Maternal transfer of organochlorine compounds to oocytes in wild and farmed gilthead sea bream (Sparus aurata).

To investigate the transfer of lipophilic organochlorine compounds to the gonads in gilthead sea bream females, liver and oocytes from wild and farmed females, just before spawning, were analysed by gas chromatography coupled to tandem mass spectrometry after clean-up of the fatty extracts by normal phase HPLC. This analytical methodology allowed us to achieve limits of detection of around 0.1 ng/g. Data obtained show that the chemicals studied are transferred from the liver to oocytes in ratios up to 0.51. In general this means that less than a half of pollutant load is transferred from liver to oocytes. A significant correlation (p<0.05) between log K(ow) and ratios (oocytes/liver) was found. Compounds with larger Log K(ow) present lower lipid-based concentration ratios (oocytes/liver). We have inferred that the reason the fugacity model is not accomplished is specifically dependent on the vitellogenesis process, which involves the transfer of lipids from the liver to oocytes in teleostei. No significant differences (t-Student) have been found between wild and farmed females transfer ratios (oocytes/liver).