, 138 and 180). For example, the bioavailable fractions (fractions mobilised) in salmon, mackerel, crab and prawn were 60, 75, 54 and 72% respectively of the